Experimental Study on the Chemical Reaction Characteristics in the Calcination Process of an 811 Ternary Cathode Material

The research on 811 ternary cathode materials is mainly based on synthesis and modification. However, the preparation process of these materials is accompanied by complex chemical reactions, and the reaction process and corresponding kinetic analysis have not been widely explored. Under different oxygen concentrations, this study analyzed the chemical reaction mechanism of the raw material's (namely, Ni_0.8Co_{0. 1}Mn_{0. 1}(OH)₂ and LiOH·H₂O mixture, which is referred to as the raw material hereinafter) calcination process by non-isothermal thermogravimetry, differential scanning calorimetry, and in situ X-ray diffraction. Based on the obtained data, multiple heating rate methods were used to calculate the reaction mechanism functions and kinetic parameters at each stage as well as the corresponding activation energy and pre-exponential factor. Results showed that four chemical reactions occurred successively during the calcination process of the raw materials with each corresponding to a different kinetic function, pre-exponential factor, and activation energy. Comparing the calcination characteristics under different oxygen concentrations showed that the activation energy was the smallest when the oxygen concentration was 60%.