Recharging underwater robots is hard Getty

Underwater robots could get their batteries recharged by munching the sea floor. A device created by the US Navy extracts electrical energy from layers of fish faeces and other organic matter to provide an endless source of power.

All underwater devices have a fundamental limitation – battery life. They are incredibly useful for exploring and monitoring the depths, but once their power reserves start to run low there’s no choice but to bring them to the surface or abandon them.

One approach to solving this is microbial fuel cells (MFCs) that use the sea …