From Contaminated to Highly Lithiated Interfaces: A Versatile Modification Strategy for Garnet Solid Electrolytes
Xuerui Yang, Shijun Tang, Chenxi Zheng, Fucheng Ren, Yaxin Huang, Xinjie Fei, Yang Wu, Siyu Pan, Zhengliang Gong, Yong Yang
Abstract
Abstract The surface chemistry of garnet electrolyte is sensitive to air exposure. The poor LLZO/Li interface caused by Li 2 CO 3 /LiOH contaminants on garnet electrolyte surface easily induces large interfacial resistance resulting in the growth of Li dendrites. Herein, a versatile modification strategy is designed to convert the contaminants on Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) surface into a LiF and Li 2 PO 3 F‐rich lithiophilic interface by targeted chemical reactions at the interface between LiPO 2 F 2 and Li 2 CO 3 /LiOH. The newly formed LiF‐Li 2 PO 3 F interfacial layer not only facilitates the interface wettability between Li and LLZTO, but also helps to resist corrosion of the LLZTO surface by moisture in the air. The Li|LiF&Li 2 PO 3 F‐LLZTO|Li symmetric cell exhibits a low interfacial resistance of 5.1 Ω cm 2 and ultrastable galvanostatic cycling, over 1500 h at 0.6 mA cm −2 and over 70 h at 1.0 mA cm −2 . In addition, LiCoO 2 |LiF&Li 2 PO 3 F‐LLZTO|Li hybrid solid‐state full cells display high initial specific capacity of 192 mAh g −1 at 0.1 C, and excellent cycling stability with a capacity retention over 76% even after 1000 cycles at 0.5 C at a high cut‐off voltage of 4.5 V. This study provides a simple and practical strategy for the feasibility of the application of high‐voltage cathodes in this modified garnet all‐solid‐state batteries.