Hydrogen-Rich Argyrodite Solid Electrolytes for NCM/Li All-Solid-State batteries

Argyrodite-type ionic conductors have received significant attention as solid electrolyte systems for all-solid-state batteries due to their high ionic conductivity, mechanical deformability, and processability. However, they often suffer from insufficient rate and cycling performance with high-energy-density metal electrodes, mainly due to chemical and electrochemical instability at low potentials. Herein, we report that incorporating BH 4 – into the argyrodite structure enhances both lithium ion conductivity and low potential stability. Based on these results, we also develop high-voltage all-solid-state batteries that are reversibly cycled with a high-Ni-content oxide cathode and a lithium metal anode, employing two different argyrodite-type solid electrolytes as the catholyte and anolyte, respectively. The current study suggests that many hydride anions could be promising candidates as coexisting anions in the solid electrolytes of emerging all-solid-state batteries that need to deal with low potential stability.