All-in-one improvement toward Li₆PS₅Br-Based solid electrolytes triggered by compositional tune

Abstract

Sulfide solid electrolytes possess high ionic conductivity and moderate dendrite suppression capability, but rather poor compatibility against oxide cathodes and metallic Li. Here, we report O-doped Li₆PS₅Br as solid electrolyte synthesized by a facile solid-state sintering. Different from other O-incorporated sulfides, the O atoms in Li₆PS_5-xO_xBr prefer to substitute the S atoms at free S²⁻ sites rather than those at the PS₄ tetrahedra. Remarkably, without deteriorating the ionic conductivity, this inorganic solid electrolyte with O doping exhibits comprehensively enhanced properties including excellent dendrite suppression capability, superior electrochemical and chemical stability against Li metal as well as high voltage oxide cathodes, and good air stability. Li(Ni_0.8Co_0.1Mn_0.1)O₂ and LiCoO₂-based all-solid-state batteries with Li₆PS_4.7O_0.3Br electrolyte deliver high specific capacity, superior rate capability, and outstanding cycling stability accompanied with low interfacial resistivity. This type of inorganic solid electrolytes is promising for all-solid-state batteries with high energy density.