Analysis of the working principle of lithium battery and the characteristics of cathode materials

The working principle of the lithium battery The working principle of the lithium battery is relatively simple. When discharging, some lithium ions will be separated from the negative electrode material and enter the electrolyte solution, and the same amount of lithium ions will be embedded in the positive electrode material in the electrolyte. , In the external circuit, at the same time, electrons will flow from the negative pole to the positive pole to supply power to the load and supply energy. Lithium batteries can also undergo a reversible charging process, which occurs when there is current or external voltage loading on the positive and negative electrodes. The characteristics of lithium battery cathode materials After the first proposal and advent of lithium batteries, research on cathode materials has been going on. Various new cathode materials with low cost and good performance have been extensively studied and discussed as cathode materials for lithium batteries. , The several requirements that must be met are: ① easy to synthesize and low cost; ② less polluting to the environment; ③ strong stability when in contact with electrolyte; ④ strong electrical conductivity; ⑤ When lithium ions are transferred in the electrolyte, they must be able to quickly react with lithium ions during the insertion and extraction of the cathode material; ⑥ it must be able to have a reversible chemical reaction with lithium ions; ⑦ must be able to undergo redox reactions and contain transition metals element. After meeting the above requirements, the design of new cathode materials should also consider the dynamic performance and thermodynamic performance of the embedded battery system. The morphology and structure of the cathode material are also factors to be considered in the design. The diameter, density, morphology and distribution of the material particles have a great influence on the kinetics of the positive electrode of the battery, and play an important role in the stability and electrochemical performance of the battery. For example, the spherical crystal particles gather to form a single The spinel spherical crystal grains will enhance the cycle performance of the battery. The smaller particle diameter can make the chemical reaction more rapid. This is because the diffusion path of ions and electrons in the material will shorten as the particle diameter decreases, but Too small particle size also has corresponding disadvantages. For example, a lower tap density will result in too low energy density and poor thermal stability. When a reaction occurs in the electrolyte, the reaction activity will be reduced. In continuous research and analysis, various synthesis methods will synthesize material particles of different sizes, and the appropriate particle size and morphology will make the performance of the lithium battery more superior. 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: Technical difficulties and processing technology analysis of lithium battery diaphragm