God I hope this is not another vaporware battery story.
Nuclear battery produces power for 50 years without needing to charge
Comments ( https://news.ycombinator.com/item?id=38989690 )
https://www.independent.co.uk/tech/nuclear-battery-betavolt-atomic-china-b2476979.html
Discussion
I doubt it's true. Betavoltaic batteries don't do more than a few mW. They are super cool for things like sensors and low power IoT devices, but things like smartphones are simply too much.