Directly Using Li₂CO₃ as a Lithiophobic Interlayer to Inhibit Li Dendrites for High-Performance Solid-State Batteries

Abstract

Garnet solid electrolytes have attracted great interest due to their wide electrochemistry window and high ion conductivity. However, the lithiophobic Li2CO3 generated on the garnet surface results in a huge interfacial resistance and interface incompatibility. Herein, different from the extensive removal or conversion strategies, the Li2CO3 on the surface of Li6.5La3Zr1.5Ta0.5O12 (LLZTO) is directly used as a lithiophobic layer to suppress Li dendrite growth, and the lithophilic Li-In-F composite is used as the anode. The Li symmetrical half-cell with a Li2CO3 interlayer is stably cycled for 6500 h without Li dendrite formation, a much longer time than for the half-cell without a Li2CO3 interlayer (2334 h), showing a much higher interfacial stability. Moreover, the full cell based on LiFePO4 and LiNi0.8Co0.1Mn0.1O2 cathode shows a stable cycling performance and high rate capability (LiNi0.8Co0.1Mn0.1O2, 94%@100th cycle@1C; LiFePO4, 90%@500th cycle@2C). This study provides a distinct way of converting disadvantages into advantages and solving the Li|LLZTO interfacial issues.