Challenges and prospects of nickel-rich layered oxide cathode material

The increasing electromobility demands rechargeable batteries with high energy density and enhanced electrochemical properties. However, the commercialized lithium-ion batteries experience several critical challenges related to cost-effectiveness, long-term safety and calendar life. Ni-rich layered oxides, LiNixCoyMnzO2 (NCM) and LiNixCoyAlzO2 (NCA) (x + y + z = 1, x ≥ 0.8) have been considered as next-generation cathode materials with the capability to achieve high energy density (800 Wh kg−1) and high operating voltage with low cost. However, their intrinsic unstable behavior, including surficial/interfacial issues, fatigue, inter/intragranular cracking, parasitic side reactions and thermal runway, causes severe capacity and voltage fading, deprived rate capability, and safety concerns during the charge/discharge process. This review article focuses on degradation mechanisms, challenges, and the most recent approaches, including doping, surface coating, structural engineering, dual modification, concentration gradient, and single-crystal cathodes were precisely summarized. Besides, the new series of Ni-based cathodes were discussed to alter the primary microstructural particle by replacing Co/Mn/Al in NCM and NCA. Notably, the compatibility and interfacial challenges of Ni-rich cathodes with solid-state electrolytes were elaborated to stabilize the electrochemical performance of this high-voltage cathode in all-solid-state batteries (ASSBs). The outlook presents a perception towards the practical application of Ni-rich layered oxide cathode materials in electromobility.