SnO2 oxide cathode coating: The key ingredient for bi-based polymer quasi-solid-state batteries, enabling stable cycling of high-voltage solid-state LiNi0.5Mn1.5O4/lithium metal battery

Abstract

The solid electrolytes are strongly considered as the next-generation electrolyte due to the natural safety compared with liquid electrolyte, however, the overall low-rate performance of all-solid-state batteries and large internal resistance have hindered the development of all-solid-state batteries. In this paper, SnO2 is grown in situ on LiNi0.5Mn1.5O4 (LNMO) to increase the specific capacity and stabilize the cycle performance. After the preparation of the cathode material, it is assembled with the solid electrolyte slurry prepared by PMMA-PVDF @ Li1.3Al0.3Ti1.7(PO4)3(LATP) to form an all-solid-state battery, which has good electrochemical performance, even at high rates. At a test temperature of 60 ℃, the initial specific capacity obtained at 0.2 C is 125 mAh·g−1. After 100 cycles, it drops to 105 mAh·g−1, with a capacity decay rate of 94.2 %, and the initial specific capacity at a rate of 0.5 C. After being 110 mAh·g−1, 500 cycles, the specific capacity remains at 95 mAh·g−1. The excellent performance of coating LNMO depends on the binding of SnO2 to Mn+. The good catalytic effect enables the high specific capacity of SnO2 and the high voltage window of LNMO to be displayed. After the coating of tin dioxide, the interface contact between the positive electrode and the solid electrolyte is improved. The appearance of SnO2 reduces the interface impedance of the quasi-solid-state battery from 276 Ω to 243 Ω. At the same time, the generation of space charge layer is suppressed. Combined with the prepared dual matrix [email protected], the working environment and cycle stability of the all-solid-state battery are improved, and the development of the all-solid-state battery is promoted.