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Nickel-Iron Battery
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This page is deliberately somewhat free-form to allow an open exchange of ideas regarding the development, within an Open Source Ecology economy, of a Ni-Fe battery, a somewhat esoteric subject. The further down the page you go, the more free-form the information.

Source Materials

The Global Village Construction Set
Nickel-Iron Battery

Nickel Compounds

Iron Compounds

Electrolytes

Other

Sources and pricing

FusionBeads [1] 3"x3" 24 gauge nickel sheet is $3.25.
Metric: 76.2x76.2mm and 0.5mm thick. The density of nickel is 8.902 g/cm3. 2903.22 mm3 which is 2.90 cm3. Thus, each sheet weights 25.84g. 2000g (2kg required as above) is 77.38 sheets. $251.50 is the cost of 2kg of nickel. Actually, it can be gotten cheaper in these quantities, but this is an outside number.

We need to look into purchasing in bulk as it is far cheaper than this sheet. Those guys must be making generous profit to say the least.

Wikipedia indicates that the price of metallic nickel these days is about 13 USD a kilogram, but it has been in the fifties during certain price spikes, I could not find a historical record, or even the current commodity price anywhere.

There are several ways to make the nickel electrode and active material which require different raw materials. See electrode sections for details. To both produce the nickel oxyhydroxide or hydroxide either inside the electrode matrix or as a powder of good particle size and porosity, which is then mixed into a paste and pasted into (with a matrix electrode) or onto (with a metal plate electrode, needs other additives to the paste) the electrode, there are several established economical ways that involve different raw materials, all of which will have different prices and availabilities:

-Use a metallic nickel which is then oxidized electrochemically in a suitable chemical bath - Use the oxyhydroxide or hydroxide powder, which can be purchased directly in purities adequate for battery use - Nickel oxide (NiO2 I think), which is then roasted in air to oxidize it to the oxyhydroxide - Nickel nitrate, sulfate, and potentially other salts can be melted, the electrode dipped in, and then the electrode dipped in hot sodium hydroxide solution to convert the nickel through a binary reaction to nickel hydroxide. This has to be repeated several times to load the electrode. - To produce nickel hydroxide powder from some other salts, the nickel salt is sprayed into a basin of sodium hydroxide.

As long as we have nickel compound of adequate purity it's just a matter of figuring out an economical production method, or using an existing one. Which material will be needed can be chosen on price, availability and the ease and economy of the associated manufacturing technique.

Nickel could be recovered from the waste stream too, but this might not end up saving any money.

Iron as an element or in the form of steel is cheap, but a look on alibaba.com indicates that it may cost substantially more in pure iron powder. We might want to make our own in the production phase, especially if a design which only uses a fraction of the iron as active material is chosen. The first problem is purification, in which the carbonyl process or other industrial processes might be useful in scaled down form, but this is where the contributions of a chemist would be particularly welcome as there is probably something which is more practical. Then it needs to be powdered either mechanically or through chemical or electrochemical processes, or some combination thereof.

Purification may not be badly needed. It would improve performance but how much so needs to be worked out so an informed decision can be made.

The Edison process for producing the iron powder was much like what references indicate is the current process used for producing the powder for pocket plate batteries [the battery handbook, 3rd edition]:

- dissolve "pure iron" (how pure, what impurities are problematic can be nailed down to a fair degree from the documents listed in the sticking points section). - The FeSO4 is then re-crystallized (are we talking fractional crystallization here to purify it?), dried, and roasted (815 to 915 deg. C) (in what atmosphere? Air probably) to Fe2O3.

- The material is washed free of any remaining [iron] sulfate, dried, and partially reduced in hydrogen.

-The resulting material (Fe3O4 and Fe) is partially oxidized, dried, ground, and blended. Small amounts of additives, are blended in to increase battery life, depassivate the iron electrode, reduce gas production, and improving conductivity. (See other reaction and additives sections for details on potential additives.)

There are other ways established ways:

Heating iron oxalate in a vacuum produces a mix of iron and iron oxide powder High purity iron powder like carbonyl powder

Price of Nickel and Iron

http://www.indexmundi.com/commodities/?commodity=nickel price is very roughly $23 per kg. Pretty good really. http://www.steelonthenet.com/commodity_prices.html price $0.60 per kg for scrap steel, presumably pure iron would be in that range.

From the electrochemistry figures above for a 1 kWh unit, that would be $48 or so on metals. So 20 Wh per $ ($0.05 per Wh). Even the cheapest lead acid batteries are 7 Wh per $. In reality they are more like 5. So the good news it that materials cost should not sink the ship anyway, although I'm sure all the other costs for the perforated pocket, assembly etc. will add up plenty fast.

Patents

0678722: Reversible Galvanic Battery: edison us patent fist one metioned in wikipedia also appears to be on nicad not nickel iron)
0692507: Reversible Galvanic Battery: (edison, second one mentioned appears to be on nicad batteries not nickel iron)
0827297: Alkaline Battery: (edison)
1402751: Storage Battery Electrode and the Production of Same: (edison)
3622398: SEALED TYPE STORAGE BATTERY : points out the formation of h202 might be a problem leading to excess h2 and also exposure to electrolyte mist etc.though modern batteries seem to have overcome this
3630778: METHODS AND MEANS FOR RECOMBINING HYDROGEN AND OXYGEN IN A SEALED BATTERY AND CONTROLLING RECOMBINATION AT CATALYST SURFACES: Osmium and iridium might be cheaper
3650835: PREPARATION OF BATTERY PLATES WITH IRON OXIDES HAVING A FUSED COATING :
3785867: BATTERY PLATES COMPRISING A MULTIPLICITY OF PERFORATED METALLIC FOIL ELEMENTS AND A BATTERY UTILIZING SAME
3819413: RECHARGEABLE METAL ELECTRODE FOR STORAGE BATTERIES AND METAL-AIR CELLS: nother iron electrode
3836397: IRON ELECTRODE FOR ALKALINE CELLS: another one on iron electrode activated with sulfur etc not sure what the other parts were
3849198: IRON ELECTRODE PASTE FOR ALKALINE BATTERY PLATES
3853624: HIGH ENERGY DENSITY IRON-NICKEL:
3895961: Electrodeposition of iron active mass
3898098: Process for producing iron electrode: (electrodeposition method, says that electrodes used today (1975) are almost identical to those used by edison, says easy to deposit ferrous hydroxide, might be wrong hydroxide?)
3941614: Method of preparing high capacity nickel electrode powder
4016091: Method of preparing high capacity nickel electrode powder: says nickel coated steel wool is good
4029132: Method of preparing high capacity nickel electrode powder: again steel wool
4064331: Method for the preparation of iron electrodes: (iron electrodes for batteries; the patent on pyrolized resin and carbon black being used as the support matrix nickel plated screws)
4098964: Storage battery with recombination catalyst : catalyst info
4207383: Negative, highly active iron electrode: (iron electrode maybe not useful)
4335192: Method of preparing a sintered iron electrode:ammonium halogenides suitable for activating iron electrode
4374907: Gaseous hydrogen and oxygen combining and condensing device: preventing water on the catalyst surface
4383011: Multicell recombining lead-acid battery: redistribution of the water produced to ensure continuing electrolyte balance, the problem could be avoided by having the cells atmospheres independently sealed but that might be more expensive or harder, especially if catalytic combination is needed since a seperate combiner would be needed for each cell in the battery.
4399005: Method of nickel electrode production: (with zinc hydroxide)
4519425: Control method for loading battery electrodes: diffusion bonded steel wool? also mentions vacuum impregnation and hand pasted and centrifuge
4540476: Procedure for making nickel electrodes: a good one, forming nickel electrode straight on the electrode electrolytically looks like this could be transferred from a main electrode to the acceptor electrode in an electrode production tank too so you could form nickel electrodes from nickel ingot (need to check solubility of hydroxide)if you could get metal for some reason checked alibaba though and looks like it is more expensive substantially actually ,
4623600: Low shear nickel electrode: high stresses exist in the electrode applies to NiMH but check the molar volume change for nife might matter also streses caused by gas pressure
4663256: Nonsintered nickel electrode: another plastic emulsion type
4844999: Nickel electrode for alkaline battery and battery using said nickel electrode: porous electrode prob nihm
4908282: Recombinant battery and plate separator therefor :
5151162: Rechargeable storage battery with electroactive organic polymer electrodes in polar solvent electrolyte: electrically conductive polymers, maybe some of them would make sense as a conductinve substrate that's easy to make and low cost
5200282: Nickel electrode and alkaline battery using the same: (electrode rather than plates if wanted high disshcarge currents maybe) (nickel plate mesh, remove substrate)
5290640: Sealed rechargeable battery :
5506067: Rechargeable electrochemical cell and cell case therefor with vent for use in internal recombination of hydrogen and oxygen: takes the opposite approach, letting 02 into the cell to recombine excess h2 rather tahn lettign h2 out , maybe an osmotic membrane of Cellulose acetate could allow escape of excess water or equilibrium could be acheived soon enough as the chemical consumption of oxygen in the cell slows down . What about adding peroxide to the electrolyte during production to cause that equilibrium to be reached faster?
5788943: Battery-grade nickel hydroxide and method for its preparation:
6193871: Process of forming a nickel electrode (forming nickel electrode)
6254841: Recombination system for the catalytic recombination of hydrogen and oxygen, forming in storage batteries, into water:
6261720: Positive electrode active material for alkaline storage batteries: (have no idea if this is useful, something about a nickel hydroxide electrode in alkaline battery though I think this is probably be applicable to nickel metal hydride only ther eare many on nickel hydroxide electrodes)
6265112: Method of making a nickel fiber electrode for a nickel based battery system: another
6333123: Hydrogen recombination catalyst:
6492062: Primary alkaline battery including nickel oxyhydroxide: (nickel,zinc)
6500576: Hydrogen recombination catalyst:
6991875: Alkaline battery including nickel oxyhydroxide cathode and zinc anode: (another nickel zinc)
7081319: Preparation of nickel oxyhydroxide: (preparation of nickel oxyhydrozide with ozone suitable fo use n battery (ozone is easy to produce with high voltage electrodes))
7407521: Process for producing nickel oxyhydroxide by electrolytic oxidation: (process to produce nickel hydroxide maybe not useful though)
7435395: Alkaline cell with flat housing and nickel oxyhydroxide cathode: (another nickel zinc)
7691531: Alkaline primary battery including a spherical nickel oxyhydroxide: primary battery with nickel oxyhydroxide there seems to be no attempt make to contact the active material with a matrix but it is a high current discharge battery probably capable of more than 1C. read again maybe there are spherical particles, also the crystal structure might be a reason , also it expands after being added to battery apparently so that might be causing compressive stress if there are conductive particles too, could be a useful way to get the needed force
[2]: Recombiner system : catalyst Sealed battery doc describes way to make catalyst but takes a lot of platinum

patent 3583624, porous fiber matt described in such a way that surface arae can be calculated is okay at 0.5 C also describes a process used to load the electrodes that sounds like a lot of work, precipitating the iron in the electrode matrix, also says "electroprecipitation" can be used without elaborating.

