

Almost nothing… Maybe some very basic scientific equipment, but they do note that they’d be able to use multiple batteries layered to produce higher output, and that they’re expecting to have a 1 watt version later this year; that’d be far more useful in practice.
That’s a good point; it becomes less economical if you need multiple of these cells just to counteract the self-discharge. Even so, it’s really just a demo of the technology; they do mention they expect to have a 1 watt model later this year.