Functional Cathode Coatings of LiH2PO4 and LiTi2(PO4)3 for Solid-State Batteries

Abstract

The interfacial reactivity and resistance between the cathode and the solid-state electrolyte (SSE) of a solid-state battery (SSB) usually lead to quite poor cycling performance and fast capacity decay. Hence, cathode coatings are generally applied to reduce cathode/SSE interfacial impedance in SSBs. In recent years, based on high-throughput screening, several promising coating materials have been recognized. In the present work, density functional theory calculations were conducted on LiH₂PO₄ and LiTi₂(PO₄)₃ to examine their characteristics as potential cathode coating materials. It was found that both of these materials had high oxidation potentials (>4.5 V), good chemical stability against the electrolyte and the cathode, reasonable ionic conductivity, and wide bandgaps; therefore, they can be used as outstanding cathode coating materials for SSBs.