A novel cathode interphase formation methodology by preferential adsorption of a borate-based electrolyte additive

Abstract

Abstract The coupling of high-capacity cathodes and lithium metal anodes promises the next generation of high-energy-density batteries. However, the fast-structural degradations of the cathode and anode challenge their practical applications. Herein, we synthesize an electrolyte additive, tris(2,2,3,3,3-pentafluoropropyl) borane (TPFPB), for ultra-stable lithium (Li) metal||Ni-rich layered oxide batteries. It can be preferentially adsorbed on cathode surface to form a stable (B and F)-rich cathode electrolyte interface film, which greatly suppresses the electrolyte-cathode side reactions and improves the stability of cathode. In addition, the electrophilicity of B atoms in TPFPB enhances 30 times of the solubility of LiNO3 in ester electrolyte to significantly improve the stability of Li metal anode. Thus, the Li||Ni-rich layered oxides full batteries using TPFPB show high stability and ultralong cycle life (up to 1500 cycles), which also present excellent performance even under high voltage (4.8 V), high areal mass loading (30 mg cm−2) and wide temperature range (−30∼60°C). The Li||LiNi0.9Co0.05Mn0.05O2 (NCM90) pouch cell using TPFPB with a capacity of 3.1 Ah reaches a high energy density of 420 Wh kg−1 at 0.1 C and presents outstanding cycling performance.