The development direction of lithium battery cathode materials

Lithium battery cathode material 1) Lithium titanate spinel-type lithium titanate is considered to be a cathode material with the following advantages: 1) Lithium titanate before and after delithiation is almost zero strain; 2) The intercalated lithium has a high potential (1.55v) ), prevent the appearance of lithium dendrites, and have high safety; 3) Have a very flat voltage platform; 4) High chemical diffusion coefficient and high Coulomb efficiency. Many advantages of lithium titanate determine that it has excellent cycle performance and high safety, but its electrical conductivity is not high, and the ability of high current charge and discharge attenuation is serious. Surface modification or doping is usually used to improve its electrical conductivity. . (2) As an ideal cathode material for lithium batteries, silicon-based materials have the following advantages: silicon can form a Li4.4Si alloy with lithium, and the theoretical storage capacity of lithium is as high as 4200mAh/g (more than 10 times the capacity of graphite); The intercalation potential (0.5v) of lithium is slightly higher than that of graphite, so it is difficult to form lithium dendrites during charging. The reaction activity of silicon and electrolyte is low, and no organic solvent co-encapsulation occurs. Carbon nanotubes Carbon nanotubes are a kind of carbon material with a graphitized structure and have good electrical conductivity. At the same time, due to the small depth and short stroke during delithiation, as a negative electrode material, the polarization effect is small during high-rate charge and discharge, which can improve the high-rate charge and discharge performance of lithium batteries. However, when carbon nanotubes are directly used as cathode materials for lithium batteries, problems such as large irreversible capacity, voltage lag, and unobvious discharge platform will occur. Carbon nanomaterials (carbon nanotubes and graphene) have the advantages of specific surface area, high conductivity, and chemical stability, and have potential applications in new lithium batteries. (4) Soft carbon Soft carbon, amorphous carbon that can be graphitized at high temperature (>-2500℃). The outstanding advantage of soft carbon materials is the high reversible specific capacity, generally greater than 300mAh/g, and better compatibility with organic solvents, so the lithium battery has good cycle stability and is more suitable for charging and discharging lithium batteries with high current density. Soft carbon refers to amorphous carbon that can be graphitized at high temperatures above 2500°C. The advantage of silene as a cathode material for lithium batteries Silene is a porous layered silicon material prepared by molecular beam epitaxy and solid-phase reaction. Since the bond length between silicon atoms in silylene is much greater than the bond length between carbon atoms in graphene, the arrangement of atoms in silylene has a twisted arrangement structure. Compared with the silicon material of the traditional diamond structure, the interlayer coupling effect of the silicon guest is Van der Waals force, which provides the interlayer between the lithium ion supply space to ensure that the silicon guest of the structure is not destroyed during the charging and discharging process, thereby preventing the problem of the electrode. A traditional silicon electrode material that expands in volume during charging and discharging. The stability and cycle times of the silylene anode material can be greatly improved. Compared with graphite, multilayer silicene has a larger lattice constant, and its theoretical capacity can reach about three times that of graphite. In addition, the silicon atoms and calcium atoms in the silicene prepared by the solid phase method are alternately arranged to form a layered structure, and the calcium atoms are removed by local chemical intercalation to obtain the substrate-free silicene. The silylene prepared by this method is used as the negative electrode of a lithium battery. It has the advantages of large capacity of silicon-based materials and good cycle characteristics of graphite materials, and has become a potential lithium battery negative electrode material. With the development of advanced materials and all-electric vehicles, the energy density of lithium batteries is constantly increasing. Silicon has a good specific capacity and is an ideal cathode material. Conclusion: In recent years, cathode materials for lithium batteries are developing in the direction of high specific capacity, long cycle life, and low cost. With the continuous expansion of lithium battery application scenarios and markets, the future market application prospects of lithium batteries as energy storage batteries will be broader. 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 article: How to buy a mobile power bank?