A review of problems and solutions in Ni-rich cathode-based Li-ion batteries from two research aspects: Experimental studies and computational insights

Due to the rapidly growing energy demand and the development of electric vehicles and energy storage systems, research on high-capacity batteries is actively conducted. Among them, the Li-ion battery with a Ni-rich cathode has recently come under the spotlight due to its high capacity. However, the Ni-rich cathode suffers from problems such as electrode and interface stability, structural stability and gas emissions, among others. These issues result in poor cycling efficiency and increase the risk of battery combustion, requiring a solution. With the recent development of computational methods, they are applied to Li-ion batteries, including, but not limited to battery modeling and lithium diffusion. The calculation method has a complementary relationship with the experiments. Before conducting the experiment, the calculation method can be used to check whether the dopant and coating materials are feasible with the Ni-rich cathode, as well as the mechanism of performance improvement according to the strategy. Additionally, experimental results can be compared with calculation methods to increase the reliability of the calculations. Therefore, we summarized the current problems of Ni-rich cathodes such as phase transitions and cation mixing currently facing Ni-rich cathodes, as well as the reduction of electrochemical performance and stability problems caused by the generation of Residual Li, Cracks, and gas. Furthermore, experiments and computing methods for performance improvement using various strategies such as doping, coating, washing, and single crystalline cathodes to solve this problem were summarized. The experiments and calculation results summarized in this paper can enable accelerated discovery of Ni-rich cathode materials in the future and can provide insights into exploring the mechanisms of various phenomena.