Multipoint adsorption constructs stable interface chemistry for high-nickel cathode material

Abstract

LiNi0.83Co0.12Mn0.05O2 (NCM), a common commercial material, has been applied widely in electric mobility and large-scale energy storage fields with its high energy density and voltage platform. Nonetheless, the battery life of long-term operation is significantly harmed by the unstable crystal structure and cathode-electrolyte interface. Among these, capacity decay is closely associated with the dissolution of transition-metal ions. In the present work, a surface-modified strategy is proposed, that is, ethyl α-cyanoacrylate (ECA) is adsorbed to the transition metal site by polar functional group and then initiates its polymerization to obtain poly(ethyl α-cyanoacrylate) (PECA) coating. The functional coating can lessen the degradation of interface by-products and construct a thinner CEI film for lithium-ion fast conduction. Furthermore, the conformal and complete coating alleviates the structural degradation after the long-term cycle. The above benefits explain the improved performance of PECA modified material and perform well even at high-temperature and high-voltage tests, thus reflecting that the modification strategy provides practical guidance for improving the performance of lithium-ion power batteries.