Hydroborate-Based Solid Electrolytes for All-Solid-State Batteries

Hydroborates, i.e. ionic salts of boron-hydrogen compounds, are an emerging material class of solid electrolytes for all-solid-state batteries. In particular, some of the metal hydroborates (≠ neutral hydroboranes) featuring three-dimensional anion clusters exhibit exceptional thermal and (electro)chemical stability, and liquid-like ionic conductivity with a unique ion conduction mechanism. These characteristics enable the fabrication of competitive all-solid-state cells with stable battery cycling performance. This chapter reviews the attractive material properties of hydroborates and their implementation as highly conductive solid electrolytes in all-solid-state batteries.