Polyimide composite diaphragm, preparation method thereof and lithium ion battery

[0089] This embodiment provides a polyimide composite diaphragm, which includes a polyimide base film, a ceramic coating coated on one side of the polyimide base film, and a coating a meta-aramid polymer coating on the other side of the polyimide base film. The thickness of the polyimide composite diaphragm is 6 μm, the thickness of the ceramic coating is 2 μm, the thickness of the polymer coating is 2 μm, and the meta-aramid fiber glass in the meta-aramid coating The transition temperature is 400°C.

[0090] The preparation method comprises the following steps:

[0091] (1) will D 10 Particle size is 0.3μm, D 50 Particle size is 0.6μm, D 90 The particle size is 1.3μm and the specific surface area is 7m 230g boehmite (purity is 99.95%) and 45g deionized water per gram are stirred at high speed, the speed of stirring is 1000rpm, the time of stirring is 4h, and after stirring for 6h in the mode of magnetic stirring, ultrasonic dispersion 1h, at 30 After heating at ℃ for 0.5h,

[0095] This embodiment provides a polyimide composite diaphragm, which includes a polyimide base film, a ceramic coating coated on one side of the polyimide base film, and a coating a meta-aramid polymer coating on the other side of the polyimide base film. The thickness of the polyimide composite diaphragm is 8 μm, the thickness of the ceramic coating is 2.5 μm, the thickness of the polymer coating is 2.5 μm, and the meta-aramid in the meta-aramid coating The glass transition temperature is 320°C.

[0096] The preparation method comprises the following steps:

[0097] (1) will D 10 Particle size is 0.35μm, D 50 Particle size is 0.65μm, D 90 The particle size is 1.35μm and the specific surface area is 7.5m 2 35g boehmite / g and 70g deionized water were stirred at a high speed, the stirring rate was 1000rpm, the stirring time was 6h, and then stirred by magnetic stirring for 6h, ultrasonically dispersed for 1h, and heated at 35°C for 1.5h to After dissolving, add 2.5g propy

[0101] This embodiment provides a polyimide composite diaphragm, which includes a polyimide base film, a ceramic coating coated on one side of the polyimide base film, and a coating a meta-aramid polymer coating on the other side of the polyimide base film. The thickness of the polyimide composite diaphragm is 10 μm, the thickness of the ceramic coating is 2.2 μm, the thickness of the polymer coating is 2.2 μm, and the meta-aramid fiber in the meta-aramid coating The glass transition temperature is 260°C.

[0102] The preparation method comprises the following steps:

[0103] (1) will D 10 Particle size is 0.32μm, D 50 Particle size is 0.62μm, D 90 The particle size is 1.32μm and the specific surface area is 7.2m 2 20g alumina per gram and 60g deionized water were stirred at a high speed, the stirring rate was 800rpm, the stirring time was 9h, and then stirred by magnetic stirring for 6h, ultrasonically dispersed for 1h, heated at 20°C for 3h until dissolved Then add 1g of