Tri-anions regulated solvation structure in intrinsically nonflammable phosphate-based electrolytes for stable lithium metal batteries
Zhiwei Ni, Chuanliang Wei, Zhengran Wang, Yuan Li, Xinlu Zhang, Shenglin Xiong, Jinkui Feng
Abstract
The cycling instability and unsafety blocked the application of lithium metal batteries (LMB). Nonflammable solvents are hoped to improve the security of LMB; however, employing these solvents will irreversibly damage the cycling stability owing to incompatibility with Li metal. Herein, we regulated solvation structures in triethyl phosphate (TEP) through a simple Tri-anions strategy to achieve cycling stability and safety of LMB. Molecular dynamic simulation demonstrates that the solvation structure is well adjusted which can induce a powerful inorganic-rich solid electrolyte interface (SEI) to circumvent parasitic reactions between TEP solvents and Li anode as well as promote uniformly Li deposition. As a result, Li/LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811) cell has a capacity retention of 98.6 % after 300 cycles and Li/LiFePO 4 (LFP) cell retains 75 % after 700 cycles. The novel electrolyte is expected to offer a promising approach for improving high safety and high-electrochemical-performance LMB.