Basic Scientific Problems of Nickel-Rich Cathode for Lithium-Ion Battery: Destabilization Mechanism and Modification Strategies

Nickel-rich layered cathodes with high discharge capacity and high voltage platform are recognized as positive materials used for long-life power batteries. However, due to the fragile lattice and poor thermal property, Ni-rich cathode materials have poor stability during repeated lithiation/delithiation, which makes it difficult for batteries to serve for a long period. In this paper, the mechanism of degradation of stability caused by residual lithium, cationic mixing, gas release, irreversible phase change and micro-cracks for nickel-rich cathode materials is analyzed. The modification strategies adopted in recent years to solve the above problems are summarized, such as element doping, surface coating, single crystallization, concentration gradient structure design and introduction of electrolyte additives. Moreover, the future direction and application prospect of those modification strategy are also discussed.