What are the reasons for the aging and decline of lithium-ion battery materials

The process of charging and discharging cycles of lithium-ion battery packs is the process of deintercalation and movement of lithium ions back and forth between the positive and negative materials through the electrolyte. In the cycle of lithium-ion battery packs, in addition to redox reverberation at the positive and negative electrodes, there are also a large number of secondary reverberations. If the secondary reverberation of lithium-ion batteries can be reduced to a low level, so that lithium ions can always smoothly go back and forth between the positive and negative materials through the electrolyte, the cycle life of lithium-ion batteries can be increased. The nature of the positive and negative current collectors will also affect the battery capacity and cycle life. The commonly used current collector materials for the positive and negative electrodes of lithium-ion battery packs are aluminum and copper, both of which are perishable metal materials. After the current collector is corroded, a passivation film is formed, poor adhesion, partial corrosion (pitting) and overall corrosion increase the internal resistance of the battery, resulting in capacity loss and low discharge efficiency. The adhesion and corrosion resistance can be strengthened by pretreatment methods such as acid-alkali etching and conductive coating. The utilization process of lithium-ion battery packs is the process of charging and discharging cycles. The size of the charge and discharge current, the selection of charge and discharge cut-off voltage, and the charging and discharging method for recycling, etc., have a very important impact on the cycle life of lithium-ion batteries. . Where blindly increase the working current of the battery, increase the charging cut-off voltage, lower the discharge cut-off voltage and other cities, the performance of the lithium-ion battery pack decreases. The difference in the charge-discharge cut-off voltage of lithium-ion batteries in different electrochemical systems. In the process of lithium-ion battery charging, if the charging cut-off voltage is higher, it is considered that overcharge has occurred. When a lithium-ion battery is overcharged, the excess lithium ions extracted from the positive electrode will be deposited or embedded on the negative electrode, and the deposited active lithium easily reacts with the solvent, releasing heat to increase the battery temperature. When the discharge voltage of the lithium-ion battery is lower than the discharge cut-off voltage, overdischarge is formed. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.