Comment by z_ack

It's not matter of skepticism, it can't work and it's matter of science, it doesn't work both as generator to "recharge" the battery (at microwatt scale it needs years ) and as generator to directly power "phones or drones", thing they declare, to do that you should employ very "hot" isotopes and if we don't count other factors that discourage that solution, the shielding, we are talking about centimeters of solid lead, make the same solution impractical. I don't think people want a 2kg phone large as a toaster. Isotope based batteries are only good for space satellites and probes and there is no way to "miniaturize" them at a scale you can use in a phone, principal reason is radiation: to produce significant energy to power "phones or drones" or to recharge the battery you needs high radiations that means thick shielding.