Scientists develop non-flammable electrolyte for lithium-metal batteries

Electric car. (Reference image by Kindel Media, Pexels.)

Using computational science, researchers at the Korea Institute of Science and Technology (KIST) and the US Lawrence Livermore National Laboratory have developed a fluorine-substituted high-voltage stable chloride-based solid-state electrolyte.

This new material is expected to be non-flammable and a safer alternative to liquid electrolytes commonly found in lithium-ion batteries.

To improve the high-voltage stability of chloride-based solid electrolyte (Li3MCl6), the research team proposed the optimal composition and design principle of chloride-based solid electrolyte (Li3MCl5F) substituted with fluorine(F), which has strong chemical bonding ability.

For the proposed strategy to achieve this goal, LLNL contributed by utilizing their cutting-edge supercomputing resources for calculations and subsequent experimental validations were conducted at KIST. The collaborative research team adopted a cost-effective and time-saving strategy, wherein computational science guides the initial material design, followed by rigorous laboratory validation.

The chloride-based solid electrolyte synthesized based on the design principle proposed by the team was applied to an all-solid-state battery to evaluate its electrochemical stability under high-voltage conditions. It showed high-voltage stability exceeding 4 V, comparable to that of commercial lithium-ion batteries with liquid electrolytes. Accordingly, fluorine(F)-substituted chloride-based solid electrolytes are expected to replace sulphide-based solid electrolytes that are unstable at high voltages, accelerating the commercialization of all-solid-state batteries.

The Korea-US joint research team will now conduct follow-up research on the synthesis process of the material, alongside the optimization of electrode and cell manufacturing processes. These concerted efforts aim to hasten the commercialization of all-solid-state batteries.

In the event of successful commercialization, the joint team will be able to capture the market for solid-state electrolytes, a key component of all-solid-state batteries, in the US, one of the largest consumers of secondary batteries such as energy storage systems and electric vehicles.

“This work provides a new design principle for fluorine-substituted high-voltage stable chloride-based solid-state electrolytes, which will accelerate the commercialization of high-energy-density next-generation lithium all-solid-state batteries without fire hazards,” Seungho Yu, one of the researchers at KITS, said in a media statement.