Modification of Nickel–Cobalt–Manganese Cathode Material Prepared Using Hydrothermal Method under Pulsed High Magnetic Field

High magnetic field is a unique technique for material preparation that is commonly applied in magnetic materials but seldom in electrode materials. In this study, a pulsed high-intensity magnetic field is applied in the hydrothermal synthesis of the NCM523 precursor, specifically during the formation and growth of NCM crystal particles. As a result, NCM523 had a better layered structure, alleviating the Li⁺/Ni²⁺ mixed arrangement phenomenon, and a faster Li⁺ diffusion rate. In addition, when the pulsed high magnetic field is applied, the Ni²⁺ content decreased, and the Mn⁴⁺ content increased, enhancing the electrochemical properties. In the high cutoff voltage range of 3–4.5 V and setting 1 C = 180 mA g⁻¹, the initial specific discharge capacity of NCM523 is 190.4 mAh g⁻¹, which is 12.1 mAh g⁻¹ higher than that prepared without the magnetic field. After 200 cycles, the specific discharge capacity and capacity retention rate increased by 24.4 mAh g⁻¹ and 8.5%, respectively, compared with NCM523 prepared in the absence of the magnetic field.