@Brainship I did mean the chemistry of them but they are also really good as energy storage devices too! though the material to make them is not so environmentally friendly, especially the old nickel-cadmium ones or lead-acid ones, though lithium mining isn't the friendliest either

@Felthry that is sadly the issue with batteries.

I do hope more environmentally friendly forms of small scale energy storage can be found—although it is likely they are being worked on somewhere.

@Brainship there's work on sodium-ion batteries that would be both a lot cheaper (there's a ton of sodium easily obtained from basically anywhere) and more environmentally friendly (at least if they can manage to not need any other exotic materials)

@Brainship They don't currently work very well though. I think the best ones so far had a pretty tiny capacity and could only be recharged about six or seven times before they stopped working completely (this is comparable to the number of times you can recharge an alkaline battery if you're very careful about it) (do not try to recharge an alkaline battery. you technically can but they tend to explode when you try to)