Ways to improve the high temperature operating performance of lithium batteries

Ways to improve the high-temperature performance of lithium batteries (1) Material improvement for lithium battery manufacturing Aiming at the problem of poor cycle performance of lithium batteries at high temperatures, anode materials can be modified to improve their cycle performance at high temperatures. At present, the modification of anode materials mainly includes bulk phase doping and surface modification. Methods to improve the high-temperature performance of lithium batteries include cation doping, anion doping, composite doping and so on. Cation doping is important for lithium manganate materials. After adding low-valent cations, the manganese element is partially substituted in the crystal, which increases its average valence and reduces the lattice constant, thereby reducing the dissolution of manganese. On the other hand, the binding strength of substituted cations and oxygen is higher than that of manganese ions and oxygen, making the structure more stable and inhibiting the occurrence of the jahn-teller effect. Commonly used doping cationic elements are aluminum, magnesium, iron, nickel and so on. Anion doping mainly includes F, Cr, s2* and so on. These electronegative anions are used to partially replace oxygen ions to improve the stability of the material. Compound doping refers to the doping of multiple cations and anions [21-]. The bulk doping method can improve the cycle performance of the battery to a certain extent, but it will lead to a decrease in the initial capacity of the lithium battery. So far, no ideal doping method has been found. The surface modification method can reduce the direct contact between the material and the electrolyte, reduce the specific surface area of u200bu200bthe material, and thereby reduce the dissolution of metal ions. The most common method is to use metal oxides, metal fluorides and stable anode materials to coat the material. In addition to modifying the anode material, graphite anode coating is also used to reduce the deposition of metal ions in the electrolyte on the surface of the anode. (2) Improvement of the electrolyte of lithium batteries The improvement of the electrolyte of lithium batteries is important to improve its cycle performance by changing conductive salts and using electrolyte additives. The presence of HF in the electrolyte is an important reason for the dissolution of the cathode material of the battery, so reducing the appearance of HF can reduce the dissolution of the cathode material. By using LiBOB lithium salt, the appearance of HF can be prevented, the dissolution of metallic iron can be reduced, and the high temperature cycle performance of lithium iron phosphate batteries can be improved. Use LiC104 conductive salt, LiBF4 and LiBOB mixed conductive salt to improve the high temperature cycle performance of lithium iron phosphate batteries. In addition, silane and other organic silicon water removal additives can be used to reduce the appearance of HF. In addition to preventing the dissolution of metal positive ions, it is also necessary to reduce the deposition of metal ions on the graphite surface in the electrolyte. There are two ways for additives to inhibit the deposition of metal ions on the graphite surface. One is to form a dense passivation film on the surface of the negative electrode to hinder the contact of metal ions with the graphite electrode and reduce the deposition of metal ions. The other is to inhibit the deposition of metal ions by combining them with the electrolyte. (3) The new binder The binder is an important part of the lithium battery electrode, which has an important influence on the battery performance. Compared with PVDF binder, CMC binder lithium battery has better cycle performance and multiplier performance. 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.