The properties of electrolyte, including electrolyte, solvent and additive, will affect the service life, specific capacity, rate charge discharge performance and safety performance of the battery. The decomposition of electrolyte and solvent in electrolyte will cause the loss of battery capacity. During the first charge and discharge, the formation of SEI film on the cathode surface by solvent and other substances will cause irreversible capacity loss, but this is inevitable. If there are impurities such as water or hydrogen fluoride in the electrolyte, the electrolyte LiPF6 may decompose at a high temperature, and the products generated will react with the cathode material, which will affect the battery capacity. At the same time, some of the products will react with the solvent and affect the stability of the SEI film on the anode surface, which will cause the performance degradation of the lithium ion battery. In addition, if the products of electrolyte decomposition are not compatible with the electrolyte, the positive electrode pores will be blocked during migration, which will lead to battery capacity degradation. In general, the occurrence of side reactions between the electrolyte and the positive and negative poles of the battery, as well as the by-products, are the main factors causing the battery capacity degradation.

In general, lithium ion batteries will suffer from capacity loss. This process is called self discharge, which is divided into reversible capacity loss and irreversible capacity loss. The oxidation rate of the solvent has a direct impact on the self discharge rate. The positive and negative active materials may react with the solute during the charging process, leading to the capacity imbalance and irreversible decay of lithium ion migration completion. Therefore, it can be seen that reducing the surface area of the active material can reduce the capacity loss stall rate, and the decomposition of the solvent will affect the battery storage life. In addition, leakage of the diaphragm will also lead to capacity loss, but this possibility is low. If the self discharge phenomenon exists for a long time, it will lead to the deposition of lithium metal, and further lead to the attenuation change of the positive and negative electrode capacities.