Enhancing Surface and Crystal Stability of the Ni-High NCA Cathode for High-Energy and Durable Lithium-Ion Batteries

Abstract

The promising LiNi0.92Co0.05Al0.03O2 (NCA) cathode materials have become attractive recently for high-energy-density lithium-ion batteries (LIBs), but they suffer from severe capacity fade due to structure degradation and interface instability. Herein, a dual-modification strategy of Nb doping and Li4SiO4 coating is employed to consolidate the surface and crystal stability of NCA. The Nb doping could suppress the anisotropic volume change and alleviate the generation of microcracks. Also, the Li4SiO4 coating layer effectively accelerates the Li-ion transfer and protects the NCA surface from electrolyte attack. These advantages make the dual-modified NCA exhibit a high specific capacity of 199.2 mA h g–1 at 1 C with a capacity retention of 93.3% after 100 cycles. It delivers a high capacity of 160.0 mA h g–1 at 10 C, much higher than the pristine NCA (138.2 mA h g–1). The structure–performance relationship has been discussed. This work may provide guidance to modify Ni-high cathode materials for enhancing the high-energy and cyclic performance of LIBs.