Functional copolymer binder for nickel-rich cathode with exceptional cycling stability at high temperature through coordination interaction

Abstract

Abstract Nickel-rich layered oxide LiNi1−x−yCoxAlyO2 (NCA) with high theoretical capacity is a promising cathode material for the next-generation high-energy batteries. However, it undergoes a rapid capacity fading when operating at high temperature due to the accelerated cathode/electrolyte interfacial reactions and adhesive efficacy loss of conventional polyvinylidenefluoride (PVdF) binder. Herein, poly(acrylonitrile-co-methyl acrylate) copolymer is designed with electron-rich C N groups as a novel binder for LiNi0.8Co0.1Al0.1O2 cathode at high temperature. The electron-rich C N groups are able to coordinate with the active Ni3+ on the surface of NCA, alleviating electrolyte decomposition and cathode structure degradation. Moreover, the strong adhesive ability is conducive to maintain integrity of electrodes upon cycling at 55\xa0°C. In consequence, the NCA electrodes with this functional binder display improved cycling stability (81.5% capacity retention after 100 cycles) and rate performance at 55\xa0°C.