What are the factors that limit the charge and discharge rate performance of lithium batteries

1. The internal resistance of lithium batteries generally adds a conductive agent inside the positive active material, thereby reducing the contact resistance between the active materials, the active material and the positive electrode matrix/current collector, and improving the conductivity of the positive electrode material (ionic and electronic conductivity) , Improve the magnification performance. Conductive agents of different materials and shapes will all have an impact on the internal resistance of the lithium battery, thereby affecting its rate performance. The current collectors (tabs) of the positive and negative electrodes are the carrier for the lithium battery to transfer electric energy to the outside world, and the resistance value of the current collector also has a great influence on the rate performance of the battery. Therefore, by changing the material, size, extraction method, connection process, etc. of the current collector, the rate performance and cycle life of the lithium battery can be improved. In addition, the liquid absorption and porosity of the separator also have a greater impact on the passability of lithium ions, and will also affect the rate performance of the lithium battery to a certain extent (relatively small). The degree of infiltration between the electrolyte of the lithium battery and the positive and negative materials will affect the contact resistance at the interface between the electrolyte and the electrode, thereby affecting the rate performance of the battery. The total amount of electrolyte, viscosity, impurity content, and the pores of the positive and negative materials will change the contact impedance between the electrolyte and the electrode, which is an important research direction to improve the rate performance. 2. The ionic conductivity of the electrolyte The ionic conductivity of the electrolyte is the same as the resistance of water, and it has a very large impact on the swimming speed of lithium ions. At present, the ionic conductivity of organic electrolytes used in lithium batteries, whether liquid electrolytes or solid electrolytes, is not very high. The resistance of the electrolyte has become an important part of the overall battery resistance, and its impact on the high-rate performance of lithium batteries cannot be ignored. In addition to improving the ionic conductivity of the electrolyte, the chemical stability and thermal stability of the electrolyte should also be emphasized. When charging and discharging at a high rate, the electrochemical window of the battery has a very wide range. If the chemical stability of the electrolyte is not good, it is easy to oxidize and analyze the surface of the positive electrode material, which affects the ionic conductivity of the electrolyte. 3. Diffusion capacity of positive and negative lithium batteries The rate at which lithium batteries are deintercalated and embedded in the positive/negative active material, that is, the speed at which lithium ions escape from the positive/negative active material, or enter from the surface of the positive/negative electrode How fast can the active material find a place to settle down? This is an important factor that affects the charge and discharge rate. 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: What are the factors that affect the service life of UPS maintenance-free batteries?