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

Abstract

By increasing the nickle content in LiNi x Mn y Co 1-x-y O 2 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 LiNi 0.9 Co 0.05 Mn 0.05 O 2 (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. • A novel electrolyte additive BVSM to stabilize NCM90 cathode. • A robust sulfur-involved and inorganic fluorides-enriched CEI with BVSM additive. • Competitive coordination among solvents, BVSM and anions revealed by DFT. • Improved cycling stability and fast kinetics enabled by BVSM additive.