Chinese Researchers Explore Batteries Powered by Body Fluids 

From Go ahead and cry — your tears might power the batteries of the future – The Verge

In a lot of the flexible batteries out there, these electrolyte solutions are made out of strong acids or toxic chemicals, the study says. That stuff is corrosive, flammable, or toxic, and you definitely don’t want it dribbling onto or into your body. That’s why scientists at Fudan University in China came up with a way to replace these toxic electrolyte solutions with something much less harmful.

The researchers experimented with a few different types of electrolyte solutions. The one that worked best was sodium sulfate, which is sometimes used as a laxative. But saline solutions, which are literally diluted salt water, also worked well. Eventually, bodily fluids like blood, sweat, or tears might take over the roll of the electrolyte solution to power medical implants, the study says.