http://www.freepatentsonline.com/4064331.html mentiones activating iron oxide by soakin in h2s water (h2s highly toxic note similar to cyanide but strong odor at subtoxic levels so relatively safe )also provides brand names for iron oxide might give an idea of purity freedom from various compounds required , is using pyrolized polymer and carbon as electrode maybe coudl use well heated pyrolized biomass instead of carbon and some other polymer or material for carbon but this seems to be only for small electrodes of 1.7 grams but may be used in conjuntion with other methods

more

Swedesh pat.Nos 8.558/1897, 10.177/1899, 11.132/1899, 11.487/1899 and German Patent No.110.210 /1899.
US.Pat No.678.722/1901, 692.507/1902 and German patent No 157.290/1901
http://edison.rutgers.edu/patents/01488481.PDF
didn't look at http://www.patents.com/us-4330603.html

may be other patents, companies that make them and search freepatentsonline using the advanced search function for assignee name may turn up more and more recent

http://www.freepatentsonline.com/3911094.html producing nickel oxydydroxide also discusses self discharg mechanisms of anode interesting but not needed might reduce self discharge rate
http://www.freepatentsonline.com/EP0587973.html
http://www.freepatentsonline.com/EP0723305.html
[ii] Patent Number: 4,863,484 [45] Date of Patent: Sep. 5, 1989

http://edison.rutgers.edu/battpats.htm

All (purportedly) of Edison's battery related patents, and it looks as though a large fraction of them relate to nickel iron directly or indirectly, from production of raw materials to the geometry of the electrodes. I started going through them but my computer is too slow. Most of them appear to be highly relevant; because he did not have high grade commodity materials to work with, this appears to be nearly an instruction book on making batteries from relatively low grade materials, although it might not be as good as a modern commercial one that remains to be seen, especially with a modest redesign combining the modern information above (and there is more like it I'm sure).

patent number 5,788,943 Aug. 4, 1998

http://www.freepatentsonline.com/4335192.html The classical method, dating back to Edison, for producing active metallic iron powder involves dissolving the pure iron in sulfuric acid, subjecting the iron sulphate derived from the solution to a baking process at 900° C., and reducing it in hydrogen current at 450° C. after washing and oxidizing drying. The iron powder so formed can subsequently be sintered either in the dry state or as a moist paste in an H 2 current after application to a support, and thus formed into an electrode. Later electrochemical processes for making active iron masses have also become known, e.g., in accordance with Austrian Pat. No. 320,770, which teaches the electrolysis of an iron nitrate solution, with copper salt added to it.

http://www.freepatentsonline.com/4443526.html nickel oxide electrode "A very suitable material is nickel coated steel wool." for current collector of cathode "As can be seen from FIG. 2, the cobalt containing electrode paste of this invention provides pasted electrodes which retain theoretical output of about 0.26 ampere-hours/gram for between 25 to 38 cycles, curves (A) and (B). Without cobalt additive, output drops to below 0.20 ampere-hours/gram of NiCO 3 ." But this is for a nickel oxide electrode. Note also that the efficiency with which the active material is used is very high, wonder if we can get this with oxyhydroxide

http://www.freepatentsonline.com/4236927.html High curretn hihgly active more on a sintered iron electrode Numerous attempts have already been undertaken to maintain the polarization within acceptable limits, for example, in that one mixes active iron material with nickel flitter (very fine nickel flakes) as conductive substance and stuffs this mixture into steel pockets or small steel pipes. This electrode type is very stable and sturdy; however, it can be operated only with small current strengths.[the pocket electrode edison used? need to check edison patents he may not have added the flitter or used adifferent metallic material for conductivity]

"A simultaneous cathodic separation of iron and of a conductive material such as, for example, nickel, entails a further improvement; " what does this mean?

another sugested option might be mixing pure iron powder with sodium chloride solution,sintering adnduring sintering the sodium chloride prevents the particles from sticking together so much as to reduce the surface area more than needed, then removing the excess chloride by dissolving it, read in previous patents that this can help with leectrode activation as well as mentioned it corrodes small pores in the surface of teh iron , also in the process when sinterin gis done in an atmosphere of H2 activates the electrodes (removes oxide I think although not quite sure yet what electrode activation altogether necessarilly entails). Even better use feric chloride then rather than dissovling it reduce it with hydrogen gas to form iron apparently works well, Note that this may not have been tested for lon gterm urability but they are in the know and do no expect it to be a problem and why patent something unless pretty sure it is useful unless they are just putting up fences in case it might be useful, also the patent said that "The theoretical capacity with respect to weight of an iron electrode lies at 960 ampere hours per kg (Ah/kg). In practice, once reaches capacities of about 200 to 250 Ah/kg because" this indicates that the cost calculations for the raw material amount of iron is much higher than the naive electrochemical equations, it migh tals obe comparable for the cathode reaction which would be bad but from descriptions for other electrode producing methods this might be wrong or out of date (filed 1978) check with that starved electrolyte nickel iron battery paper to see if can extract data on the actual performance vs. theoretical that they acheived

note the tendency to use diffusion bonding to connect fibers involved with fiber elecgtroe plaques, in many cases no tmentioned but may be important. Can probably calculate bulk specific resistance with and without bonding, contact resistance between 2 metals just touching not bonded can be found in references.

http://www.freepatentsonline.com/4250236.html says lithium hydroxide not needed "tubular electrodes"? "bonded iron plastic elctrodes"? Maybe an electrically conductive polymer would eb convenient maybe with metal fibers embedden in it "The positive electrodes were intentionally made with larger capacities than the negative electrodes" it shoudl be the other way around, otherwise you risk reacting the entire iron electrode during discharge and the iron usually provides some of it's own current collector matrix, maybe they made a mistake or maybe they did it on purpose for testing or something.

http://www.freepatentsonline.com/4250236.html

still doesn't explain how the variation in electrode geometry changees with charg/discharge cycles, but it seems that it is assumed that it stays more or less the same for some reason i.e. an electrode that has a high surface area to weight ratio when new will continue to have one, and without the need for additives or anything like that. Maybe the hydroxide precipitates out right after being formed and stays more or less put on the surface, and likewise does nto travel far during charging though ther must be some diffusion and maybe this is part of what limits battery life. Alternatively on in combination with this, maybe the processes during reformation of the electrode during chargnine are remarkable symmetrical with the ones during recharging, leading to a very slow reduction in surface roughness/porosity, or it usually goes up over time so as long as you start high engouh to be good you're okay.

Still need to identify the temperature dependent capacity loss mechanisms http://www.freepatentsonline.com/4132547.html another electrode one for the iron electrode, there are so many am skipping most of them, they can be found by searching easily http://www.freepatentsonline.com/6335120.html polymer support matrix , helps explain the method used to make the electrode in the sealed nickel battery testing doc, applies to both electrodes, why would you add syncrystallized materials they mention? could semimelting of the polymer work to provide adhesion thereby replace some of the ingredients here reducing ingredient count?

Performance/capacity loss mechanisms identified thus far:

http://www.freepatentsonline.com/4236927.html I think mentioned that the interfaces between the iron particles in a sinterd electrode can oxidize with some electrode production methods, increasing the resistance of the bulk of the electrod's current collecting matrix to high level,

Oxidization of the iron to iron oxide causes electrode passivation, the addition of something to provide sulfide ions in electrode or the electrolyte causes reductino of the pxide on an ongoing basis, but eventually the sulfide oxidises to sulfate and doesn't go back,

http://www.freepatentsonline.com/4250236.html says passivation occurs more so at *low* temperatures, not higher , also points out depletion of sulfide is one mechanism by which it is due to oxidization of sulfide to sulfate

The marketing material for e.g. nickel-iron-batteries.com indicates that there is a reaction that occurs which produces capacity loss with time and is more problematic at higher temperatures. This has not been identified yet and should be.

