An Inorganic-Rich Solid Electrolyte Interphase for Advanced Lithium-Metal Batteries in Carbonate Electrolytes

• Published in: Angewandte Chemie (International ed.) 2020-11, Vol.60 (7)
• Main Authors: Liu, Sufu, Ji, Xiao, Piao, Nan, Chen, Ji, Eidson, Nico, Xu, Jijian, Wang, Pengfei, Chen, Long, Zhang, Jiaxun, Deng, Tao, Hou, Singyuk, Jin, Ting, Wan, Hongli, Li, Jingru, Tu, Jiangping, Wang, Chunsheng
• Format: Article
• Language: English
• Subjects: carbonate electrolytes; dendrite-free structures; electrode interphases; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; lithium nitrate; lithium-metal batteries
• ISSN: 1433-7851; 1521-3773

In carbonate electrolytes, the organic-inorganic solid electrolyte interphase (SEI) formed on the lithium (Li) metal anode surface is strongly bonded to Li and experiences the same volume change as Li, thus it undergoes continuous cracking/reformation during plating/stripping cycles. Here we report, an inorganic-rich SEI is designed on a Li metal surface to reduce its bonding energy with Li metal by dissolving 4 M concentrated LiNO3 in dimethyl sulfoxide (DMSO) as an additive for a fluoroethylene carbonate (FEC) based electrolyte. Due to the aggregate structure of NO3- ions and its participation in the primary Li+ solvation sheath, abundant Li2O, Li3N, and LiNxOy grains are formed in the resulting SEI, in addition to the uniform LiF distribution from the reduction of PF6- ions. The inorganic-rich SEI’s weak bonding (high interface energy) to Li can effectively promote Li diffusion along the SEI/Li interface and prevent Li dendrite penetration into the SEI. As a result, our designed carbonate electrolyte enables a Li anode to achieve a high Li plating/stripping CE of 99.55% (1 mA cm-2, 1.0 mAh cm-2) and the electrolyte also enables a Li||LiNi0.8Co0.1Mn0.1O2(NMC811) full cell (2.5 mAh cm-2) to retain 75%of its initial capacity after 200 cycles with an outstanding CE of 99.83%.