Study on the preparation of LiCoO2 by multiphase redox method

• A new method to prepare LiCoO2 named multiphase redox method is introduced.
• The best conditions for synthesis of the precursors have been obtained.
• Sintered products present good electrochemical performance.
• The initial discharge capacity is above 150 mAh g− 1.
• The average decay rate of each cycle is only 0.04% in the initial eight cycles.

We report a new method, which is called multiphase redox method, to prepare LiCoO2 cathode material. The SEM results of precursors show that the secondary particles are dispersed well. The effects of process conditions on the preparation of precursors for LiCoO2 have been studied and the best conditions for synthesis of the precursors have been obtained. The reaction temperature is 75–85 °C; the reaction time is 6–8 h and the Li+ concentration is 20–30 g L− 1. Under these conditions, the precursors have been obtained, in which specific surface area (BET) is 20–50 m2 g− 1; the particle size is about 100 nm and n(Li)/n(Co) is 0.8 to 1.0. The best sintering process is as follows. The heating rate is 165 °C h− 1; the sintering temperature is 850 °C and the retention time is 5 h. Sintered products present good electrochemical performance. The results indicate that the initial discharge capacity is above 150 mAh g− 1 and the average decay rate of each cycle is only 0.04% in the initial eight cycles.

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