Activation of iron electrodes:

http://www.freepatentsonline.com/4250236.html so sound like pretty much a mattery of getting and keeepinng oxides off and keeping them off

http://www.freepatentsonline.com/result.html?p=1&edit_alert=&srch=xprtsrch&query_txt=Iron+sintered+electrode+battery&uspat=on&date_range=all&stemming=on&sort=relevance&search=Search

Battery-grade nickel hydroxide and method for its preparation B Aladjov - US Patent 5,788,943, 1998

http://edison.rutgers.edu/battpats.htm

patent 01488480 describes some failure modes and fix looks like ause for the waste glycerine from biodeisel too

http://www.freepatentsonline.com/6335120.html (duplicate) Several types of electrode exist, in particular sintered electrodes and non-sintered nickel electrodes, also referred to as impasted or plasticized electrodes.
http://www.freepatentsonline.com/4064331.html the patent on pyrolized resin and carbon black being used as the support matrix

nickel plated screws http://www.freepatentsonline.com/4663256.html anothe plastic emulsio n type one http://www.freepatentsonline.com/4540476.html a good one, forming nickel electrode straight on the electrode electrolytically looks like this could be transferred from a main electrode to the acceptor electrode in an electrode production tank too so you could form nickel electrodes from nickel ingot (need to check solubility of hydroxide)if you could get metal for some reason checked alibaba though and looks like it is more expensive substantially actually ,

http://www.freepatentsonline.com/4462875.html electrodeposition electrochemical deposition also some further reading on it but is for catalyst might be not very suitable
http://www.freepatentsonline.com/4337124.html nothe electrodep

check our foreign patents too sometime

EP0889535 January, 1999 Nickel hydroxide active material for use in alkaline storage cell and manufacturing method of the same
JP0378965
http://www.freepatentsonline.com/4000005.html electrode for nimh but still may be applicable here also some about vacuum impregnation of the slurry (not paste?
might be able to use a microporous plastic filter pit fibermetal or paper against and then have the particles cake out on it a s afilter cake woud be limited though density

Options from patents (not all may be promising):

http://www.freepatentsonline.com/4873157.html no catalyst needed
http://www.freepatentsonline.com/4900642.html electrochemical recombination
http://www.freepatentsonline.com/4952465.html particularly interesting, additive maybe suitable for nickel iron
http://www.freepatentsonline.com/4908282.html mentions gas permeable film to let h2 out but not o2 and recombinant mat approach could be a bit cheaper than a mechanical vent
remember that the above options had probably been tried by industry for nife cells and yet references indicate it was not until recently, with the use of combiner caps, that sealed nife batts became available, so they might not work as well in nife fro various reasons
http://www.freepatentsonline.com/4629622.html more mat recombination
http://www.freepatentsonline.com/4987041.html aux elect rode but in a different way
http://www.freepatentsonline.com/6635387.html ammonium to reduce gas evolution in nickel iron batteries? the battery.

In French Patent No. 2,236,283 to Bonnaterre, http://www.freepatentsonline.com/5563004.html recombinant electrode in some other way General info on recombination and catalysts and how to make use of them practically:

http://www.freepatentsonline.com/result.html?p=1&edit_alert=&srch=xprtsrch&query_txt=battery+recombine+hydrogen+oxygen+seal&uspat=on&date_range=all&stemming=on&sort=relevance&search=Search patent search for recombination

Papers

SECONDARY BATTERIES – Electrodes: Iron

On the key importance of homogeneity in the electrochemical performance of industrial positive active materials in nickel batteries

SECONDARY BATTERIES – NICKEL SYSTEMS

The electrochemical generation of ferrate at pressed iron powder electrodes: effect of various operating parameters

SECONDARY BATTERIES – Nickel–Iron

DEVELOPMENTAL STUDIES ON POROUS IRON ELECTRODES FOR THE NICKEL-IRON CELL

The electrochemical generation of ferrate at pressed iron powder electrode: comparison with a foil electrode

The nickel/Iron battery

A nickel-iron battery with roll-compacted iron electrodes

Nickel-based rechargeable batteries Original Research Article Journal of Power Sources, Volume 100, Issues 1-2, 30 November 2001, Pages 125-148 A. K. Shukla, S. Venugopalan, B. Hariprakash

Passivation of iron in alkaline carbonate solutions Original Research Article Journal of Power Sources, Volume 35, Issue 2, July 1991, Pages 131-142 M. Jayalakshmi, V.S. Muralidharan

Iron/carbon-black composite nanoparticles as an iron electrode material in a paste type rechargeable alkaline battery

Electrochemical behaviour of Teflon-bonded iron oxide electrodes in alkaline solutions P. Periasamy, B. Ramesh Babu, S. Venkatakrishna Iyer

Electrochemical characteristics of iron carbide as an active material in alkaline batteries Kiyoshi Ujimine, Atsushi Tsutsumi

ASSESSMENT OF PERFORMANCE CHARACTERISTICS OF THE NICKEL-IRON CELL

Role of activation on the performance of the iron negative electrode in nickel/iron cells M. Jayalakshmi, B. Nathira Begum, V. R. Chidambaram, R. Sabapathi and V. S. Muralidharan* Central Electrochemical Research Institute, Karaikudi 623006 (India)

The role of FeS and �NH / CO additives on the pressed type Fe 4 2 3 electrode C.A. Caldas, M.C. Lopes, I.A. Carlos ) Group of Electrochemistry and Polymers, DQ-UFSCar, P.O. Box 676, CEP 13565-905,

TEMPERATURE LIMITATIONS OF PRIMARY AND SECONDARY ALKALINE BATTERY ELECTRODES SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025 (U.S.A.)

RESEARCH, DEVELOPMENT, AND DEMONSTRATION OF A NICKEL/ IRON BATTERY FOR ELECTRIC VEHICLE PROPULSION Eagle-Picher Industries Inc., C and Porter Streets, P.O. Box 47, Joplin, MO 64801 (U.S.A.)

Rechargeable alkaline iron electrodes K. Vijayamohanan, T. S. Balasubramanian and A. K. Shukla Solid-state and Structural Chemistry Unit, Indian Institute of Science, Bangalore - 560 012 @&a)

RESEARCH, DEVELOPMENT, AND DEMONSTRATION OF A NICKEL/ IRON BATTERY FOR ELECTRIC VEHICLE PROPULSION Westinghouse Advanced Energy Systems Division, P.O. Box 10864, Pittsburgh, PA 15236 (U.S.A.)

There are a few more which are probably available for free somewhere but which are still under copyright and therefore cannot be shared on the wiki, usually manuals on existing batteries etc.:

"the edison alkaline storage battery" doc from the edison battery company with some historical info about the batteries and their production

Operations manual(TN cell).pdf for changhong batteries(probably available on the changhong site)

"table 6 plus apendices" a piece of a manual for batteries that are in manufacture today, according to the person that sent me this doc they were made in Ukraine. (changhong=china)

Electrolyte Mixing Procedures V5611.doc This doc is for modern batteries still in production don't remember if it was ukraine or changhong ones

Changing Electrolyte pages 1 and 2.pdf this doc is for modern batteries, don't remember if it was the ukraine ones or the changhong ones

library

A lot of information has been gathered and this needs to stay available to other devs. For documents accessible on the net links should be provided, and the page should be spidered a few links deep to produce a backup copy the docs.

Some docs can be shared but aren't available online and I will upload the few I have and list them here.

Some docs cannot be legally put on the wiki but can be shared to at least 3 layers of passing the docs for free person to person, under fair use. A list of these ones I have now is below. Contact me at gregorfolouk@hotmail.com and I will send you a copy of any or all of them.

cyclic voltammetry studies of porous iron electrodes in alkaline solutions used for alkaline batteries

electrochemical behaviour of iron oxide electrodes in alkali solutions

performance characterisation of sintered iron electrodes in nickel/iron alkaline batteries

comparative studies of porous iron electrodes

electrochemical behaviour of teflon-bonded iron oxide electrodes in alkali solutions

rechargeable alkaline iron electrodes

Notes

The parts added by me,Gregor, are only my personal notes, essentially unedited and may be indecipherable, but it was that or much less research would be here because I only had so much time to put in. In some cases parts will appear to mean nothing to people who are not already knowledgeable on the subject, or there may even be notes that only make sense in context of what I was thinking at the time. I am a believer in a high level of transparency, and I could have chosen to leave this on my hard drive instead, but I am more interested in success than avoiding embarrassment. I am no longer working on this project much due to management issues on the OSE project so if you want it cleaned up you will have to do it yourself.

Did some googling around and making notes, here is what I found, this is ordered chronologically and I will try to organize the information into sections later, but this is only a sampling of the information available. Sorry about the perforated boxes, I have not been able to stop the wiki from doing that, and the lack of hard returns is another wiki quirk:

apparently their efficiency goes *up* with time over about 2 years 80% as mentioned in the forum, purportedly unknown exactly why, would be nice to know.
from the manufacturer's of the modern batteries seems like efficiency is reasonably high actually, was not able to determine if the charging efficiency is nearly equal to the round trip efficiency, so the graphs might paint an overly rosy picture, but I think it is pretty close

http://www.changhongbatteries.com/Ni-Fe_battery_for_Solar_&_wind_appliances_p53_m2.2.1.html

low quality taken from browser history:

higher quality

http://www.nickel-iron-battery.com/
http://fieldlines.com/board/index.php?topic=144379.0 says "combiner caps" catalytic caps are available
http://sustainabledesignupdate.com/2010/02/green-battery-design/ says they have/had a team developing them
I emailed them http://apptechdesign.org/contact-us/ as asking for any documentation they can send on their work
http://www.solarpowerforum.net/forumVB/off-grid/4509-nickel-iron-batteries-8.html on one page here includes list of manufacturers that currently make them

the product pages etc form blog post http://www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/chembox_edison-e.htm

May 19

I am making this a separate section because the wiki put a warning that the page may have been to long for some browsers to edit without breaking into categories.

Maybe look at the most specific or relevant patents and then search using the names of inventors etc.

