Scientists at the University of Cambridge in conjunction with ARM have managed to run a small computer for an entire year using only Algae. They believe applications could remove the need for batteries in small electric devices, such as your smartwatch. The small computer used ARM’s Cortex M0+ processor which is currently widely used to power similar small devices.
A world without need to dive through your cupboards for a AA battery, or a smartwatch with a battery that dwarfs current lifespans. The applications for something like this are so wide reaching and is only one of the ways that researchers are working on to end our need for non-replaceable batteries