h a l f b a k e r yRIFHMAO
(Rolling in flour, halfbaking my ass off)
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The battery comprises an iron plate serving as an anode, a (probably tin coated) graphite cathode, and sodium hydroxide as an electrolyte. During charging, sodium ions would migrate to the cathode and become intercalated into it, whilst hydroxyl ions would react with the iron to form iron hydroxide.
When the battery is discharging, this would occur in reverse.
The advantage this battery has is that the materials needed to produce it are all incredibly cheap. The disadvantage is that it may not work. I really have no idea. Low capacity isn't an issue if the cost is low enough, since they would only be used for stationary applications anyway.
NiFe batteries
https://ironedison.com/
[beanangel, Jan 11 2018]
A Nation-Sized Battery
https://dothemath.u...tion-sized-battery/
Do the math on the battery options available [Selky, Jan 11 2018]
Global Village Construction Set
http://opensourceecology.org/gvcs/
Open Source Ecology page [Selky, Jan 11 2018]
Cellulose anode
http://www.kurzweil...onmentally-friendly
Anode, cathode... current should flow with electrons, dammit [Selky, Jan 11 2018]
Table of Electronegativities
http://www.thecatalyst.org/electabl.html
As mentioned in an annotation. [Vernon, Jan 11 2018]
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Annotation:
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// The disadvantage is that it may not work // |
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Sp. "The disadvantage is that it will not work" or "The disadvantage is that it can not work". |
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Valid only if true. I don't know if it's true, so 'may' is the correct word to use. |
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Given that the electrode potentials of iron and sodium differ by about 2.4V, why would this not work? |
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It interesting to think of a new battery technology but it
would be better if you could describe a use where this
battery is really optimal. Pb/SO4 might cheaper. Na might
be explosive. but that does not mean it does not have a
niche application I cannot think of. |
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Replacing Pb at off grid applications are Nickel-Iron
batteries. These might be cheaper than NaFe batteries |
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[beanangel], the problem with nickel-iron and lead acid batteries is that nickel and lead are too scarce for us to be able to rely on solar power. An additional problem is the high lifetime cost of lead acid, and the poor efficiency of nickel-iron. See A Nation-Sized battery for details. Given that, I've been looking at and thinking about batteries that use materials which are abundant, such as sodium and iron. Sodium ion is promising (and they can work with cellulose electrodes!), and I'm thinking of ways that they could be made to work in as part of the Open Source Ecology Global Village Construction Set, in place of the NiFe batteries they're planning for at the moment. Lye is abundant, and so are cellulose and iron. |
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NiFe batteries show that we can cycle between Fe and Fe(OH)2 a very large number of times, so if such a battery worked, the lifespan would be determined by the cathode. We could perhaps make ones which could be switched out when they fail. Low cost disposable ones of cellulose and tin. |
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NiFe's are expensive compared to Pb. Better power to weight, slightly worse in/out efficiency. |
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They really can't be broken and last forever in any state - charged, uncharged, whatever. |
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Which makes them a good fit for applications where it's very optimal to install the half a ton of batteries once and only once. |
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I'm pretty sure that a functioning battery can be made from
almost any two metals that have different
electronegativities (see linked table). |
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However, we want recharge-able batteries, and that's the
rub. Designing the system to allow recharging also means
controlling how metal electrodes are dissolved and
reformed. Most recharge-able batteries eventually fail
because of imperfections in that process, not the basic
electrochemistry. |
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// a functioning battery can be made from almost any two metals that have different electronegativities // |
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This is correct; it's as simple as taking a copper wire and a zinc wire and inserting into a citrus fruit to yield electric potential difference, giving rise to the famous phrase "A lemon entry, my dear [Vernon]*" |
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*In fact, Holmes never says "Elementary, my dear Watson" in any of the stories; it first occurs in the script of a stage adaptation. |
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The Global village construction set site was interesting.
Na ion/Fe could work, so you have an upvote. |
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An entry, or an entrance ? |
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The difference is subtle, but important. |
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