Lithium-ion Battery Solid Electrolyte Offers Safety

Japan’s Nihon Keizai Shimbun reports that a group from Tokyo Metropolitan University and Nippon Soda Co. has developed a lithium-ion battery with a solid electrolyte that is both safer and provides better performance than current technology.

Because of the danger of Li-ion batteries overheating and catching fire, an effort is on to develop high-performance solid electrolyte materials that can replace the organic solvents now used for the batteries.

The new solid electrolyte is made from a combination of polyethylene oxide, for fast transfer of lithium ions, and polystyrene, for high mechanical strength. By linking these two molecules, the researchers succeeded in fabricating an electrolyte material that is several microns thick and exhibits high performance without sacrificing strength.

A prototype battery made by sandwiching this solid electrolyte between electrodes exhibited the highest power output density per unit weight of any lithium-ion battery, equal in charge-discharge performance to the nickel-hydrogen batteries now used in hybrid cars. Since the battery also has double the charge capacity per unit weight of these nickel-hydrogen batteries, it could help lower hybrids’ weight and boost their fuel efficiency. The goal is to have a practical version of the new solid electrolyte lithium-ion battery ready for hybrid cars in three or four years.