Hybrid solid electrolytes with excellent electrochemical properties and their applications in all-solid-state cells

Abstract

Three types of inorganic electrolytes [Li10GeP2S12 (LGPS), 75Li2S·24P2S5·1P2O5 (LPOS), Li1.5Al0.5Ge1.5(PO4)3 (LAGP)] with different particle sizes and electrochemical properties are selected as active fillers incorporated into poly(ethylene oxide) (PEO) matrix to fabricate hybrid solid electrolytes. The optimum composition of each filler is found in consideration of ionic conductivity. Their electrochemical characteristics are investigated. The optimal conductivities are 1.60 × 10−5, 1.18 × 10−5, and 2.12 × 10−5 S cm−1 at room temperature for PEO-1%LGPS, PEO-1%LPOS, and PEO-20%LAGP, respectively. The electrochemical stability windows of these hybrid solid electrolytes are all above 5 V (vs. Li+/Li). The results show that these fillers have positive effects on the ionic conductivity, lithium ion transference number, and electrochemical stability. The relationship between the type of filler and electrochemical properties has been investigated. All-solid-state cells LiFePO4/Li are fabricated and present fascinating electrochemical performance with high capacity retention and good cycling stability. This work provides promising electrolytes prepared by a simple method.