Shi Kai, Wan Zipei, Yang Lu, Zhang Yiwen, Huang Yanfei, Su Shiming, Xia Heyi, Jiang Keling, Shen Lu, Hu Yi, Zhang Shiqi, Yu Jing, Ren Fuzeng, He Yan-Bing, Kang Feiyu
Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China.
Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
Angew Chem Int Ed Engl. 2020 Jul 13;59(29):11784-11788. doi: 10.1002/anie.202000547. Epub 2020 May 18.
The garnet electrolyte presents poor wettability with Li metal, resulting in an extremely large interfacial impedance and drastic growth of Li dendrites. Herein, a novel ultra-stable conductive composite interface (CCI) consisting of Li Sn alloy and Li N is constructed in situ between Li La Zr Ta O (LLZTO) pellet and Li metal by a conversion reaction of SnN with Li metal at 300 °C. The Li Sn alloy as a continuous and robust bridge between LLZTO and Li metal can effectively reduce the LLZTO/Li interfacial resistance from 4468.0 Ω to 164.8 Ω. Meanwhile, the Li N as a fast Li-ion channel can efficiently transfer Li ions and give their uniform distribution at the LLZTO/Li interface. Therefore, the Li/LLZTO@CCI/Li symmetric battery stably cycles for 1200 h without short circuit, and the all-solid-state high-voltage Li/LLZTO@CCI/LiNi Co Mn O battery achieves a specific capacity of 161.4 mAh g at 0.25 C with a capacity retention rate of 92.6 % and coulombic efficiency of 100.0 % after 200 cycles at 25 °C.
石榴石电解质与锂金属的润湿性较差，导致界面阻抗极大且锂枝晶急剧生长。在此，通过在300 °C下SnN与锂金属的转化反应，在LiLaZrTaO（LLZTO）颗粒和锂金属之间原位构建了一种由锂锡合金和氮化锂组成的新型超稳定导电复合界面（CCI）。锂锡合金作为LLZTO和锂金属之间连续且坚固的桥梁，可有效将LLZTO/锂界面电阻从4468.0 Ω降低至164.8 Ω。同时，氮化锂作为快速锂离子通道，能够高效传输锂离子并使其在LLZTO/锂界面均匀分布。因此，Li/LLZTO@CCI/Li对称电池可稳定循环1200 h而不短路，并且全固态高压Li/LLZTO@CCI/LiNiCoMnO电池在25 °C下以0.25 C循环200次后，比容量达到161.4 mAh g，容量保持率为92.6 %，库仑效率为100.0 %。
