solid phase method
Generally, lithium salts such as lithium carbonate are ground and mixed with cobalt or nickel compounds, followed by a sintering reaction. The advantages of this method are its simple process flow, readily available raw materials, and its widespread research, development, and production in the early stages of lithium-ion battery development; foreign technology is relatively mature. The disadvantages are that the resulting cathode material has limited capacity, poor uniformity of raw material mixing, poor performance stability of the prepared material, and poor batch-to-batch quality consistency.
Complexation method
The complexation method involves first preparing a complex precursor containing lithium ions and cobalt or vanadium ions using organic complexes, followed by sintering. The advantages of this method are molecular-scale mixing, good material uniformity and performance stability, and higher cathode material capacity compared to the solid-state method. It has been tested as an industrial method for lithium-ion batteries abroad, but the technology is not yet mature, and there are few reports on it in China.
Sol-gel method
The method for preparing ultrafine particles, developed in the 1970s, is used to prepare cathode materials. This method combines the advantages of the complexation method and significantly improves the capacitance of the prepared electrode materials. It is a rapidly developing method both domestically and internationally. The disadvantages are high cost and the fact that the technology is still in the development stage.
Ion exchange method
The ion-exchange method for preparing LiMnO2 has yielded a reversible discharge capacity of 270 mAh/g, making this method a new research hotspot. It features stable electrode performance and high capacity. However, the process involves energy-intensive and time-consuming steps such as solution recrystallization and evaporation, which means it is still far from practical application.
