Critical review on the degradation mechanisms and recent progress of Ni-rich layered oxide cathodes for lithium-ion batteries

Ni-rich layered transition metal oxides possess remarkably high capacity and thus are very competitive cathode materials in high-energy lithium-ion batteries (LIBs) for electric vehicles, but encounter the critical problems of fast degradation caused by the highly reactive nickel component. Here in this review we intensively summarize thedegradation mechanism of Ni-rich cathode materials including e.g., residual lithium species, cation mixing, gas generation, surface structure reconstruction, crack, thermal instability, and transition metal dissolution. Furthermore, the state-of-art strategies e.g., new preparation methods, single-crystal, doping, structure design, coating and new binders, to tackle these degradation problem are accounted. This review might be inspiring for better understanding the degradation mechanism and relevant coping approaches of high-energy cathode materials for lithium ion batteries.