Document Type : Original Reaearch Article

Authors

1 Materials and Energy Research Center

2 material and energy research center

3 Material and Energy Research Center

4 Materials and Energy Research center

10.30501/jamt.2022.351905.1238

Abstract

Nickel-rich layered oxide cathode materials LiNi0.8Co0.1Mn0.1O2 (NCM) are increasingly being considered in the electric vehicle industry due to their high energy density and high capacity. Although, increasing the nickel concentration, the chemical reaction of the surface layer and the Li+/Ni2+ cationic mixing increase and the structural and thermal stability of the cathode material decreases. The strategy of single crystallization of particles can improve the structural stability and electrochemical performance of cathode materials, but its mechanism is not fully understood. In this research, we present a computational model to show that by reducing the pH and controlling the amount of supersaturation, the nucleation rate of hydroxide particles decreases and as a result, the number of formed nucleas decreases. Based on the results of this model, the number of hydroxide nucleas formed at the end of co-precipitation synthesis at pH 11.5, 11 and 10.5 is 5.73, 4.3 and 2.27 times, respectively, the number of nucleas formed in co-precipitation synthesis at pH 10. Therefore, by reducing the pH value during the synthesis process from 11.5 to 10, the fine particles produced in the system are allowed to completely transform into larger crystals and tend to become single crystals, and the problems of the cathode/electrolyte intermediate layer are reduced in them. The results of this model can justify the experimental results of researches that have synthesized single crystal cathode materials.

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