High-Voltage and Fast-Charging Lithium Cobalt Oxide Cathodes: From Key Challenges and Strategies to Future Perspectives

Lithium-ion batteries (LIBs) with the "double-high" characteristics of high energy density and high power density are in urgent demand for facilitating the development of advanced portable electronics. However, the lithium ion (Li+)-storage performance of the most commercialized lithium cobalt oxide (LCO, LiCoO2) cathodes is still far from satisfactory in terms of high-voltage and fast-charging capabilities for reaching the double-high target. Herein, we systematically summarize and discuss high-voltage and fast-charging LCO cathodes, covering in depth the key fundamental challenges, latest advancements in modification strategies, and future perspectives in this field. Comprehensive and elaborated discussions are first presented on key fundamental challenges related to structural degradation, interfacial instability, the inhomogeneity reactions, and sluggish interfacial kinetics. We provide an instructive summary of deep insights into promising modification strategies and underlying mechanisms, categorized into element doping (Li-site, cobalt-/oxygen-site, and multi-site doping) for improved Li+ diffusivity and bulk-structure stability; surface coating (dielectrics, ionic/electronic conductors, and their combination) for surface stability and conductivity; nanosizing; combinations of these strategies; and other strategies (i.e., optimization of the electrolyte, binder, tortuosity of electrodes, charging protocols, and pre-lithiation methods). Finally, forward-looking perspectives and promising directions are sketched out and insightfully elucidated, providing constructive suggestions and instructions for designing and realizing high-voltage and fast-charging LCO cathodes for next-generation double-high LIBs.