A preparation method of flame-retardant organic/inorganic composite diaphragm

Abstract

The invention discloses a method for preparing a flame-retardant organic / inorganic composite diaphragm. The method adopts a time-temperature-concentration control method to prepare zirconium phosphate powder with a hexagonal structure; The layer structure becomes as thin as possible sheet filler; the organic zirconium phosphate solution is directly mixed with the water-soluble binder solution to prepare the coating slurry; the coating slurry is coated on the polyolefin microporous membrane Surface, drying, to obtain the organic / inorganic composite diaphragm; prepare a diaphragm suitable for high-power batteries; its preparation method is simple in process, low in equipment requirements, easy to control conditions, low in cost, and suitable for industrial production; simple coating can Effectively improve the flame retardancy of the separator, the oxygen index is significantly improved, and the flame retardancy level reaches VTM‑2, while meeting the needs of battery separators and realizing the high performance of ordinary separators.

Description

technical field [0001] The invention belongs to the technical field of high-performance diaphragm preparation for lithium battery diaphragms, and in particular relates to a method for preparing a flame-retardant organic / inorganic composite diaphragm. Background technique [0002] As an important part of lithium-ion batteries, separators have attracted extensive attention from researchers. The high performance of lithium-ion batteries is closely related to the properties of separators. Especially in lithium batteries with high rate and fast charge and discharge, the performance requirements of separators are more obvious. In view of the fact that the separator has a crucial impact on the performance of the actual battery, it must have good chemical and electrochemical stability and maintain a high degree of wettability to the electrolyte during repeated charge and discharge. The interface phase between the separator material and the electrode Both the capacitive capacity and ...

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Problems solved by technology

[0006] One is to start with the material itself and select high-temperature resistant resins, such as patent CN 103441228A, select polyarylsulfone amide, dissolve it in an organic solvent, and then use a wet papermaking process to prepare lithium-ion battery separators. Patent CN 103205123A proposes the use of polyphenylene sulfide and organic solvents After mixing, co-extrusion, stretching and extraction to obtain a porous membrane to prepare a diaphragm, since the material itself is a flame-retardant material, its flame retardancy must be improved, but at the same time, it is expensive and has the defects of organic pollution during the molding process.

[0007] The second is to mix the flame retardant filler with the matrix resin to prepare the diaphragm. For example, the patent CN 103700800A mentions that a composite papermaking method is used to form a flame retardant layer mixed with cotton fibers and flame retardants on the surface of polypropylene fibers. The combustion effect is limited; for example, patents CN 103242591A and CN 102376928B all mention that the flame retardant powder is mixed with polypropylene and then extruded and stretched to form a porous film. Although this method can improve the flame retardancy of the diaphragm, the uniformity of the pores Poor, prone to membrane rupture

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