CN-122000619-A - Separator, electrochemical device and electronic apparatus including the same

CN122000619ACN 122000619 ACN122000619 ACN 122000619ACN-122000619-A

Abstract

The invention discloses a diaphragm, an electrochemical device and electronic equipment containing the diaphragm, wherein the diaphragm comprises a base film and a composite material layer on at least one surface of the base film, the composite material layer comprises a polyurethane substrate and a filler dispersed in the polyurethane substrate, and the filler comprises ceramic and polydopamine coated on the surface of the ceramic. The separator has excellent electrolyte wettability, thermal stability and ionic conductivity.

Inventors

LIU MINGQIAN
ZHANG HONGCHEN
LIU YILING
Tong Lintai

Assignees

远景动力技术(江苏)有限公司
远景睿泰动力技术(上海)有限公司

Dates

Publication Date: 20260508
Application Date: 20241105

Claims (10)

1. A separator comprising a base film and a composite layer on at least one surface of the base film; the composite material layer comprises a polyurethane substrate and a filler dispersed in the polyurethane substrate, wherein the filler comprises ceramic and polydopamine coated on the surface of the ceramic.
2. The separator of claim 1, wherein the polyurethane substrate satisfies one or more of the following conditions (a) - (c): (a) The polyurethane substrate is made of polyether polyurethane and/or polyester polyurethane; (b) The tensile strength of the polyurethane substrate is 25-50MPa; (c) The mass content of the polyurethane substrate in the composite material layer is 30% -75%.
3. The separator of claim 2, wherein the polyurethane substrate satisfies one or both of the following conditions (a) - (d): (a) The weight average molecular weight of the polyether polyurethane is 5000-20000; (b) The weight average molecular weight of the polyester polyurethane is 5000-20000; (c) The content of the hard segment of the polyether polyurethane is 10% -40%, and the content of the soft segment of the polyether polyurethane is 60% -90%; (d) The content of the hard segment of the polyester polyurethane is 10% -40%, and the content of the soft segment of the polyester polyurethane is 60% -90%; (e) The polyester polyurethane is polycarbonate polyurethane.
4. The separator of claim 1, wherein the separator meets one or more of the following conditions (a) - (f): (a) The material of the base film is polyolefin; (b) The thickness of the base film is 5-30 mu m; (c) The porosity of the base film is 30% -60%; (d) The thickness of the composite material layer is 2-5 mu m; (e) The ceramic comprises one or more of silica, alumina, zirconia, titania, calcium oxide, boehmite, hydrotalcite, barium carbonate and magnesium hydroxide; (f) The composite layer further includes a binder, a dispersant, and a wetting agent.
5. The separator of claim 4, wherein the separator satisfies one or more of the following conditions (a) - (d): (a) The polyolefin is polyethylene and/or polypropylene; (b) The binder comprises polyvinylpyrrolidone and/or polyacrylic acid compound; (c) The dispersing agent comprises one or more of polyethylene glycol, sodium polyacrylate and ammonium polyacrylate; (d) The wetting agent comprises one or more of an alkynol surfactant, a polyol ester surfactant and a silanol surfactant.
6. The separator according to any one of claims 1 to 5, wherein the method of preparing the separator comprises the steps of: The preparation method of the composite material comprises the following steps of mixing ceramics and dopamine monomers to obtain a polydopamine coated ceramic material, mixing the polydopamine coated ceramic material with polyurethane solution and drying to obtain the composite material.
7. The separator of claim 6, wherein the separator is prepared by a process that satisfies one or more of the following conditions (a) - (e): (a) The mass ratio of the ceramic to the dopamine monomer is 1 (1-5); (b) The mass concentration of polyurethane in the polyurethane solution is 5% -10%; (c) The organic solvent of the polyurethane solution comprises one or more of DMF, DMSO, THF, NMP, acetone and ethyl acetate; (d) The mass ratio of the polydopamine coated ceramic material to polyurethane in the polyurethane solution is 1 (1.2-4.5); (e) The preparation method of the composite material slurry comprises the following steps of mixing a binder, a dispersing agent, a wetting agent, a solvent and the composite material to obtain the composite material slurry.
8. The separator of claim 6, wherein the separator is prepared by a process that satisfies one or more of the following conditions (a) - (d): (a) The mass concentration of the composite material in the composite material slurry is 25% -60%; (b) The mass concentration of the binder in the composite material slurry is 5-12%; (c) The mass concentration of the dispersing agent in the composite material slurry is 0.5% -5%; (d) The mass concentration of the wetting agent in the composite material slurry is 0.1% -1%.
9. An electrochemical device comprising the separator according to any one of claims 1 to 8.
10. An electronic device characterized in that it comprises the electrochemical device according to claim 9.

