Uncovering the limits of lithium cobalt oxide: challenges and innovations for high-voltage lithium-ion batteries

Lithium-ion batteries (LIBs) have become a crucial power source for several uses, such as portable devices, the military and space exploration, etc. The performance of LIBs is significantly influenced by the cathode materials. Lithium Cobalt Oxide (LiCoO2) is one of the most researched cathode materials used in LIBs. It was discovered by the Prof. John B. Goodenough in 1980. Due to their high specific capacities, high energy densities, and outstanding cycle life, LiCoO2 has attracted a lot of interest for use as cathode materials in LIBs. As the demand has increased for high energy density batteries due to its application in portable electronics devices, the upper cut-off voltage of LiCoO2-based batteries has been continuously increased. However, charging to high voltages (>4.2 V vs. Li/Li+) can cause several detrimental issues, such as surface degradation, inhomogeneous reactions, and damage induced by destructive phase transitions, leading to the rapid decay of efficiency, capacity, and cycle life. This chapter is focussed to an overview of the recent work done on the LiCoO2, with a significant discussion on the fundamental failure mechanisms of LiCoO2 at high voltages. Furthermore, the chapter discusses synthesis techniques for modifying LiCoO2 and the current state of LiCoO2-based LIBs. Overall, this chapter provides valuable insights into the challenges faced by LiCoO2 in high-voltage applications and highlights the need for continued research to improve its performance.