[cloudwalking]

Atomic isotope? Would be even worse for tech waste, but imagine the 'battery' life. 25 years...

[biot]

Ideally you'd have a removable power module which you can take from device to device... a "zap drive". Brought to you by the US Nucleics Corporation.

[light3]

They can be shaped as coins and become a new currency, it glows green when fully charged. Devices(including cars) have coin slots to take in power.

[Herring]

Spoken like a true geek. Normal people don't want to know that such things even exist. Let machines with radiation detectors track them down in the dumpsters.