Self-charging battery generates electricity from moisture in the air.
'Australian company Strategic Elements wants that energy back, and it's working with the University of New South Wales and the CSIRO to develop a flexible, self-charging battery technology that harvests electrical energy from moisture in the air to directly power devices without ever needing to plug them in.'
(New Atlas, Melbourne) >

https://newatlas.com/energy/strategic-elements-self-charging-battery/