Application of Boehmite in Lithium Batteries
The boehmite coating can significantly improve the thermal stability of the separator, improve the safety of lithium batteries, and improve the rate performance and cycle performance of the battery under the premise of a lower coating thickness. At the same time, the thinner coating thickness Helps to improve the volumetric energy density and gravimetric energy density of lithium-ion batteries. Alumina is more widely used in diaphragms, but it is worth noting that the hardness of alumina is relatively large, so in the process of cutting and coating, the mechanical wear is large, and the cost is relatively low compared to boehmite. High, and boehmite has the characteristics of high heat resistance temperature, good compatibility with organic matter, low hardness can reduce mechanical wear, and has advantages in cost.
Boehmite has great advantages in the lithium battery separator. The lithium battery separator of PP/PE material is a through hole. When the current is too large, it is easy to cause perforation, which will cause the lithium battery to burn or explode. Aluminum or boehmite can be used as a coating material together with a binder to adjust the pores. This is because high-purity alumina and boehmite have a plate-like crystal structure. When it is too large, the material will heat up, and then the high-purity alumina or boehmite coating material with a plate-like crystal structure will expand in volume, which will close the current conduction holes on the lithium battery separator, thereby blocking the current. When the temperature drops, the volume of the material will shrink, and the current conduction holes on the diaphragm will reopen.
Using the special physical and chemical properties of the material, the safety performance of lithium batteries can be greatly improved, thus providing high-efficiency lithium batteries with high power. Energy safety and safe and reliable charging and discharging provide the possibility. High-purity alumina or boehmite materials also have very good thermal conductivity. When the battery temperature is too high, this material can conduct heat transfer well, thus solving the problem of poor thermal conductivity of PP/PE materials. The boehmite material also has excellent flame retardancy, because the boehmite material itself is a very good flame retardant. Large-scale burning or even explosion.