The conductive scaffold for active material is referred to as a plaque of it is metallic (and maybe if not).

nickel iron cycle testing pdf has somethin gabout mucic acid to reduce the production of gas during charging that was from a pantent could probbaly find the patent

"Nickel hydroxide has been used for many years as an active electrode material for the positive electrode of alkaline batteries. The nickel hydroxide electrodes for these electrochemical cells traditionally fall into one of two major groups, sintered electrodes or pasted electrodes. Sintered electrodes are typically prepared by loading nickel hydroxide into a microporous substrate formed of a perforated steel sheet or mesh followed by sintering to form nickel oxyhydroxide, NiOOH.[why do the sintering if it is already loaded with nickel hydroxide??] The more recent pasted electrodes are prepared by producing an aqueous mixture of nickel hydroxide powder in a suitable carrier such as carboxymethyl cellulose. A porous metal substrate of fiber, foam or sponge is then impregnated with the solution to fill the pores of the substrate with nickel hydroxide. One advantage of the pasted nickel electrodes is the higher energy level approaching and even exceeding 600 mAh/cc compared to the typical energy density for sintered electrodes of about 400 mAh/cc. "

From the sealed nickel iron battery doc:

 Negative-limited Ni–Fe cells were assembled by stacking
 an iron electrode in between two sintered nickelpositive
 electrodes. The cells were housed in plexiglass
 containers in starved-electrolyte configuration, and were
 sealed with a plug containing 0.5 g of 2 at.% Pt/CeO2
 hydrogen–oxygen recombinant catalyst mixed with an
 equal amount of fumed silica. 6 V/1 Ah sealed, starvedelectrolyte
 Ni–Fe batteries were assembled in a plexiglass
 container comprising five compartments to

What? no Oxyhydroxide? When/how is it formed ?

maybe possible to form nickel hydroxide from metallic electrolytically, metallic nickel may be more expensive anyway though

faradaic efficiency of nickel iron cells, the sealed battery paper says is only 60% but again goes up over time to 80%

new docs

http://www.freepatentsonline.com/5989746.html listsa a few types of nickel electrode

searched "nickel iron batteries" on sciencedirect.com and went through the first 3 pages

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TH1-4679T4B-1B&_user=10&_coverDate=08%2F31%2F1995&_alid=1757348188&_rdoc=2&_fmt=high&_orig=search&_origin=search&_zone=rslt_list_item&_cdi=5269&_sort=r&_st=13&_docanchor=&view=c&_ct=5535&_acct=C000050221&_version=1

&_urlVersion=0&_userid=10&md5=f94cc3c3f3988c1195112305e5e27202&searchtype=a

it employs electrodes with the pocket plate construction wherein the active material is encapsulated between double perforated folded steel strips. http://www.hblnicad.co.uk/Our%20Products.htm

note, these links are all broken, I have gone back and retrieved the titles of the papers and others, they are listed lower down http://www.freepatentsonline.com/5989746.html a pocket-type electrode, obtained by compressing electrochemically active material, in this case hydroxide Ni(OH) 2 , mixed with a conductor, into a metal pocket having perforated walls so that the electrolyte can impregnate the active material, but the active material cannot escape from the pocket; and

Maybe vacuum for gettin gpaste into the porous electrode, expose electrode to vacuum, cover in paste then expose to atmospheric, paste gets sucked into electrode , could also put electrode in a pan then vover with paste and maybe do one vacuum cycle

make a complete contained widget machine or glove box for electrode production to contain the (moderately) toxic materials if have to use paste

Cost of nickel oxide and hydroxide to determin if they might be cheaper than metal nickel in terms of the quantity of nickel:

Prices on the pages are FOB: free on board; assumption of responsibility by shipper for all costs until goods are placed on carrier , whatever carrier is, presumabbly the shipping company.

Ranges from 7 to 30$ on alibaba.com some grades migh tnot be suitable for batteris due to impurities, this can probably be determined from the information in the scientific articles and some manufacturer's conveniently say it is suitable for batteries. Detailed analysis may be available from suppliers. Samples may be obtainable form suppliers for prototyping with the specific material of concern. NiO2 (oxide) and Ni2O3 (peroxide) or NiO see wikipedia for CAS numbers but the pages sometimes fail to distinguish saying oxide always? http://en.wikipedia.org/wiki/Dictionary_of_chemical_formulas/Merge/N note that chemical suppliers are sometimes very sloppy about talking about chemicals and chemical names and may make mistakes, a lot of chemists are, with oxide meaning any of the oxides so need to double check the exact chemical used in the patents if the route of producing nickel oxyhydroxide from nickel oxide by oxidization in o2 gas, ozone in solution or humid ozone gas or otherwise, is chosen.

Details on which impurities are problematic needs to be tracked down so the cheapest stuff that will do can be used. Testing works to some degree but not if the impurity causes reduced life which would go undetected. Nickel hydroxide I did not check yet because I still need to look at other patents and see if electrode can be made straight from it.

alibaba, jus tsearch nickel oxide or "nickel oxide" battery

conclusion: In terms of nickel content, depends on who it is purchased from etc. But it is usually substantially cheaper than nickel metal.

The if vacuum is use for pasted equivalent electrode, battery could be designed such that the pasting process occurs inside the battery maybe no point though, but trying to keep the reactions and toxic materials in the battery during manufacture rateher than needing to pour and transfer them would be nice , and using nickel metal as a starter material coudl be a perk in that regard actually nickel oxide not soluble in water is it? No do not accept "insoluble" as an answer, want to know exactly how soluble

Is apparent that the reaction products stay put where the reaction material was before, unlike in a lead acid battery where they form a sludge of material at the bottom of the battery, that assumption tripped me up for a bit there so be it known.

http://academic.research.microsoft.com/Paper/11920038 solubility of NiO

maybe post on amateur chemist forums when the time comes ask for help clearin up uncertainties, maybe experimenting like finding solubility of nickel oxyhydroxide or p

 iron air battery sounds interesing http://www.freepatentsonline.com/4474862.html wonder what the efficiency for rechargnin is probably very low, could make a good electrid lifetrack

No doubt this applies to searches in other venues as well like on sciencedirect etc.

While at first it appears there is relatively little info on these batteries there is a vast amount just under the surface that can be mined out and is fairly informative. Clearly after the information is mined out of the public spaces there will still be plenty left squirreled away by companies for one reason or another that is just not available to us. Some of this will need to be re figured out on paper by someone with some chemistry knowledge/ rediscovered though prototyping/testing/research.

aluminum air if coudl use aluminum elecrdodes from clay wonder how to make the gas permeable electrode though maybe coudl metallize a gas permable polymer layer with vacuum vapor deposition or similar or could maye the polymer slighlyt conductive and embed metallic fibers or similar

check out other ways to make active iron electrodes are probably lots of them, includes a low solubility sulfide mixed in the iron or added in excess to the electrolyte, adding sulfide to the iron electrode, other ways of getting sulfite where it needs to be, apparently present as an impurity in adequate amount in some iron anyway so thats handy.

nickel zinc might be worth lookin g into since they have higher cahrge/discharge efficiency are more efficient

searchable archive of the pdfs which I ocred, I tried to upload this to the wiki but it is more than 7 megs and not a permitted file type (.zip) not can batch uploading of PDFs be done, so maybe someone else can put this information on the wiki where it will not disappear in the future as it will on zippyshare, but will rather remain conveniently searchable for future developers: http://www30.zippyshare.com/v/76183680/file.html

why is it that edison keeps mentioning that sulfur is undesirable in the vulcanized rubber in the insulators but in modern batteries is is used to acitvate the electrode?

yet another optio nfo the anode is to take copper crystals and iron particles and compress them into a blockL 2683182 says low purity iron can be used for this

How hard would it be to make the nickel cloth again? if diffusion bonding is needed then that reduces the benefit of using steel wool and cloth can't release inhalable fibers when you dont want it to , maybe sintering not so bad either would be durable too , oh it nickel plating of the wool happens after diffusion bonding it says maybe beat or vacuum clean or blast with high pressure air the steel wool to reduce the amount of small fibers involved to reduce amount of stuff that migh tbe released subsequently maybe no point nickel metal anyway http://www.nmfrc.org/epadocs/1994f.htm on chemicall yplating steel wool

maybe nickel foil but without compression no probably not need the metal scaffold to be condictive throughout maybe a method could be developed to use salt or sugar and get the nickel foil bit sto bond with electrochemical plate-out

maybe plate-out on the active material or a polymer matrix?

check the polymer paste methods again maybe flouropolymer not needed coudl use a different material combo they mention also they explain why they use fluoropolymer, highly hydrophobic, maybe a substitute can be found.

also check the conductive pyrolyzed plastic again check conductivit of activated carbon etc to see conductivity of pyrolized biomass

http://acs.omnibooksonline.com/data/papers/1997_ii454.pdf looks very high 30 ohm/cm vs 6.9 microohm per cm for nickel, if the plaque is 10% dense specific resistivity of the resulting matrix material pretty high 300 ohm/cm maybe it is a lot lower with pyrolized polymers
http://webcache.googleusercontent.com/search?q=cache:VngbRXiriPcJ:acs.omnibooksonline.com/data/papers/2004_E060.pdf+http://acs.omnibooksonline.com/data/papers/2004_E060.pdf&hl=en&gl=ca says 1.99177x10-3 δ /cm which is plenty low esp if combine switha central nickel rod or nickel wire

that US3853624.pdf file gives an idea of the sort of fiber density and size that is suitable for electrodes

Maybe thixotropic material to prevent escape, have a look at gells again do the diffuse and sort of spread throughout a liwuid they are immersed in or stay solid maybe the nickel plating process would electrically attach the wool together appropriately

wool needs to be cleaned adequately first

with the iron electrode make it from scratch What to do about the need to obtain nickel from environment in abundance?

