Quantum coating makes button batteries childproof

BBC : Each year in the US, more than 3000 button-shaped batteries are ingested, primarily by children. When exposed to the fluids of the digestive system, batteries can release current and set off chemical reactions that can seriously injure or kill the person. To prevent that happening, Jeff Karp of the Brigham and Women’s Hospital in Boston and his colleagues have invented a coating that keeps the batteries from generating current unless squeezed. They covered the negative terminal of the battery with a 1-mm-thick layer of silicone laced with small particles of metal and then covered the rest of the battery with a sealant. When the battery is squeezed, the silicone compresses and the metal particles get close enough to allow the electrons from the battery to flow through the material via quantum tunneling. They compared the battery’s behavior with that of an uncovered battery by placing each in a beaker of simulated stomach fluid. They also tested the covered battery in the digestive systems of live pigs.