Surface/Interface Structure Degradation of Ni‐Rich Layered Oxide Cathodes toward Lithium‐Ion Batteries: Fundamental Mechanisms and Remedying Strategies

Nickel‐rich layered transition‐metal oxides with high‐capacity and high‐power capabilities are established as the principal cathode candidates for next‐generation lithium‐ion batteries. However, several intractable issues such as the poor thermal stability and rapid capacity fade as well as the air‐sensitivity particularly for the Ni content over 80% have seriously restricted their broadly practical applications. The properties and nature of the stable surface/interface, where the Li+ shuttles back and forth between the cathode and electrolyte, play a significant role in their ultimate lithium‐storage performance and industrial processability. Thus, tremendous efforts are made to in‐depth understanding of the essential origins of surface/interface structure degradation and efficient surface modification methodologies are intensively explored. The purpose of the contribution is first to provide a comprehensive review of the up‐to‐date mechanisms proposed to rationally elucidate the surface/interface behaviors, and then, focus on recent developed strategies to optimize the surface/interface structure and chemistry including synthetic condition regulation, surface doping, surface coating, dual doping‐coating modification, and concentration‐gradient structure as well as electrolyte additives. Finally, the perspective on future research trends and feasible approaches toward advanced Ni‐rich cathodes with stable surface/interface is presented briefly. Surface/interface structure and chemistry of the nickel‐rich cathodes are essential for electrochemical properties and industrial processability of advanced Li‐ion batteries. The purpose of the contribution is to provide a comprehensive review of the up‐to‐date mechanisms proposed to rationally elucidate the surface/interface behaviors, and then, focuses on recent developed strategies to optimize the surface/interface toward next‐generation Li‐ion batteries.