What is the low temperature characteristics of lithium battery cathode materials?

Low-temperature characteristics of lithium battery cathode materials 1. The low-temperature characteristics of layered structure cathode materials The layered structure not only has a multiplier function that cannot be compared with one-dimensional lithium ion dispersion channels, but also has the structural stability of three-dimensional channels. It is the earliest commercial lithium Battery positive data. Its representative materials are LiCoO2, Li(Co1-xNix)O2 and Li(Ni,Co,Mn)O2 and so on. Xie Xiaohua and others took LiCoO2/MCMB as the research object and tested its low-temperature charge and discharge characteristics. The results show that as the temperature drops, the discharge channel drops from 3.762V (0°C) to 3.207V (30°C); the total battery capacity also drops sharply from 78.98mAh (0°C) to 68.55mAh (30°C). 2. The low temperature characteristics of the spinel structure cathode material The spinel structure LiMn2O4 cathode material does not contain Co element, so it has the advantages of low cost and non-toxicity. However, the variability of Mn valence and the Jahn-Teller effect of Mn3+ lead to the structural instability and poor reversibility of this component. Peng Zhengshun and others pointed out that different preparation methods have a greater impact on the electrochemical function of LiMn2O4 cathode materials. Take Rct as an example: the Rct of LiMn2O4 composed of high-temperature solid phase method is significantly higher than that of sol-gel method, and this phenomenon is caused by lithium ion. There is also performance in the dispersion coefficient. The reason is that the different composition methods have a greater impact on the crystallinity and morphology of the product. 3. Low temperature characteristics of phosphate system cathode materials LiFePO4 has become the main body of current power lithium-ion battery cathode materials due to its excellent volume stability and safety, together with ternary materials. The poor low-temperature function of lithium iron phosphate is mainly due to the fact that the material itself is an insulator, low electronic conductivity, poor lithium ion dispersion, and poor conductivity at low temperatures, which increases the internal resistance of the battery, greatly affects the polarization, and hinders the charging and discharging of the battery. The low temperature function is not ideal. When studying the charging and discharging behavior of LiFePO4 at low temperature, Gu Yijie et al. found that the Coulomb power dropped from 100% at 55°C to 96% at 0°C and 64% at 20°C; the discharge voltage decreased from 3.11V at 55°C. To 2.62V at 20°C. Xing et al. used nano-carbon to modify LiFePO4 and found that after adding nano-carbon conductive agent, the electrochemical function of LiFePO4 is less sensitive to temperature, and the low-temperature function is improved; after modification, the discharge voltage of LiFePO4 is changed from that of 25℃. The drop from 3.40V to 3.09V at 25°C is only 9.12%; and the battery power at 25°C is 57.3%, which is higher than 53.4% u200bu200bwithout nano-carbon conductive agent. Recently, LiMnPO4 has attracted a lot of interest. The study found that LiMnPO4 has the advantages of high potential (4.1V), no pollution, low price, and large specific capacity (170mAh/g). However, due to the lower ion conductivity of LiMnPO4 than LiFePO4, Fe is often used in practice to partially replace Mn to form a LiMn0.8Fe0.2PO4 solid solution. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How to improve the safety and stability of the battery?