NASICON-type Li_1.3Al­_0.3Ti_1.7(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