All-solid-state Li battery with atomically intimate electrode–electrolyte contact

Abstract

Creating epitaxial interfaces has recently been discovered as an effective strategy for addressing the electrode–electrolyte contact issue in all-solid-state Li batteries. The solid–solid composite electrode fabricated using this approach not only exhibits atomically intimate solid–solid contact but also possesses excellent tolerance to repeated cycling. Nevertheless, so far such epitaxial composite electrodes have only been cycled in cells with liquid-electrolyte-soaked separators, instead of all-solid-state cells, because realizing a thorough contact between the epitaxial composite electrode and the solid-electrolyte separator layer is difficult. Here, an all-solid-state cell with decent cycling performance was constructed using the epitaxial composite electrode. By infiltrating the Li4Ti5O12–Li0.33La0.56TiO3 ceramic pellet with a poly(ethylene oxide)-based solid electrolyte, a flat, non-porous surface that can effectively contact the separator layer is created. When integrated into an all-solid-state Li4Ti5O12–Li0.33La0.56TiO3 | Li6PS5Cl | Li13Si4 cell, this composite electrode was stably cycled for 100 cycles under 0.1 C at 80 °C with a final discharge capacity of 174.5 mAh g−1.