The Advantages of Boehmite
The main advantages of boehmite products are particle size distribution, purity, and control of magnetic substances. And AVANT can produce 0.3-0.5 micron boehmite products, the smaller the particle size, the more difficult it is to produce.
Boehmite with high purity and high heat resistance temperature is a new type of inorganic lithium battery coating material. Alumina powder can be prepared after calcination.
At present, the boehmite/alumina coating has good flatness, air permeability, tensile and puncture strength.
(1) From the range of areal density: boehmite (±2) < PVDF (±3), indicating that its flatness is better, the areal density is more uniform, and the consistency is good;
2) From the perspective of air permeability: for the base film of 7 and 9 μm, although the thickness of the boehmite coating is 3 μm and the thickness of the PVDF layer is only 2 μm, the air permeability of boehmite is still better than that of PVDF, indicating that its unit gas passes through the diaphragm. The shorter the time, the smaller the internal resistance, which is conducive to the passage of lithium ions and ensures the rate of lithium ion batteries;
3) From the perspective of tensile strength and puncture strength: due to the different thicknesses of boehmite and PVDF coatings, they cannot be directly compared. Selecting the same base film and coating thickness for comparison, the tensile strength and puncture strength of the boehmite diaphragm are better than those of the mixed-coated diaphragm.
In addition to the use of boehmite for separator coating, the pole piece coating market is also gradually emerging. Coating in the pole piece of the lithium battery can avoid the burr generated during the slitting process of the positive electrode material from piercing the separator, improve the safety performance of the lithium battery, improve the battery production process, and increase the energy density.
The boehmite used in the pole piece coating material requires a larger particle size.
