The development is timely following UK's Civil Aviation Authority (CAA) recent declaration that the huge growth in people carrying lithium batteries on aircraft is posing a growing fire risk. Led by Katie Zhong, Westinghouse Distinguished Professor in the School of Mechanical and Materials Engineering, the researchers reported on their work in the journal, Advanced Energy Materials.
The biggest potential risk for high performance lithium batteries comes from the electrolyte in the battery, which is made of either a liquid or gel in all commercially available rechargeable lithium batteries. The liquid acid solutions can leak and pose a fire or chemical burn hazard.
"While commercial battery makers have ways to address these safety concerns, such as adding temperature sensors or flame retardant additives, they "can't solve the safety problem fundamentally," explained Zhong.
Solid electrolytes tend to not conduct electricity well and are difficult to connect to the anode and cathode so the Washington State University research team began looking for a material that would work as well as liquid and could stay attached to the anode and cathode - "like when you get chewing gum on your shoe," suggested Zhong.
The gum-like lithium battery electrolyte the researchers have filed a patent on is claimed to be twice as sticky as real gum and adheres well to the other battery components.
The material contains a liquid electrolyte that hangs on solid particles of wax or a similar material. Although a current can travel through the liquid parts of the electrolyte the solid particles act as a protective mechanism. If the material gets too hot, the solid melts and easily stops the electric conduction and lessens the fire hazard risk. The electrolyte material, which could be used in future flexible electronics, is also flexible and lightweight and should be easy to assemble into commercial battery designs.
The researchers say the gum-like material can be stretched, smashed, and twisted but will still continue