Ion Storage Systems Says Its Ceramic Electrolyte Could Be a Gamechanger for Solid-State Batteries
A superthin electrolyte with three layers could deliver safe, fast-charging batteries
For years, experts have predicted that solid-state batteries will be the next-generation technology for electric vehicles (EVs). These batteries promise to be safer by relying on a solid electrolyte instead of the flammable liquids used in today’s lithium-ion batteries. They could also last longer and weigh less, with a 10 times higher energy density, because they use a lithium metal anode instead of graphite.
Ford, Hyundai, Nissan, Toyota, and Volkswagen are all investing in solid-state battery research. And startups in the space abound.
But Eric Wachsman says his company, Ion Storage Systems, stands out for a few reasons. The company’s strong, dense ceramic electrolyte is only about 10 micrometers thick, which is the same thickness as the plastic separators used in today’s lithium-ion batteries, and it conducts lithium ions as well as current liquid electrolytes. And according to Wachsman, it overcomes two key issues with solid-state batteries: high electrolyte resistance and a low current capability.
The electrolyte has three layers. In the middle is a thin, dense layer of the lithium-oxide ceramic (with the chemical formula: Li7La3Zr2O12). On either side of that layer is a slightly thicker porous layer of ceramic with a superthin aluminum oxide coating that further reduces resistance.
Ceramics can be brittle. But the dense middle layer adds strength. It also makes the battery safer by blocking dendrites, which are tiny needles that can grow when lithium ions deposit on the anode unevenly, piercing the thin plastic separators in today’s cells and causing a hazardous short circuit. And the porous, aluminum oxide-coated layers allow lithium ions to move quickly into the electrolyte.
“It really comes down to the unique structure and interfacial treatments that allow us to get very low resistance,” Wachsman says. “High resistance has been the hang up for solid-state batteries.”