Description

Separator, electrochemical device and electronic apparatus including the same Technical Field The present invention relates to a separator, and an electrochemical device and an electronic apparatus including the same. Background At present, polyolefin separators (mainly PP and PE) are widely applied to lithium ion batteries due to the characteristics of high mechanical strength, good electrochemical stability, small pore diameter and low cost. However, the polyolefin membrane commonly used at present has poor high-temperature stability (the melting point of the PE membrane is 125-140 ℃ and the melting point of the PP membrane is 165-170 ℃), and the size change can occur at high temperature to cause contact between the anode and the cathode, so that internal short circuit is caused, thereby bringing about safety risk. In addition, the problems of poor electrolyte wettability and low electrolyte absorptivity of the polyolefin separator can also lead to low ionic conductivity and high internal resistance of the battery, and have great influence on the electrochemical performance of the lithium ion battery. With the increasing demands of people on high-performance lithium ion batteries, the inherent defects of polyolefin separators limit the application development of the polyolefin separators in the field of high-performance lithium ion batteries. Disclosure of Invention In order to solve the defects of poor wettability, thermal stability and ionic conductivity of diaphragm electrolyte in the prior art, the invention provides a diaphragm, an electrochemical device and electronic equipment containing the diaphragm. The separator has excellent electrolyte wettability, thermal stability and ionic conductivity. In order to achieve the above object, the present invention adopts the following technical scheme. In a first aspect, the present invention provides a separator characterized in that it comprises a base film and a composite layer on at least one surface of the base film; the composite material layer comprises a polyurethane substrate and a filler dispersed in the polyurethane substrate, wherein the filler comprises ceramic and polydopamine coated on the surface of the ceramic. In a second aspect, the invention provides an electrochemical device characterized in that it comprises a separator as described above. In a third aspect, the present invention provides an electronic device comprising an electrochemical device as described above. The invention has the positive progress effects that: The invention provides a diaphragm, which is formed on a base film, wherein the composite material layer contains a polydopamine coated ceramic material, so that the thermal stability of the diaphragm can be effectively improved, the electrolyte wettability of the diaphragm can be improved, the polydopamine coated ceramic material is dispersed in a cross-linked network structure provided by a polyurethane substrate, and the polyurethane substrate has two incompatible soft and hard sections, so that on one hand, the mechanical strength and the thermal stability can be provided, and on the other hand, the ionic conductivity can be provided, and the diaphragm formed by the composite material layer and the base film has excellent electrolyte wettability, thermal stability and ionic conductivity and can be used for designing a high-group-margin cell. Drawings FIG. 1 is a schematic structural view of the separator of examples 1 to 24. The reference numerals are as follows: 1-basement membrane, 2-polyurethane basement, 3-polydopamine and 4-ceramic. Detailed Description The invention is further illustrated by means of the following examples, which are not intended to limit the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications. Diaphragm In the separator according to the first aspect of the present invention, it includes a base film and a composite material layer on at least one surface of the base film; the composite material layer comprises a polyurethane substrate and a filler dispersed in the polyurethane substrate, wherein the filler comprises ceramic and polydopamine coated on the surface of the ceramic. In certain embodiments, the polyurethane substrate material is polyether polyurethane and/or polyester polyurethane. In some embodiments, the polyether polyurethane has a weight average molecular weight of 5000 to 20000. In a specific embodiment, the polyether polyurethane has a weight average molecular weight of 12000. In some embodiments, the polyester polyurethane is a polycarbonate polyurethane. In some embodiments, the polycarbonate-type polyurethane has a weight average molecular weight of 8000. In some embodiments, the polycarbonate-type polyurethane has a molecular weight of 5000 to 20000. In some embodiments, the hard segment content of the