The preparation technology of nickel-based cathode materials mainly includes the following methods:
Co-precipitation method: This is one of the most commonly used methods for synthesizing high-nickel ternary cathode materials. By controlling factors such as reaction time and complexing agent concentration, the morphology and electrochemical performance of the material can be optimized. For example, when the reaction time is 8 hours, the high-nickel ternary cathode material produced has the best overall specific capacity and cycling performance.
Hydrothermal method: This method is carried out under high temperature and pressure, suitable for synthesizing materials with specific morphology and structure. The hydrothermal method can control the properties of the product by adjusting parameters such as reaction temperature, time, and solvent.
Solvothermal method: Similar to the hydrothermal method, but uses organic solvents as the reaction medium. This method can synthesize materials with good crystallinity and uniform particle size.
Sol-gel method: This involves converting a metal salt solution into a sol, followed by drying and calcination to obtain the final product. This method allows for precise control of the composition and structure of the material.
Spray pyrolysis method: The metal salt solution is spray-dried and then pyrolyzed. This method is suitable for large-scale production and can obtain materials with uniform particle size.
Template method: This method uses templates to control the morphology and structure of the material. It can synthesize materials with specific shapes and porosity.
The process flow for high-nickel ternary cathode materials includes the following steps:
Lithiation mixing: The precursor is mixed with a lithium source, usually using dry mixing. High-nickel materials require more uniform mixing and stricter control of humidity.
Loading: To prevent spontaneous agglomeration of the material during the sintering process, the loading amount must be strictly controlled.
Calcination: Calcination is the core process for high-nickel ternary materials, usually requiring pre-calcination and multiple sintering, with temperatures between 750 and 800°C, and a long duration (20 to 25 hours).
Crushing and classification: The particles after calcination need to be crushed to the micron level, usually undergoing three stages of crushing and screening.
Impurity removal and packaging: After removing impurities, the cathode material is vacuum packaged to form the finished product.