if do buy stuff needs to be commodity as possible so no buyin nickel wool or electroplate stuff then

That leaves the polymer maybe dense polymer fibers woudl work

bickel plated bolts for final termination, and probably a bit more fragile (though actually carbon fiber is pretty tough) so might want to make the branching of the fiber stuff heirarchical if can maybe test it for wtrenght first also extra dense can be done easily also support it in the casing of the battery with foam supports to distribute loads due to shock etc and make it a block instead of a plate maybe check the tensile strength of pyrolized plastics of varying sorts esp common and cheap ones remember carbon fiber is made by pyrolizing aramid right and we can make polyaramid 11 or whatever see wikipedia under biopolymers

need to find the patents that mentioned downsides of including carbon or graphite in the electrodes on either side

block can have veritcal and horizontal holes etc. easily to allow gas to excape s

for heirarchy could use fiber and powder together need to have contingency pland in case a certain commodity no longer available hardly, also need co calculate costs as go along they have to be less than commercial batteries, if as mentioned above only a quarter of the active electrode on iron side actually gets used (also tells how much material need to sinter to make the electrode), also on the nickel side need to know what fraction of active material gets used

"Eagle Pitcher Ni " is a commercial plaque sutiable fo rht enickel side

damn, went back to look at some of the scientific articles and the urls are all broken and cant be fixed. no correlation between url and articles at all .search browser history to find the title and put them with the urls so can find the articles again

scrap nickel prices? with electrolytic loading maybe particularly easy to use scrap metal though of course it can be used anyway in one way or another.

find what fraction of nickel can expect to be actually used for a battery like with iroon eectrode compare for different electrode types esp edison and nickel plated steel wool, in the scientific docs that describe construction of cell this would be revealed, maybe in some patents too, remember seeing the information on weight and amp hour capacity of a pocket electrode by edison in his patents, need to look it up again, the efficiency will probably be a lot higher for a pasted electrode.

bulk conductivity of steel wool at large medium and small scales

Okay my browser malfunctioned when I was searching for the names of the articles from my history and wiped out the history. So I search again for the best ones and started copying the titles downWe basically want all of them that mention nickel iron specifically and most of the others that relate to eletrodes made from nickel oxyhydroxide, and metallic iron and/or iron oxides. The electrode ones may not mention "nickel iron" per se because e.g. a good iron electrode in nickel iron battery can also be used in many other battery chemistries.

searched "nickel-iron" battery went through to end of second page

"nickel-iron" storage cell searched first page only one up at the top
"nickel/iron" battery searche dto the end of second page
Nickel iron battery need to record searched to the end of the 3rd page page
Nickel iron electrode record went through thr first 2 pages migh tbe more
also can look at the related papers section

Assessment of performance characteristics of the nickelnext term---previous termiron cellnext term

Self-discharge of Fe–Ni alkaline batteriesnext term

The role of FeS and (NH4)2CO3 additives on the pressed type Fe electrodenext term

The electrochemical properties of Fe2O3-loaded carbon electrodesnext term for previous termironnext term–air previous termbatterynext term anodes

Effect of metal-sulfide additives on electrochemical properties of nano-sized Fe2O3-loaded carbon for Fe/air batterynext term anodes

Passivation of ironnext term in alkaline carbonate solutions

Electrochemical characteristics of ironnext term carbide as an active material in alkaline previous termbatteriesnext term

Temperature limitations of primary and secondary alkaline battery electrodesnext term

97/03847 Performance characterization of sintered ironnext term electrodes in previous termnickel/ironnext term alkaline previous termbatteriesnext term

SECONDARY BATTERIES - NICKEL SYSTEMS Electrodes: Nickel

Assessment of performance characteristics of the nickelnext term---previous termironnext term cell

Nickelnext term-based rechargeable previous termbatteriesnext term

Developmental studies on porous iron electrodesnext term for the previous termnickel---ironnext term cell Performance characterization of sintered ironnext term electrodes in previous term nickel/ironnext term alkaline previous termbatteriesnext term

On the key importance of homogeneity in the electrochemical performance of industrial positive active materials in nickel batteriesnext term Electrochemical behaviour of Teflon-bonded ironnext term oxide previous termelectrodesnext term in alkaline solutions Rechargeable alkaline iron electrodesnext term high curent though Performance characterization of sintered ironnext term electrodes in previous termnickel/ironnext term alkaline previous termbatteriesnext term

The role of lithium in preventing the detrimental effect of ironnext term on alkaline previous termbattery nickelnext term hydroxide electrode: A mechanistic aspect looks like not just about nihm may be some applicable to nife too Role of activation on the performance of the ironnext term negative previous termelectrodenext term in previous termnickel/ironnext term cells Rechargeable alkaline iron electrodes

Microstructure changes to ironnext term nanoparticles during discharge/charge cycles The discharge capacity of the first cycle was extremely high, 510 mAh/g-Fe, at a current density of 200 mA/g-Fe, check what that is well, it;s 510 Ah per Kg as compared with the ~250 figures in the patents for sintered electrodes with reduced salts on their surfaces (a high rate one) and 960

Really interesting looking :\

Assessment of performance characteristics of the nickelnext term---previous termironnext term cell

SECONDARY BATTERIES - NICKEL SYSTEMS Nickel–Iron
SECONDARY BATTERIES - NICKEL SYSTEMS
SECONDARY BATTERIES - NICKEL SYSTEMS Electrodes: Iron

The nickel/ironnext term battery

A nickel-iron batterynext term with roll-compacted previous termironnext term electrodes

Less interesting:

The role of lithium in preventing the detrimental effect of ironnext term on alkaline previous termbattery nickelnext term hydroxide electrode: A mechanistic aspect

Iron/next termcarbon-black composite nanoparticles as an previous termironnext term electrode material in a paste type rechargeable alkaline previous termbatterynext term

Research, development and demonstration of a nickel—iron batterynext term for electric vehicle propulsion there are several papers with this term LO

Microfibrous nickelnext term substrates and electrodes for previous termbatterynext term system applications can't use them anyway most likely though maybe The fabricated previous termnickelnext term electrodes that included a supporting previous termnickelnext term mesh in the substrate tested in a 26% KOH half-cell delivered a specific capacity of more than 250 mAh/g of the electrode weight (i.e. fibrous substrate, previous termnickelnext term mesh, and active material) at a 1.0 C discharge rate. An Auburn electrode without a previous termnickelnext term mesh tested in the same half-cell attained a higher specific capacity of 268 mAh/g at a 1.37 C discharge rate. The substrates used in these electrodes had porosities of 95–97%, and greatly improved the specific capacity of the previous termnickelnext term electrode. With the use of the previous termmicrofibrousnext term electrode, improved specific energies of previous termnickelnext term-based cell and previous termbatterynext term designs are possible. When assembled in a previous termnickelnext term–hydrogen (Ni–H2) boilerplate cell, the specific capacity of nearly 230 mAh/g was observed for the previous termnickelnext term electrode at a 0.5 C rate during the 127th cycle test.

Assessment of performance characteristics of the nickelnext term---previous termironnext term cell
The electrochemical generation of ferrate at pressed ironnext term powder previous termelectrode:next term comparison with a foil previous termelectrodenext term
The role of FeS and (NH4)2CO3 additives on the pressed type Fe electrodenext term
Alkaline poly(ethylene oxide) solid polymer electrolytes. Application to nickelnext term secondary previous termbatteriesnext term

least interesting

Importance of alkaline accumulators in the application of renewable resources , can tell something about the needed performance reqs

Alkaline Battery Separators

The role of halide ions on the electrochemical behaviour of ironnext term in alkali solutions
Nickelnext term-based rechargeable previous termbatteriesnext term
maybe or clearly probably only applicable to nihm but didn't want to loose
Effect of zinc and ironnext term ions on the electrochemistry of previous termnickelnext term oxide previous termelectrode:next term slow cyclic voltammetry
An electrochemically impregnated sintered-nickel electrodenext term An electrochemically impregnated sintered-previous termnickelnext term porous previous termelectrodenext term with a capacity of 225 ± 10 mAh per g of active material has been developed nihm, can calculate from wikipedia how much that is relative totheoretical also in one of the above it was mentioned the overall weight of the electrode for a fibrous electrode vs. current per gram, could make asumptions actually said it was 97 oercent porous so that tells how much but migth be weightin the water too still puts a lower boundary
Electrocatalysis of anodic oxygen evolution at the nickelnext term hydroxide previous termelectrodenext term by ferric hydroxo species in alkaline electrolytes
The significance of electrochemical impedance spectra recorded during active oxygen evolution for oxide covered Ni, Co and Fe electrodesnext term in alkaline solution
The influences of some additives on electrochemical behaviour of nickel electrodesnext term
The role of lithium in preventing the detrimental effect of ironnext term on alkaline battery previous termnickelnext term hydroxide previous termelectrode:next term A mechanistic aspect
The effect of lithium in preventing ironnext term poisoning in the previous termnickelnext term hydroxide previous termelectrodenext term

may 21

http://www.freepatentsonline.com/5989746.html A nickel electrode of the pasted type is made by depositing a paste either on a two-dimensional conductive support such as expanded metal, a grid, a fabric, a solid strip, or a perforated strip, or else in a three-dimensional conductive support that is porous such as a felt, a metal foam, or a carbon foam. so carbon okay prob at nickel electrode though saw another one that mentioned it had significant downsides

a polymer cloth pocket could be used to keep the paste in, maybe this was partly what the pocket used in the sealed battery doc was for doubt it because had elastomer binde r
Document EP-0 658 948 describes an Ni--MH alkaline storage cell provided with a positive electrode of the pasted nickel electrode type constituted by nickel hydroxide, as its active material, and by graphite, as its conductor. The nickel positive electrode provides the storage cell with increased stability at high temperatures of use. Furthermore, it can be seen that the nickel positive electrode cannot be associated with a cadmium negative electrode, because, in that case, the graphite oxidizes into carbonate ions which pass into the electrolyte.
To increase the rapid discharge performance of a non-sintered nickel electrode, document JP-57 138 776 proposes a conductor constituted by a mixture of particles, preferably of graphite powder, and of fibers made of carbon or of stainless steel, for example. stainless steel okay?

