Very interesting company. They started with a way to produce graphene at scale, then went looking for something to do with it. Their first idea was to use it as a cement additive. They have since used it as friction reducer in engine oil, and are selling it in Australia, Canada, and soon the US, as a radiator coating to improve HVAC performance.
Yes, you can get rechargeable lithium batteries in the standard form factors like AA or AAA. They should work for most things, but the voltage is a bit different and of course you must use the right charger. They’ve been out for quite a few years and even the main brands sell them now