The correlation between structure and thermal properties of nickel-rich ternary cathode materials: a review

Ni-rich ternary cathode materials for Li-ion batteries have the advantages of high reversible capacity, high energy density, improved rate performance and low cost. However, they suffer from problems such as fast capacity decay, poor cycle performance and thermal instability. In this study, we review the structure of Ni-rich ternary cathode materials and analyse their structural defects. Then, we summarise the strategies for improving thermoelectric performance, such as element doping and surface coating, as well as the mechanism of change in the material structure after modification for improving thermal stability. We conclude that the prerequisite for improving the thermal stability of Ni-rich ternary materials is the structural stability, which improves the safety of Li ion batteries. Because experimental analysis is relatively not enough, it is difficult to reflect the process of thermal changes within the battery in real time. Therefore, for Li-ion battery systems, thermo-electrochemical analysis is employed to obtain relevant thermodynamic and electrochemical parameters. The exothermic law is obtained, and the corresponding solutions are proposed to solve the thermal safety problem of batteries with Ni-rich ternary cathodes.