The application of LiCoO2 in the cathode materials of lithium ion batteries has great advantages, mainly reflected in the reversible insertion and separation of lithium ions, as well as the large lithium ion diffusion coefficient, reversible insertion amount and structure change degree. Therefore, LiCoO2 plays an important role in improving the charging and discharging current of lithium batteries. At the same time, the material has stable structure, good lithium ion deinterlacing reversibility, and can effectively ensure the coulomb efficiency of charge and discharge and the service life of the battery. Through the research on the capacity attenuation mechanism of LiCoO2 system by relevant scholars at home and abroad, it is found that the factors affecting the capacity attenuation change during the lithium battery cycle are mainly due to the increase of anode interface impedance and the loss of cathode capacity.

At the same time, relevant scholars also found that the higher the number of cycles, the lower the contribution of the capacity loss of the positive and negative electrodes compared with the total battery capacity loss, and the decline of the mobility of active lithium ions will have a greater impact on the overall capacity decline of the battery. It can be seen from Figure 1 that after the number of battery cycles is more than 200, the positive material does not undergo phase change, while the regularity of LiCoO2 layer structure decreases, and the mixed arrangement of lithium ions and chromium ions increases, making it difficult for lithium ions to be effectively de embedded, which leads to the decline of battery capacity. In addition, increasing the discharge rate will promote the mixing of lithium and chromium atoms, which will lead to the transformation of the original hexagonal crystal form of LiCoO2 into cubic crystal form, thus causing the capacity degradation of lithium ion batteries.

In addition, in the LiCoO2 system, through the study of the attenuation law of the battery cycle capacity at 25 ℃ (i.e. at room temperature) and 60 ℃, it can be found that before 150 cycles, the discharge capacity of the battery below 60 ℃ is higher than the battery capacity and rated capacity at room temperature. This is because the electrolyte viscosity decreases at high temperature, which increases the lithium ion migration rate, thereby improving the utilization rate of active lithium. The battery shows a high charge discharge capacity. After 300 cycles, the polarization capacity loss of the battery at 60 ℃ is much higher than that at room temperature. It can be seen that the increase in temperature intensifies the electrochemical polarization of the electrode during the charging and discharging process of the lithium ion battery, making the capacity loss of the lithium battery more serious during the charging and discharging process.