purpose of cobalt additives mmight be to increase conductivivty

During the first charge of an alkaline storage cell provided with a nickel electrode containing a cobalt compound as its conductor, said compound is oxidized into cobalt oxyhydroxide CoOOH in which the cobalt is brought to oxidation number +3. The cobalt oxyhydroxide is stable in the normal operating range of the nickel positive elec
ask chemist if there is a conductive polymer that would be okay for the nickel (resistant to redox environment) and if it is expensive or coudl be synthesised by makers
there was on that mentioned that nichrome wire or mesh could be used migh tbe more available thatn nickel

Battery-grade nickel hydroxide and method for its preparation B Aladjov - US Patent 5,788,943, 1998

http://edison.rutgers.edu/battpats.htm patent 01488480 describes some failure modes and fix looks like ause for the waste glycerine from biodeisel too

http://www.freepatentsonline.com/6335120.html (duplicate) Several types of electrode exist, in particular sintered electrodes and non-sintered nickel electrodes, also referred to as impasted or plasticized electrodes.

maybe rods would be useful if nickel mulit strand wire is avilable or something

maybe putting the electrodes horizontally could be better to prevent loss of paste for one of the electrodes if wanted to eliminate binders and density an fibrosity of fiber mat was relatively low (like steel wool?), could then have either other electrode horx too with tray spearating it from the other one and conduction occuring aroud edges of tray also coudl have cloth barrier or something tightly woven to reduce escape of particles during mecahnica lagitation, or have electrolyte ffairly viscous with an additive, probably not much of a problem thoug heven if particle sget fro, one electrode to the other they would just stay there in the discharged state, main thing is to keep active material close to the current collector, also could be adjacent then stack for battery, check what effective the resistance of the electrolyte is, might be too high for this to be practical (ionic current of the relevant ions vs/ voltage). If a bed of fibrous nonwoven cloth material like tyvek or what is used often in depth filters for water filters, which is a effective particle barrier at the particle sizes concerned, but also a high porosity for ionic current, could form the bottom of the tray

in terms of shape changes of active material particles or mass that one with the nanoparticles had evidence of it changing but aparently happens quite little as was not a problem for even them causeing relatively little variation in particle size and total surface area thoug hit was growth in particle size/reduction in active area. wait, that migh thave been a nickel hydride cell double check, but in any case this is the assumption; very little change in particle or surface geometry occurs, though some does and this is taken advantage sometimes to electrolytically attach the particles together and to the current collector surface for better conductivity, also particles that are not attached such that electron current flow can practically occur are not utilized as active mass (they are wasted) so it's important to have them connected in this way. In edison cells a significant fraction is wasted, need to check again how much, can comput form wieght of the tubes etc.

should eventual;y preserve the research page by spidering to prevent link death being a problem, then upload the finished webpage with files maybe 3 deep for links so get pdf files for posterity since development will continue and also for repair manuals writing etc.

more docs:

google scholar'd "nickel-iron" battery electrode and went through the first 100 hits:
Journal of Materials Science Letters Volume 12, Number 9, 620-622, DOI: 10.1007/BF00465571 Electrochemical impregnation of the nickel hydroxide electrode under ultrasonic irradiation A. Chiba, T. Tani and Y. Ouchi
Electrocatalysis of anodic oxygen evolution at the nickel hydroxide electrode by ferric hydroxo species in alkaline electrolytes hi
Comparative Study of Fe2O3-Nanoloaded Carbon and Fe2O3-Nano/Carbon Mixed Composites for Iron-Air Battery Anodes
Electrochem. Solid-State Lett., Volume 8, Issue 9, pp. A476-A480 (2005) LO
6V, 60Ah nickel-iron battery.
Bulletin of Electrochemistry. Vol. 6, no. 2, pp. 263-265. 1990
High reversibility of the charge discharge reaction leads to the longest service life. The iron electrode has low hydrogen overvoltage. Its ionisation potential and hydrogen evolution potential are very close in alkaline medium. As a result, the self discharge of this system is 1-2% of the nominal capacity at 300K (1). The advanced Ni/Fe batteries with an energy density of 55-82 Wh/kg (2,3) serve as power sources for electric vehicles. The electrode fabrication techniques and the performance characteristics of the 6V, 60 Ah Ni/Fe battery are presented in this paper. * Very HI

Open-circuit potential—time transients of alkaline porous iron electrodes at various states-of-charge
Purchase
$ 31.50
Solid-State and Structural Chemistry Unit, and Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560 012, India iron air mostly LO

Effect of synthesis conditions on characteristics of the precursor material used in NiO·OH/Ni(OH)2 electrodes of alkaline batteries LO

Mechanisms of self-discharge of the negative of alkaline accumulators available as html without images through google's view as html, google title and there it is

   "The self-discharge of the negative in nickel-iron batteries is caused mainly by the
   anaerobic attack of the active material by water. As in other instances of corrosion,
   this process can be retarded by cathodic protection. A cadmium negative is practically
   immune against water, but in an incompletely sealed"
   It is known that the negative in alkaline nickel accumulators loses charge on
   standing idle, the loss being of the order of 20 % per month in Ni-Fe cells 1
   and 2-3 % per month in recent makes of Ni-Cd cells.2 In contrast to the lead-
   acid battery, no attention has yet been given to the corrosive mechanism causing
   self-discharge in the alkaline storage cell. 
   In  1955 thogugh porous nickel plate (6-3 cm x 1.7 cm x 0.3 cni) made from low-density carbonyl powder
   by sintering in H2 at 950” C without compression. The pore volume of the plate was
   85 % and the surface area was l-l*mz/g, as measured by the B.E.T. method. In one
   spiral and the negative. With a
   70-cm nickel strip, the rate of self-discharge was about 1000 times as fast as in the absence
   of a water-line. This effect was also found in commercial Ni-Fe cells, the water-line
   being present round the rod supporting the negative. On separating the latter from the
   rod, and inserting a meter, an air junction current of 0.3-0-4
   mA (in a 10 A h cell) was measurable. This current is large enough to account for t[sic] so nickel electrode needs to be submersed

also indicates that maybe id we pressurized the battery self discharge could be reduced but pressure might eb too high Also explains the main problem by far with self discharge in nife is that the iron reacts with the water

High energy density micro-fiber based nickel electrode for aerospace batteries LO

An iron—air vehicle battery

http://books.google.ca/books?hl=en&lr=&id=_PGzaO48Rz0C&oi=fnd&pg=PR4&dq=%22nickel-iron%22+battery+electrode&ots=WUrahYuzAm&sig=QjxT0uYcDvtejauBT0ClpFO9XZs#v=onepage&q=%22nickel-iron%22%20battery%20electrode&f=false

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Electrochem. Solid-State Lett. / Volume 4 / Issue 3 / BATTERIES AND ENERGY CONVERSION

Ceria-Supported Platinum as Hydrogen-Oxygen Recombinant Catalyst for Sealed Lead-Acid Batteries

Electrochem. Solid-State Lett., Volume 4, Issue 3, pp. A23-A26 (2001)

The influences of some additives on electrochemical behaviour of nickel electrodes might be interesting not clear

The effect of iron hydroxide on nickelous hydroxide electrodes with emphasis on the oxygen evolution reactionstar, open might be interesting since some particles will get in the nickel leectrode and eventually mix

Battery Basics [3]

Similiar Pages

The patent drawing for Edison's Alkaline Battery (827279)

Products and Projects

Commercial Ni-Fe Suppliers

Iron Battery Wholesale Suppliers in the World

BeUtiltyFree

http://www.beutilityfree.com/Electric/Ni-Fe

Changhong

http://www.changhongbattery.com/Ni-Fe_battery_for_Solar_&_wind_appliances_pm53_m3.3_g47.html

Ironcore Power

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http://www.zappworks.com/

Eagle-Picher (obe)

http://www.evdl.org/docs/ep_nife.pdf

For comparison purposes,

NICKEL OXYHYDROXIDE BATTERIES

Manganese Dioxide 20-30%
Nickel Oxyhydroxide 20-30%
Zinc 10-20%
Water 5-15%
Potassium Hydroxide (35%) 5-10%
Graphite (natural or synthetic) 2.5-4.5%

NICKEL METAL HYDRIDE BATTERIES

Nickel 55-70%
Cobalt 5-10%
Potassium Hydroxide (35%) 1-5%
Aluminum 1-5%
Sodium Hydroxide 1-5%
Manganese 1-5%

NICKEL CADMIUM BATTERIES

Nickel and Nickel Hydroxide 15%
Cadmium and Cadmium Oxide 28%
Potassium Hydroxide (35%) 2.5%
Cobalt (7440-48-4) and Cobalt Hydroxide <1%

Projects

Ed's Workshop

The Yahoo Group contains current efforts including a photo deck of his current battery. He also includes lots of other DIY projects that fit the theme here: DC motor control, Induction Furnace, Metal Casting, Electro-forming ...

