Unexpected discovery leads to a better battery

pnnl.gov

16 pointsnielsbjerg4 comments

The specs read a little oddly: "... operating voltage of 1.44 V, a capacity of 285 mAh g−1 (MnO2), and capacity retention of 92% over 5,000 cycles"

That looks like it is (410Wh/kg) roughly 3x the capacity by weight of the best available currently lipos. Am I reading that correctly?

Got it - the actual paper cites it as 285 mAh g^-1 ie 285 mAh/g, so it does indeed look like ~410Wh/kg.

The nature article has a nice chart that doesn't need access: http://www.nature.com/article-assets/npg/nenergy/2016/nenerg...

Looks like at 5C discharge rate they can maintain 92% of their capacity ~375 Wh/kg even after 5000 cycles - this is the most promising stuff I've seen since Li-S (lithium sulphur), which have a higher specific energy, but lower cycle life and much lower discharge rating.

The nominal voltage of a LiFePO battery is 3.2V (or 3.6V for other types).

MnO2 -> 1.44V * 0.285mAh/g = 0.41Wh/g

LiFePO -> 3.2V * 0.170mAh/g (from what I could find online) = 0.533Wh/g

I could be wrong, but I think production lipos (and variants) are closer to .15Wh/g, and not much higher than 0.25 for anything that isn't entirely theoretical.

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