cross-posted from: https://sopuli.xyz/post/1726805
RMIT engineers say they've tripled the energy density of cheap, rechargeable, recyclable proton flow batteries, which can now challenge commercially available lithium-ion batteries for capacity with a specific energy density of 245 Wh/kg.
It seems to be a hydrogen fuel cell with an integrated hydrogen atom store made of carbon, capable of absorbing 1% of its own weight in hydrogen.
This seems a little, but a mass unit of hydrogen contains a lot of molecules, so a lot of chemical energy (it is the lightest element after all). For example, 1 kilogram of hydrogen is 12 cubic meters at room temperature, so 1 gram is 12 liters - enough to do a lot of work, if reacted right.