Interfacial Regulation and Hydrogen Fluoride Capture Enabled by Allyltrimethylsilane as Multifunctional Electrolyte Additive for Li/LiNi_0.8Co_0.1Mn_0.1O₂ Batteries

Lithium metal batteries (LMBs) coupled with Ni-rich cathodes are promising next-generation solutions for high-energy-density energy storage devices. Nevertheless, many challenges concerning structural evolution of electrode materials as well as electrolyte decomposition, which mainly stem from a defect of the electrode–electrolyte interface (EEI) toward aggressive chemistries: Li metal anode (LMA), high nickel cathode materials, and LiPF6-based carbonate electrolytes, need to be addressed. In this work, the EEI layers on the LMA and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode are tailored, and the hydrogen fluoride (HF) attack is eliminated by applying a multifunctional electrolyte additive allyltrimethylsilane (ATMS). Theoretical calculations and physicochemical characterizations reveal that the C═C and Si–C groups of ATMS can fulfill the bielectrode–electrolyte interphase regulation and HF capture, respectively. Consequently, by being incorporated with the ATMS additive, the Li/NCM811 battery delivers remarkably enhanced capacity retention of 82.9% with regard to the reference cell with the baseline electrolyte (46.4%) after 200 cycles, and the Li/Li cell exhibits a prolonged lifespan beyond 1000 h at 0.5 mA cm–2.