Covalent interfacial coupling for hybrid solid-state Li ion conductor

Solid electrolyte is the key component of any practical solid-state batteries. Although inorganic Li₃PS₄ electrolyte has been widely studied, this material is highly unstable in air, reactive towards Li metal, and difficult to process. These undesirable features have limited its application in solid state lithium batteries. In this work, a hybrid solid state electrolyte composed of β-Li₃PS₄ and poly(glycidyl methacrylate) is prepared through a controlled interfacial reaction between the polymer and the Li₃PS₄. The resulting hybrid electrolyte shows a good processability, i.e. it can be processed through simple slurry coating rather than conventional cold pressing or high-temperature sintering techniques. Furthermore, it exhibits improved air stability and decreased interfacial resistance with metallic lithium as compared with pure Li₃PS₄ electrolytes. More interestingly, this hybrid electrolyte exhibits a high ionic conductivity of 1.8 × 10⁻⁴ S/cm at room temperature, which is even slightly higher than the ionic conductivity of the pure β-Li₃PS₄. The new type of hybrid electrolyte will be highly promising for future applications in solid state batteries.