A Multilayer Ceramic Electrolyte for All‐Solid‐State Li Batteries
Jianxun Zhu, Xiaolei Li, Changwei Wu, Jian Gao, Henghui Xu, Yutao Li, Xiangxin Guo, Hong Li, Weidong Zhou
Abstract
Abstract Despite of the good stability with Li‐metal, Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) suffers from large interfacial resistance and severe Li‐metal penetration. Herein, a dual layer ceramic electrolyte of Ti‐doped LLZTO(Ti‐LLZTO)/LLZTO was developed, with the reducible Ti‐LLZTO layer contacting Li‐metal and the LLZTO layer contacting cathode. The identical crystal structures of Ti‐LLZTO and LLZTO enables a seamless contact and a barrierless Li + transport between them. The densities of Ti‐LLZTO pellets are higher than that of LLZTO. With an in situ reduction of Ti‐LLZTO by Li‐metal, the interfacial wettability was improved and a mixed ion‐electron conducting layer was created. Both features help to reduce defects/pores on interface and homogenize the interfacial ionic/electronic flux, facilitating the reduction of interfacial resistance and suppression of dendrites. With the help of Ti‐LLZTO layer, long‐term stable lithium plating/stripping was reached in an areal capacity of 3.0 mAh cm −2 .