Preparation method of flame-retardant organic/inorganic composite membrane

Abstract

The invention discloses a preparation method of a flame-retardant organic / inorganic composite membrane. The method comprises the steps of preparing zirconium phosphate powder with a hexagonal structure by a time-temperature-concentration control method, organizing the prepared zirconium phosphate powder, stripping a multilayer structure to become a laminal filler as thin as possible, directly mixing an organized zirconium phosphate solution with a water-soluble binder solution, preparing coating pulp, coating the coating pulp on the surface of a polyolefin microporous membrane, drying the coating pulp, and obtaining the organic / inorganic composite membrane. The preparation method is used for preparing a membrane suitable for a high-power battery; the preparation method of the flame-retardant organic / inorganic composite membrane is simple in technology, low in equipment requirement, easy in condition control and low in cost, and is suitable for industrial production; the flame retardance of the membrane can be improved effectively by simple coating; an oxygen index is increased obviously; the flame-retardant grade reaches VTM-2; a demand of a battery membrane is met; and high performance of a common membrane is achieved.

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, select high temperature resistant resin such as patent CN 103441228A, select polyaryl sulfone amide, dissolve it with organic solvent and then prepare lithium ion by wet papermaking process Battery diaphragm, the patent CN 103205123A proposes to use polyphenylene sulfide and organic solvent to mix, co-extrude and then stretch and extract to obtain a porous film to prepare a diaphragm. Since the material itself is a flame-retardant material, its flame retardancy must be improved, but at the same time there is a price Expensive, with the drawback of organic contamination in the molding process

[0007] The second is to mix the flame retardant filler with the matrix resin to prepare the diaphragm, as mentioned in the patent CN 103700800A, to form a layer on the surface of the polypropylene fiber by the composite papermaking method The flame retardant layer is mixed with cotton fiber and flame retardant, but the flame retardant 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 to form a porous film. Although the method can improve the flame retardancy of the diaphragm, the uniformity of the pores is poor, and the phenomenon of membrane rupture is prone to occur.

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