Yahoo Group: http://tech.groups.yahoo.com/group/edsworkshp/
YouTube Channel: http://www.youtube.com/user/edsworkshop#p/u/14/CBGcdtAzzUE

Suggested Source:

Nickel Carbonate (Baily Pottery) approx $28/lb or less (depending on size of order)

http://www.baileypottery.com/clay/clays-chemicals.htm

noonco

Edison Battery Construction Nickel Iron‏ - YouTube: http://www.youtube.com/watch?v=K84PywMwjZg
Edison Battery Page: http://www.noonco.com/edison/

Chemistry

Handbook of Batteries, 3rd edition (more details available in that reference):

Fe + 2NiOOH + 2H₂O <---> 2Ni(OH)₂ + Fe(OH)₂ (first plateau)

3Fe(OH)₂ + 2NiOOH <---> 2Ni(OH)₂ + Fe₃O₄ + 2H₂O (second plateau)

The overall reaction:

3Fe + 8NiOOH + 4H₂O <---> 8Ni(OH)₂ + Fe₃O₄

Discharging is left to right, charging is right to left.

"Plateau" refers to a region on the voltage vs state of charge of the iron electrode.

In practical batteries the second plateau is not normally used for various reasons even though avoiding it entails adding a lot of extra iron.

Theoretical specific energy using only the first plateau:

55.8+32+2 = atomic mass of discharged iron = 89.8

58.69+32+2 = atomic mass of discharged nickel electrode = 92.69

1 electrons per molecule nickel hydroxide, so roughly 10^5 coloumbs per mole of electrons, 27.7 Ah at 1.2 volts (33.3 Wh) or so per mole, 182.49 g, so 182.48 Wh / kg theoretical with 100 percent utilization, including the water as a reactant but not the electrolyte (of which only a vanishingly small amount is theoretically needed).

Additives

- cobalt hydroxide is used to improve conductivity of the nickel electrode either by adding it to the nickel oxyhydroxide at manufacture or into the powder after, by e.g. coating the particle electrolytically to give them a higher effective conductivity without interfering with their reactivity too much (it does reduce it a little though so again there will be an optimum amount). It can also help to increase the fraction of active material that is utilized. 1 to 5% of the active material mass may be used for this. We probably want to avoid bothering with this.

- metallic cobalt to the metallic mesh, function needs to be checked, probably to improve contact resistance and reduce oxidization of the mesh and maybe reduce corrosion rate by electrolyte.

-sulfur, tellurium or selenium compounds are used to activate the electrode, see other reactions section

-carbon black is sometimes added to pocket plate electrodes to improve bulk conductivity of the active material mass

-graphite particles can also be similarly added for pocket plate electrodes

Construction

Anode Compound

iron plate - low carbon, mild steel (demo)
iron graphite compounded (Edison)
iron oxide

Anode Construction

plain plate (demo)
pocket plate with mesh inserts (Edison)

Cathode Compounds

nickel(III) oxide-hydroxide
nickel hydrate and pure nickel flake (Edison)

Cathode Construction

plain plate (demo)
pocket plate with mesh inserts (Edison)
generally nickel-plated rather than pure nickel

Nickel sponge
Sintered nickel powder
Nickel mesh/cloth

Electrolyte

potassium hydroxide
sodium hydroxide (alternate, lower voltage)
lithium (modern additive)

Cell Casing

nickel-plated steel box, rubber seals (Edison)
plastic box (modern commercial)
glass jars (demo projects)
pvc cylinders (Ed's Workshop)

Preliminary Figures for a 12V, 1kWh pile

NiFe cells produce a working potential of 1.2V, and charge at 1.4V. A 12V battery would then consist of 10 cells, and charge at 14V which is typical for most "12V" batteries.

To achieve 1kWh capacity, we will need 1000W/12V = ~85Ah. This means that each cell will need to provide 85Ah capacity. This corresponds to 1 coloumbs per second*3600 seconds per hour*85Ah*1/10^5 coloumbs per mole, which is approximately 3.17 moles of electrons. Iron is cheap and so is not a limiting factor. Nickel's electrochemistry in an NiFe battery indicates we get an electron per nickel atom, so 3.17 moles of nickel will be required with a hypothetical 100% utilization of active material. This is about 185g of Ni at a molar mass of 58.69g/mole. For a 'safety' margin, we will round up to 200g. At 200g Ni per cell, a total of 2kg of nickel will be needed for a 1kWh unit. The actual capacity of this cell based on the rounded values above would be 1095.8Wh.

Other important reactions in the cell

If you want a good battery rather than a poor one, the side reactions and other reactions in the cell are the most critical factor, with the only second being electrode geometry/design. They are a fundamental part of battery design. These exclude the reactions that contribute to the output electrical energy to the cell.

These are what sap energy away, leading to poor efficiency and high self discharge, and partly what limits battery life. Some of them are used to counteract the undesirable ones.

There are others that need to be learned from the documents listed in the sticking points section.

- tellurium dioxide is a recommended additive but never seems to be used in commercial batteries, improves efficiency by reducing hydrogen evolution.

- mucic acid is another additive that can be used to reduce the hydrogen evolution when integrated into the iron electrode, by a factor of 10 during storage (reducing self discharge greatly). Not clear if it helps improve efficiency as the patent does not mention that, but hydrogen evolution is the main reason the energy efficiency is so low so maybe worth further investigation.

-self discharge due to oxidization by dissolved o2 (pretty small in magnitude)

-The iron being anaerobically attacked by water, about 1000 times larger in magnitude than the oxidation due to dissolved o2. This is the main reason the battery has such a high self discharge rate. Basically the conversion of iron plus water to iron hydroxide plus hydrogen gas.

- self discharge at the nickel electrode, need to check the mechanisms/reactions again probably relatively low since it is in nimh and nicad despite the same reactants present.

-corrosion of the metallic mesh by electrolyte, this may be one of the lifetime-limiting reactions that increases with temperature.

-oxidization of sulfide to sulfate and it's ensuing accumulation on the surface of the iron electrode, increasing internal resistance. Sulfide is also often used to keep the iron electrode active so when it is used up the battery dies.

-sulfides like iron sulfide, or in some cases elemental sulfur (S8), or compounds of selenium or tellurium is used to "depassivate" the electrode. According to patents and reference sources this consists of reducing non-conductive, non-active oxides like FeO on the surface of the electrode back to active forms. They also indicate that without these additives charge efficiency drops greatly and hydrogen evolution goes way up, unless high purity iron like carbonyl iron is used and even then they don't work for long unless sulfur is added. No information has yet been found as of june 3rd 2011 on the performance of selenium and tellurium as mentioned above, if it might be superior to sulfur. Probably not.

-Accumulation of sulfur on the surface of the iron electrode esp. at lower temperatures and high discharge rates. If the sulfur or sulfides (or maybe other additives) are incorporated into the structure of the iron mass they are released faster when higher discharge rates occur and this can end up being too fast for them to diffuse away, resulting in them accumulating as a solid on the surface of the electrode, and since they are insulating and block access to the electrolyte this is a problem. At lower temps the solubility is lower so they are more prone to precipitate out of solution. This is not a permanent effect, the compounds redissolve if given some time. The exact temperatures and discharge rates depend on the quantities of additive involved and the surface are of the electrode etc. but references indicate this a problem more in the 0 deg C range than room temperature and at relatively high discharge rates, like two or three times the rated discharge rate (how high? In milliamps per sq meter is probably a reasonable measure).

-deposition of iron in the nickel compound crystal structure <--needs more research could be important life limiting reaction.

-oxidization of the surface of metallic flitts to low conductivity nickel oxide. Edison had a problem with nonconductive layer on the flitts forming and didn't know what it was, maybe explained in later patents.

-carbonate and the other one in the battery handbook undesirable ions, note that carbon dioxide from the air will react from the electrolyte to form carbonate salts <-- need to add those other ones. Some docs on the desired list may help inform here.

-probably all kinds of minor undesirable contaminants, Edison mentions manganese, and high purity material like carbonyl iron is often used to avoid them, and similarly for nickel electrode. However this may be expensive or harder to produce.

-lithium hydroxide apparently improves the thermodynamic reversibility of reactions (improves overall energy efficiency) and slows down the iron poisoning of the nickel electrode maybe this indicates longer life and higher charge/discharge efficiency, we need a chemist who can identify other ways of improving esp the charge/discharge efficiency by identifying other acceptable additives that might work. Also maybe analyze modern batteries if they have high performance.

-evolution of gasses at the nickel electrodes during charging and also charge-stand, this could play into the low efficiency but may only be commensurate with other prerequisite reactions at the iron electrode and unpreventable in themselves.

-The air interface one that causes oxidization of the nickel metal and/or active material(?) of the electrode when there is an interface with the electrolyte and air, nickel electrode needs to be submerged. Another cause of self discharge if not designed right, plus can corrode the electrode or the nickel plating of it right through possibly leading to failure.

- a couple of abstracts of inaccessible documents seem to clearly indicate that accumulation of potassium/sodium carbonate and similar compounds (presumably produced by atmospheric co2 and impurities in makeup electrolyte) deposit on the electrodes and this is one of the first problems that limits cell lifetime for unsealed, conventional nife batteries. They may be rejuvenated if this is the case.

Need to add references. See additives section too.

Toxicity

Nickel itself that is the concern rather than any particular compound. Water soluble compounds are unsurprisingly much more of a concern than metal that is bound in solid objects like nickel plating or some types of stainless steel, since it is more bioavailable and can be spread and spilled more easily. At low levels of exposure talking in terms of nickel content is done. But of course the exact solubility and other factors has a substantial effect on the exact toxicity at higher levels of different water soluble compounds too, note the ld50 is 10x lower for nickel chloride as for nickel oxyhydroxide according to the documents below, so the expedient of speaking in terms of nickel content doesn't always work that well.

Note that nickel hydroxide, oxide and oxyhydroxide are all considered "insoluble" although obviously the chemistry here depends on them being at least a bit soluble. But that increases the safety margin a bit. It may be substantially higher under these alkali conditions though.

