Effect of cation mixing of Li+/Ni2+ on heat generation of NCM811 cathode during long-term cycling at elevated temperature

The heat generation power of an electrode is one of the key factors affecting the operation safety and even the electrochemical performances of lithium-ion batteries. Herein, the heat generation power of a LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode at different cycling stages at an elevated temperature (50 °C) is studied. The internal and external factors, such as Li+ diffusion coefficient and Li+/Ni2+ cation mixing, affecting probably the heat generation are elaborated experimentally and theoretically. It is illustrated that the cation mixing of Li+/Ni2+ occurred during charge/discharge cycling reduces severely the diffusion coefficient of Li+ in NCM811 that accounts further for the increase in the as-generated heat amount and the heat generation power of the NCM811 with the cycling process.