Tuning interface stability of nickel-rich LiNi0.9Co0.05Mn0.05O2 cathode via a novel bis(vinylsulphonyl)methane additive

By increasing the nickle content in LiNixMnyCo1-x-yO2 cathodes, the energy density and cost of lithium ion batteries (LIBs) could be further optimized. However, the structural/interfacial instability of nickel-rich cathode extremely challenges its cycling life. Here, we demonstrate a novel electrolyte additive bis(vinylsulphonyl)methane (BVSM) to enhance the cycling stability and rate capability of LiNi0.9Co0.05Mn0.05O2 (NCM90) cathode. Detailed surface characterizations prove the construction of a robust sulfur-incorporated and inorganic fluorides-enriched cathode-electrolyte interphase (CEI) film on the NCM90 surface. This BVSM-derived CEI contributes to a more reliable NCM90 cathode with suppressed interfacial side reactions, limited growth of interfacial resistance, fast electrode kinetics, less transition metal (TM) dissolution and more reversible phase transition. More importantly, first-principles calculations unravel the competitive coordination among solvents, BVSM and anions, rationalizing the CEI composition and electrochemical performance. Furthermore, the better cycling stability and stabilized average discharge voltage for graphite||NCM90 full cells are enabled by BVSM additive.