Modifying an ultrathin insulating layer to suppress lithium dendrite formation within garnet solid electrolytes

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2021-02, Vol.9 (6), p.3576-3583
• Main Authors: Tang, Shijun, Chen, Guiwei, Ren, Fucheng, Wang, Hongchun, Yang, Wu, Zheng, Chenxi, Gong, Zhengliang, Yang, Yong
• Format: Article
• Language: English
• Subjects: Batteries; Dendrites; Dendritic structure; Deposition; Electrolytes; Electron beams; Electron irradiation; Ions; Irradiation; Lithium; Lithium batteries; Lithium fluoride; Molten salt electrolytes; Nucleation; Plating; Radiation; Solid electrolytes; Stripping
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d0ta11311e

The electronic conductivity of solid electrolytes, which plays an important role in inducing Li dendrite deposition, is a key obstacle to the practical application of Li metal in all-solid-state lithium metal batteries. Herein, an ultrathin insulating LiF coating with controllable thickness is proposed as an electronic isolation layer to inhibit the formation of Li dendrites. The homogeneous LiF interfacial layer can effectively facilitate the physical contact of the Li metal and LLZTO electrolyte and promote uniform Li plating/stripping. In contrast to the inhomogeneous lithium nucleation and dendritic lithium growth in an unmodified LLZTO electrolyte induced by electron beam irradiation, dendritic Li deposition is efficiently inhibited on LiF coated LLZTO. The Li|0.5LF-LLZTO|Li symmetric cell exhibits a low interfacial impedance of 12.7 ohm cm 2 and stable Li plating/stripping without lithium penetration, over 1500 hours at 0.2 mA cm −2 and 300 hours at 0.4 mA cm −2 . Besides, the Li|0.5LF-LLZTO|LiCoO 2 full cell also shows excellent long-term cycling stability with a high capacity retention of 76.8% after 2500 cycles at 1C. Our results reveal the importance of tuning the interface modification layer properties to guide the uniform lithium plating toward suppressing Li dendrite formation in solid electrolytes. The ultrathin insulating LiF coating with controllable thickness is proposed as an interfacial layer for garnet electrolytes to inhibit the formation of Li dendrites, and promote uniform Li plating/stripping.