Regulating the Electrode-Electrolyte Interfaces of Lithium-High Nickel Batteries via a Multifunctional Additive

Lithium metal batteries with high nickel ternary (LiNiCoMn_1-O₂, x ≥ 0.8) as the cathode hold the promise to meet the demand of next-generation high energy density batteries. However, the unsatisfactory stability of electrode-electrolyte interfaces limits their practical applications. In this work, N-methyl-N-trimethylsilyltrifluoroacetamide (NMTFA) is suggested as a new functional electrolyte additive to stabilize the Li∥LiNi_0.9Co_0.05Mn_0.05O₂ chemistry by forming robust and effective electrode-electrolyte interphases, namely the anode-electrolyte interphase (AEI, or conventionally called SEI) and cathode-electrolyte interphase (CEI). The NMTFA-derived SEI/CEI greatly enhances the battery performance that a capacity retention of 82.1% after 200 cycles at 1C charge/discharge is achieved, significantly higher than that without NMTFA addition (52.5%). Moreover, the NMTFA also improves the thermal stability of the electrolyte and inhibits the hydrolysis of LiPF₆. This work provides new clues for the optimization of electrolyte formulation for lithium-high nickel batteries through modulating interfaces.