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

Abstract

The P(AN-MA) binder can alleviate electrolyte decomposition and inhibit NCA cathode structure degradation at high temperature through the coordination interaction between electron-rich C N groups and active Ni 3+ on the surface of NCA. • The NCA cathode exhibits improved cycling performances at 55 °C with P(AN-MA). Nickel-rich layered oxide LiNi 1 − x − y Co x Al y O 2 (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 LiNi 0.8 Co 0.1 Al 0.1 O 2 cathode at high temperature. The electron-rich C N groups are able to coordinate with the active Ni 3+ 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 °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 °C.