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Silver-zinc batteries are in the news (the pop science news) these days because they are being researched to compete with lithium ion batteries. But the price is high because silver is expensive. So it got me thinking about copper.

Just quoting the values as given by wikipedia:

Copper has an electronegativity of 1.9 and resistivity of 16.78 nΩm.

Silver has an electronegativity of 1.93 and resistivity of 15.87 nΩm.

They seem really similar. Can't the copper-zinc chemistry substitute for the silver-zinc chemistry? Wouldn't this have similar performance in a battery (either primary or rechargeable)?

I'll finally note that copper-zinc is one of the oldest battery chemistries ever built, all the way back in 1800 by Alessandro Volta. So I'm suspicious that there's something not so great about it (or otherwise silver-zinc wouldn't be needed). I just don't know what it might be.

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    \$\begingroup\$ A little off on your oldest battery by about 2,000 years... corrosion-doctors.org/Batteries/Baghdad-Battery.htm It's iron-copper btw \$\endgroup\$
    – Trevor_G
    Sep 21, 2017 at 18:12
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    \$\begingroup\$ @Trevor Okay, I'll edit. \$\endgroup\$
    – DrZ214
    Sep 21, 2017 at 18:25
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    \$\begingroup\$ Their electropotentials, however, (which is the criterion you need to care about) are fairly different, especially if you consider all their forms. \$\endgroup\$ Sep 27, 2017 at 21:57
  • \$\begingroup\$ Another alternative would be to silver plate the copper cathode instead of using solid silver. \$\endgroup\$
    – Nicalandia
    Mar 12, 2019 at 14:39

2 Answers 2

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During the charging process, silver is first oxidized to silver(I) oxide: 2Ag(s) + 2OH− → Ag2O + H2O + 2e− and then to silver(II) oxide: Ag2O + 2OH− → 2AgO + H2O + 2e−, while the zinc oxide is reduced to metallic zinc: 2Zn(OH)2 + 4e− = 2Zn + 4OH−.

AgO and Ag2O i stronger oxidant than Cu2O and CuO, so they can reach higher voltage from cell. You have to look at Standard electrode potential: https://en.wikipedia.org/wiki/Standard_electrode_potential_(data_page) You can build copper oxide - zinc battery, but it have only some about 0.8V per cell (but have strong current capability).

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  • \$\begingroup\$ Thanks for that link. It brings up an interesting point. I've often heard the silver batteries called either "silver-oxide" or "silver-zinc". I think oxides must play a part in both of them, but it begs the question of where the zinc is. I get the impression that it's just a catalyst. I also investigated gold-oxide, just to try the first 3 elements in the column: copper, silver, gold. But it looks like gold is about the same electrode potential as silver, maybe even a little worse, and of course is much heavier and more expensive than silver. \$\endgroup\$
    – DrZ214
    Sep 29, 2017 at 16:17
  • \$\begingroup\$ Zinc metal is the anode and AgO is the cathode. See the wikipedia article on silver zinc batteries. The zinc and copper Daniell cell has no relationship to the silver zinc cell. \$\endgroup\$
    – Ed V
    Jul 21, 2019 at 16:21
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I think this has something to do with the discharge curve.On wikipedia it is stated that mercury-oxide batteries have a flat discharge curve, and that silver-oxide batteries have an even flatter one.According to another source copper oxide batteries don't always have a flat discharge curve.The voltage sometimes drops during the discharge, making these batteries less practical.I believe this is the reason why copper-oxide batteries are not mass produced even though they have high capacity.

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