Still all metals are toxic to some degree including iron and we need some numbers to make an informed decision. Preferably a solid evaluation of dose response relationship, and if the batteries are to be widely adopted now is the time to factor in chronic exposure too. It needs to be considered not in a vacuum but relative to other options available.

higher quality :

unknown due to lack of access:

Low quality:

http://www.crios.be/Nickel/toxicology.htm
material safety datasheets with information regarding nickel oxyhydroxide, clearly it is sometimes used as a material in NiMH, in fact most of the hits are datasheets for such batteries rather than the material itself:
http://www.rdbatteries.net/Data/Panasonic_NiMH_Info.pdf
http://www.chiefsupply.com/resources/msds/Moto-NiCd.pdf
http://www.batteriesplus.com/msds/Duracell_Nickel_Oxyhydroxide_%20Batteries_NorthAmericaMSDS.pdf (as if companies would give accurate information on their own products)
http://www.it.pg.com/productsafety/msds/fabric_and_homecare/duracell/Duracell_Nickel_Oxyhydroxide_Batteries_(North_America_MSDS).pdf

Note that the permissible exposure limits (PEL) for the material is about a fifth that of graphite, which we know is not too toxic though it might accumulate in the lungs I guess. Still there are a lot of variables there as most particles inhaled are not retained, depends on size etc etc.

Obviously the LD50 is quite low at 1000 mg/kg range. But that means little in terms of what happens at lower levels. For Chloride it seems to be in the 100 mg/kg range.

http://www.osha.gov/SLTC/healthguidelines/nickelsolublecompounds/recognition.html They fail to say dosages in critical places, this information is actually low quality.

nickel chloride: http://www.sciencelab.com/xMSDS-Nickel_chloride-9926213

oxide:http://www.inchem.org/documents/ukpids/ukpids/ukpid70.htm

From Dietary information perspective: http://iom.edu/Activities/Nutrition/SummaryDRIs/~/media/Files/Activity%20Files/Nutrition/DRIs/ULs%20for%20Vitamins%20and%20Elements.pdf

"A Tolerable Upper Intake Level (UL) is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects to almost all individuals in the general population. Unless otherwise specified, the UL represents total intake from food, water, and supplements."

1 milligram per day for nickel, 40 for iron. Well that's to totally zero adverse effect level and there's probably plenty of room for more there. Nickel is probably available as a dietary supplement, I wonder what happens when people take too much.

http://www.eoearth.org/article/Public_Health_Statement_for_Nickel case report little more than half way down of people drinking 250 mg/liter (250 ppm) nickel welding, relevant to pocket production: http://www.crios.be/Welding/toxicology.htm Maybe it woudl be better to make the pockets without welding. Folding perforated sheets cleverly, sewing with nickel wire etc. plenty of other options that should be fine .

As usual it is difficult to obtain quality information on a health issue and it is very time consuming to wade through the crap and get some answers. Case reports, vague qualitative statements, contradictions, and paywalls, are the norm. Ideally a table of dose-response relationships for a range of different people over a wide range of doses would be obtained but whatever.

In summary it looks like it is certainly less problematic than lead or mercury, gloves, ladling or scooping rather than pouring dry materials, and working outside would more than suffice for me personally. Spills of solutions and especially powders should be prevented.

Environmental Aspects

All batteries (at least the ones in common use) are toxic to a greater or lesser extent. The NiFe Battery isn't an exception, but it is far less toxic than Cadmium-based batteries.

Iron is non-toxic and commonly available.
Nickel is slightly toxic.
The electrolyte is caustic, but a so-called starved electrolyte cell can be used in a sealed battery without degradation in performance if potential spills are a perceived problem. In this design only the minimum amount of electrolyte is used, and it is absorbed in a porous mat so there is no liquid that can escape. This is what an Absorbed Glass Mat (AGM) lead acid battery is, and it can be used here too. The cost of the mat is not insignificant though. For photovoltaic there may be no need, flooded cells could be fine.
Increasing the viscosity of the electrolyte with glycerin also could be used, similar in theory to a gel-cell battery. There is a cost of increased internal resistance for a higher viscosity electrolyte. It may also pose a problem with the amount of gas produced, which needs to escape from the region of the electrodes. The glycerin might reduce cycle life as it could degrade on one of the electrodes in the strong red/ox environment or contain contaminants.
Glycerin is a by-product of creating bio-diesel, thus using a waste of a different process. It may have other uses elsewhere in producing the active materials etc. too.

Note on efficiency measures

The charge/discharge (also called round trip and overall) efficiency is the performance parameter that we care about, of course. Hypothetically it should be equal to the charge efficiency multiplied by the discharge efficiency. In this case the efficiency is energy efficiency.

The charge efficiency is often quoted in absence of the discharge or overall efficiency, which is very annoying as it makes it harder to compare different battery designs that are mentioned in the literature. In marketing materials it is probably used in the hope the customer will erroneously assume it is equivalent to overall efficiency, since it is always higher than overall.

The discharge efficiency is rarely referred to in isolation for some reason, probably because it usually more or less commensurate with charge efficiency and can be computed easily from the overall and charge efficiency. Commensurate does not mean equal though.

Not energy efficiency:

Faradaic and coloumbic efficiency: see wikipedia article. Unfortunately it is apparent in patents and other documents it is apparently that this is in fact often, either due to ignorance or more likely sloppiness, used to mean charge efficiency or overall efficiency so watch out for this.

Polarization of the electrodes, see wikipedia.

Overpotential, see wikipedia.

Non-chemical factors affecting performance

At low temperatures with some iron electrode designs sulfur can accumulate on the iron electrode and increase internal resistance (designs which incorporate elemental sulfur, patents indicate this can be rectified by using a sulfide salt of low solubility like iron sulfide FeS).

The conductivity of the electrolyte goes up as the temp goes up. This is desirable but other undesirable reactions increase in rate at higher temps so there is a compromise there. Also this is one of the main mechanisms that can lead to thermal runaway during constant voltage charging as it can form a positive feedback loop. The solution is to just not use constant voltage charging, which is easy.

The factors like the energy to weight ratio and power to weight will of course tend to be affected by any non-reactant materials used to e.g. reduce cost etc, but fortunately those are of relatively little importance in the context of OSE for off grid electricity and farm equipment, although they may be important for the electric car. Basically we want to produce something that can replace lead acid which is cheaper, easier to work with and make and maintain, more durable with abuse and longer lasting, and not as bad for the environment. Ideally both for starting lighting ignition (SLI) batteries and also storage. Batteries described in documents can handle 6C and more without seriously hard to manufacture materials and additives so SLI is definitely an option. See related pages section. None of these require high energy density or power to weight ratio although they are always nice.

The fraction of active material that actually is utilized if low will reduce power and energy to weight and volume ratio. Can be affected by particle size, additives and also any particles of active material that are not in reasonable electrical contact with the current collector for whatever reason will remain unused.

The level of the electrolyte can if not maintained in a non-sealed battery, drop below the level of the plates, and the uncovered portion of the plate may remain unused, decreasing capacity until the electrolyte is replenished.

There is always some distance that the current needs to travel to get from the reaction area to the current collector, and to do this is has to pass along the active material. Therefore the conductivity of the active material is an issue which significantly affects internal ohmic resistance (the term internal resistance is often used to refer in a catch all way to the current draw vs. voltage output relationship even though this is due to many factors besides ohmic resistance). See wikipedia for polarization for more information that relates to the voltaic efficiency.

For a vehicle: Power to weight ratio is affected strongly by the surface are to weight ratio of the electrodes.

The pressure the casing needs to stand increases as the internal pressure dose of course, see sealed battery section, if sealed it will need to stand significant pressure and therefore be relatively heavy.

Nickel iron for electric vehicles

There is some interest in using nickel iron in electric vehicles as it can produce major long term cost savings compared with some types of lithium. Also, as discussed on the battery comparison page there are only enough known lithium reserves to make roughly 3 million electric car batteries, nowhere near enough. So clearly some other battery technology will be needed, it is just a matter of which.

In contrast to photovoltaic system, obviously power to weight ratio and energy to weight ratio (specific energy) are paramount. Power to weight ratio for bursts during acceleration can always be improved using an ultracapacitor or other storage system in parallel however, but specific energy is a fundamental limitation.

As discussed above, the theoretical limitations of the chemistry for specific energy is 182.5 Wh/kg.

The practical weight is increased by a variety of factors mentioned in the non chemical factors that decrease performance section.

Wikipedia indicates around 50 Wh per kg for flooded cells, but those cells are not designed for low weight so that could be improved upon quite substantially.

Changhong uses nife pocket plate cells for starting batteries (SLI) so obviously they are capable of high rates though it is not clear how high. The starved electrolyte, sealed battery document mentions 6C at substantial efficiency loss. The ultimate electrode for both these ratios is the microfiber metal plaque, essentially nickel fibers around 2 microns wide assembled into a sheet with 95% porosity or so but that may not be needed.

One issue may be the relatively large amount of heat produced during charging, which may be twice or more that of lithium ion, therefore limiting the charge rate, but probably not a major issue.

There are quite a number of papers I have come across whose abstracts describe nife batteries being used to power electric vehicles for city fleets etc. and development projects of various sorts to develop nife batteries suitable for vehicles. It certainly works, it's jut a matter of achieving competitive performance. Zinc bromine may be more suitable for vehicle use, for a variety of reasons.

The discharge efficiency matters relatively more here as overall energy efficiency is less important that for photovoltaic systems probably. The lower it is, all other things being equal, the battery will weight more as the amount of energy stored is lower than what gets to the load, so you'd need a bigger battery.

Related pages

http://en.wikipedia.org/wiki/Nickel_iron_battery

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The Global Village Construction Set
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