Analyze the structure and characteristics of ternary lithium cathode materials

Ternary materials have been a hot spot in the past few years. Among them, the Ni component can increase the activity of the material and increase the energy density; the Co component is also an active material, which can stabilize the layered structure of the material and reduce the mixing of cations, which is convenient for the deep discharge of the material. , Thereby improving the discharge capacity of the material; Mn component plays a supporting role in the material, providing stability during the charge and discharge process. Ternary lithium basically embodies the advantages of several materials. Under the big category of ternary materials, the proportions of the three metal elements in the materials are different, which can be regarded as different kinds of ternary materials. One type is Ni:Mn equivalent type, and the second type is Ni:Mn unequal type. Representatives of the equivalent type are NCM424 and NCM111. During the charging and discharging process, the +4 valence of Mn does not change its valence and serves to stabilize the structure in the material. The +2 valence of Ni becomes +4 valence, losing two electrons, making the material have a high specific capacity. The unequal amounts of Ni and Mn are the protagonist of this article. They are also called high-nickel ternary lithium. The most important representative models are NCM523, NCM622 and NCM811. When the voltage platform of nickel-rich ternary materials is lower than 4.4V (related to Li+/Li), it is generally believed that the important thing is that Ni is +2/+3 valence to participate in the redox reaction, and the valence rises to +4. When the voltage is higher than 4.4V, Co3+ participates in the reaction to become +4 valence, and Mn4+ does not participate in the reaction to stabilize the structure. Disclaimer: Some pictures and content of the articles published on this site are from the Internet, please contact to delete if there is any infringement. Previous: How to improve the service life of lithium batteries