Three technologies to improve the voltage performance of lithium battery cathode materials -Lithium - Ion Battery Equipment
Increasing the voltage of the positive electrode data of lithium-ion batteries is a new idea to improve the energy density of lithium-ion batteries in recent years. The high-voltage data include two kinds of cathode data: spinel-like crystal structure and olivine-like crystal structure. LiMPO4(M=Co,Ni) is a typical high-pressure olivine crystal structure. Among them, the discharge potential of LiCoPO4 is 4.8v, the discharge potential of LiNiPO4 is 5.2v, and the theoretical capacity is close to 170mAh/g.(Lithium - Ion Battery Equipment)
5.2v is currently the highest charging and discharging voltage, because there is no electrolyte out of the game, there is no reported lithium-ion battery function LiNiPO4 positive electrode data, there are more LiCoPO4 data reported, but the cycle charge and discharge function of LiCoPO4 data is poor in the current electrolyte system .
The main side uses of olivine crystal structure under high pressure are: 1. The positive electrode data reacts with the electrolyte to form a solid-liquid interface layer; 2.2. The electrolyte will partially dissolve Co ions, seriously affecting the cycle charge and discharge function of the lithium-ion battery; 3. Poor conductivity and low conductivity. Therefore, the selection of the high-pressure olivine crystal structure must implement the necessary techniques to enhance its functionality, and there are three techniques.
1. Nanotechnology. Nanoparticles for active materials have shorter lithium ion and electron transport and diffusion pathways than micron-sized particles.
2. Stimulants. Unlike the spinel crystal structure, which can be doped with cations and anions at the same time, the olivine crystal structure can only improve the conductivity of positive electrode data by doping cations.
3. Coating. The amorphous carbon coating can form interconnected electron high-speed transport channels, thereby improving its functions, especially the first discharge capacity and charge-discharge cycle function.
LiMPO4 In general, the olivine-like crystal structure (M=Co, Ni) has more theoretical capabilities than the spinel-like crystal structure, but due to the low electrical conductivity and poor blood circulation function, the developed lithium-ion battery cathode The materials have no spinel-like crystal structure in the research achievements of lithium-ion batteries, and the input to the stage of industrialization requires more advanced functions to be transformed into skills. The first is electric vehicle power lithium-ion batteries.