Researchers at Yonsei University have developed a fluoride-based solid electrolyte that addresses a key challenge in advancing next-generation electric vehicle (EV) and energy storage batteries: achieving high voltage and energy density without compromising safety.
The new material, LiCl–4Li₂TiF₆, allows all-solid-state batteries (ASSBs) to operate reliably beyond five volts while maintaining high ionic conductivity and thermal stability.
Illustration of the LiCl-4Li2TiF6 solid electrolyte shielding high-voltage spinel cathodes in a next-generation all-solid-state battery.
This combination could enable longer driving ranges, improved durability, and reduced fire risk in future EV platforms.
Most existing solid electrolytes, such as sulfide and oxide systems, degrade above four volts, limiting their ability to power high-performance applications. The Yonsei team’s fluoride formulation remains stable beyond five volts and exhibits a Li⁺ conductivity of 1.7 × 10⁻⁵ S/cm at 30° C, one of the highest in its class.
When paired with high-voltage spinel cathodes, such as LiNi₀.₅Mn₁.₅O₄ (LNMO), the electrolyte supports efficient cycling and retains over 75% capacity after 500 cycles. The system also achieves an areal capacity of 35.3 mAh/cm², setting a new benchmark for solid-state configurations.
The electrolyte acts as a bulk ion conductor and a protective interface layer, preventing chemical reactions that typically degrade performance at the electrode interface. Its compatibility with cost-effective halide catholytes, including Zr-based systems, supports scalability and lower material costs for commercial production.
By combining high voltage, long cycle life, and intrinsic safety, this research marks an important step toward practical solid-state batteries for electric vehicles and large-scale renewable energy storage. The study, led by Professor Yoon Seok Jung at Yonsei University, was published in Nature Energy on October 3rd, 2025.
Filed Under: Batteries, Technology News