Stabilizing LATP Electrolyte Interface of All-Solid-State Lithium Ion Batteries Consisting of High-Voltage Cathode

Abstract

NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte has been investigated because of its stability in the air and water and wide electrochemical window, which make it a suitable electrolyte material to be used with a high-voltage cathode material. However, LATP solid electrolyte has interfacial problems, as in LiCoO2/LATP results in a limited contact area and Li/LATP suffers from structural collapse due to side reactions.In the present study, we inserted PEO polymer electrolyte to suppress the Li/LATP interface side reactions and mitigate the LiCoO2/LATP interfacial resistance. We prepared symmetric & full cells with PEO coated on both sides of electrolyte. The symmetric cell consisted of Li/PEO/LATP/PEO/Li and full cell consisted of Li/PEO/LATP/PEO/LiCoO2. The symmetric cell exhibited stable cycling behavior at current density 0.1mA/cm2 for 2000h at 60℃. The full cell charge capacity showed 151.71mAh/g in voltage range of 3.0~4.2V at 60℃ at 0.1C rate. Therefore, PEO protecting layer is effective for stable cycling performance. Keyword: All-solid-state Batteries, LATP Solid Electrolyte, Li/LATP Interface, LiCoO2/LATP Interface, PEO polymer electrolyte