3 lithium negative modificationPeled in 1979, the concept of SEI film was first proposed. The multi-phase chemical structure of the SEI membrane had a direct impact on electroplating, peeling behavior and cycle life of metal lithium batteries. It is an important aspect of solving the challenge of metal lithium secondary battery.
According to the current research, the modified idea of the Lithium negative electrode by modifying the SEI film is mainly: (1) The main component of the SEI film is made of decomposing reaction product of negative electrode lithium and electrolyte, and modified the SEI film by improving the electrolyte. Yes * Direct and efficient method; (2) artificial non-in-situ forms a layer of SEI film in lithium negative surface, more flexible, and the plan is more simple and economical.
3.1 Modified SEI film by electrolyte in situ
Typically, the lithium battery electrolyte is mainly composed of an organic solvent, a lithium salt, and an additive, and almost all of the electrolyte components have an important effect on the formation of the SEI film, and the stable SEI film is formed directly by improving the component of the electrolyte. Direct efficiency.
3.1.1 Liquid electrolyte
Usually used carbonate electrolytes do not inhibit the growth of lithium dendrites, and the couluminous efficiency of the battery is also low. Usually used ether electrolytes have better inhibitory effects of lithium derinating crystals, but their ionically conductivity is poor, and there is a poor antioxidant capacity, which seriously limits its application in high voltage positive electrodes. Therefore, exploring the new electrolyte system and looking for new organic solvents and lithium salts is the main task in the research work of electrolyte.
The researchers found that "high concentration lithium salt" pair forms a stable SEI film, thereby improving the lithium negative electrode has a significant effect. Hu et al. Proposed "solvent dissolved in lithium salt" research ideas, organic solvents are 1,3-dioxolane (Dol) + ethylene glycol dimethyl ether (DME) (volume ratio 1: 1), add high concentration lithium When salt litfsi, the surface of the lithium negative electrode formed a stable SEI film, and the solution had a high lithium ion migration (0.73), which effectively inhibited the growth and shape of lithium dendrites, and coulomb efficiency reached 100%.
Wuxi Huizhong, Nanjing Xia Hua, Wuxi Recommend: LiFePO4 Battery Manufacturer Energy storage battery Manufacturer Integrated machine energy storage battery series Manufacturer Lead lithium battery Manufacturer Outdoor Backup Battery Manufacturer Portable outdoor power supply Manufacturer Power battery Manufacturer Powerwall LiFePO4 Battery Manufacturer Battery rack Manufacturers Telecom LiFePO4 Battery Manufacturer Wall mounted battery storage Manufacturer China Lifepo4 Battery
