Paul van Gerven
22 October

Cutting a commercial lithium-ion battery in half isn’t a good idea, especially if you intend to subsequently put a blowtorch to it. In the future, however, you might be spared the fire or explosion that would normally result because researchers from Johns Hopkins Applied Physics Laboratory developed a completely non-toxic and non-flammable electrolyte for lithium-ion batteries.

Johns Hopkins APL

The electrolyte is, surprisingly, water-based. Normally, that wouldn’t be compatible with widely used lithium titanate anodes, as the lithium would react with the water. By ‘confining’ the water in a polymer gel, that reaction no longer proceeds at an appreciable rate when electrolyte and anode are brought into contact.

The electrolyte itself is prepared by polymerizing an aqueous solution of lithium salts and precursor molecules, which results in a fairly solid but flexible gel, akin to a contact lens. A battery using the film as an electrolyte works in the open air for days and keeps working even after burning, cutting or stressing the device in other ways.