A group of scientists from Iowa State University has developed a self-destructing battery that dissolves in water. Creating devices that could perform a variety of functions until exposed to light, heat or liquid is a relatively new field of study called ?transient electronics.? Future applications include keeping military secrets out of enemy hands as well as saving patients the pain of removing a medical device.
http://futurism.com/scientists-develop-self-destructing-batteries-that-dissolve-in-water/