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

Garnet solid electrolytes have attracted great interest due to their wide electrochemistry window and high ion conductivity. However, the lithiophobic Li 2 CO 3 generated on the garnet surface results in a huge interfacial resistance and interface incompatibility. Herein, different from the extensive removal or conversion strategies, the Li 2 CO 3 on the surface of Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (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 Li 2 CO 3 interlayer is stably cycled for 6500 h without Li dendrite formation, a much longer time than for the half-cell without a Li 2 CO 3 interlayer (2334 h), showing a much higher interfacial stability. Moreover, the full cell based on LiFePO 4 and LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode shows a stable cycling performance and high rate capability (LiNi 0.8 Co 0.1 Mn 0.1 O 2, 94%@100th cycle@1C; LiFePO 4, 90%@500th cycle@2C). This study provides a distinct way of converting disadvantages into advantages and solving the Li|LLZTO interfacial issues.