Cooperative stabilization of bi-electrodes with robust interphases for high-voltage lithium-metal batteries

• DOI: 10.1016/j.ensm.2021.02.039
• Publication Date: 2021-02-24T07:43:01Z
• Authors: Qianqian Liu; Zerui Chen; Yan Liu; Youran Hong; Weina Wang; Jianghao Wang; Bo Zhao; Yifei Xu; Jiangwei Wang; Xiulin Fan; Linsen Li; Hao Bin Wu
• Keywords: 01 natural sciences; 7. Clean energy; 0104 chemical sciences; 3. Good health

Abstract Stable electrode-electrolyte interphases on both electrodes are indispensable to warrant cycling stability of high-voltage Li-metal batteries. Here, we reveal a unique cooperative reaction mechanism to form protective interphase layers on both Li-metal anode and high-voltage cathodes, which is exemplified by a multifunctional additive ethoxy(pentafluoro)cyclotriphosphazene (PFPN). The F-rich PFPN first reacts with Li-metal anode to form LiF-rich solid electrolyte interphase (SEI), which stabilizes the Li deposition/dissolution processes. Meanwhile, the in-situ generated PFPN derivatives with a de-fluorated structure are prone to be oxidized on cathode, forming a robust cathode-electrolyte interphase (CEI) to prevent electrolyte oxidation and electrode degradation at high voltage. With PFPN to harness the aggressive battery electrodes, Li-metal batteries with high-voltage LiCoO2 (4.5 V) and LiNi0.5Mn1.5O2 (4.9 V) cathodes exhibit improved cycling stability and rate capability. In particular, the LiNi0.5Mn1.5O2|Li full cell with limited Li supply (N/P =7.6) demonstrates outperformed capacity retention of 90.7 % after 100 cycles, which is almost twice that of the cell using PFPN-free conventional electrolyte (47.5 %).