What are the effects of lithium battery SEI film on battery performance?

The use of SEI should be decomposed from its own characteristics. Its characteristics are: ① SEI is an interface layer between the electrode material and the electrolyte, which separates the two. ②It has the characteristics of a solid electrolyte; ③Li+ can pass smoothly, but electrons cannot pass. 1. The degree of corrosion caused by the reaction between metallic lithium and electrolyte components is determined by the passivation performance of the SEI film on its surface. 2. The dissolution-deposition process of lithium must occur through the SEI film, and the migration of lithium ions through the SEI film is the rate control step of the lithium deposition-dissolution process, which determines the average of the lithium deposition-dissolution process. When the deposition of lithium is average, during the cycle, the metal lithium can be mostly guarded against corrosion, so that the lithium electrode can obtain better cycle efficiency. 3. Lithium ions can undergo lithium deposition and dissolution through the SEI film, but during the dissolution and deposition process, the SEI film composed of ion components is difficult to adapt to the changes in the lithium surface morphology during the above process, so the SEI film is broken , Leading to the emergence of bare lithium and the further reaction of its electrolyte. Therefore, in the repeated deposition-solvothermal process of lithium, lithium and electrolyte components are continuously consumed, resulting in degradation of the cycle performance of the lithium electrode. 4. The fragmentation of the SEI film will lead to the formation of some high active sites, thereby accelerating the deposition of lithium in these sites and the speed of the solvent, resulting in uneven current distribution on the surface of the lithium electrode, unevenness and the formation of dendrites lead to a series of safety problems This is the main reason why the commercial use of lithium metal batteries has failed. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Brief description of the development trend of lithium battery electrolyte