The application characteristics of silica specifically used for battery separators

Silica has a high content of characteristics, uniform particle size and excellent activity. Adding a certain proportion of battery-specific silica to batteries can significantly enhance their electrochemical performance, such as mechanical properties, conductivity, elongation at break, cycle performance, and lifespan. Therefore, silica has high application value in the battery field.
Silicon dioxide can reduce the crystallization rate of polymer systems, enabling them to remain in an amorphous phase for a longer time.
The granular silica between the positive and negative plates can maintain the consistency of the electrolyte in the battery and the holes through which oxygen can pass, significantly reducing the dry water failure.
3. The introduction of silica through in-situ compounding is beneficial to improving the electrical conductivity of P(VDF-HFP) -based microporous polymer electrolytes.
4. Silica particles can absorb moisture from the liquid electrolyte, reducing interfacial reactions.
5. By adding silica powder to polymer lithium batteries, the microstructure and mechanical and electrical properties of the electrolyte membrane can be greatly improved, making the electrolyte separator have excellent electrical conductivity and mechanical strength.
6. The colloidal electrolyte prepared with silica has strong gel-forming ability, suitable viscosity, and forms a soft colloidal electrolyte with good thixotropy. The three-dimensional network structure of the colloid is moderate, with low resistance, large discharge current, high capacitance, and no hydration or stratification. Moreover, it can significantly increase the cycle life of the colloid.
Adding silica to the separator can increase the pore size and the total amount of colloidal electrolyte. Effectively prevent the stratification of the electrolyte, reduce the corrosion rate and increase the service life. Adding silicon dioxide can enhance the tensile strength of the partition and reduce its pore size. When the pressure on the partition is greater than 30kPa, the liquid absorption capacity of the partition with added silica exceeds that of the pure glass wool partition.

The secondary lithium battery separator made by adding silicon dioxide to the composite polymer has a high liquid absorption rate, electrical conductivity and toughness. The electrolyte absorption rate reaches 184.4%, the room-temperature electrical conductivity is 1.20mS/cm, and the elongation at break is as high as 163%. The first discharge specific capacity of the secondary lithium battery assembled with the composite polymer separator containing silicon dioxide is 834.8mAh/g, the specific capacity of the 40th discharge reaches 400mAh/g, and the cycle efficiency reaches more than 99.8%, demonstrating excellent electrochemical performance.