A kind of graphene oxide composite non-woven fabric and its preparation method and application

Abstract

A graphene oxide composite non-woven fabric and its preparation method and application relate to non-woven fabrics. The graphene oxide composite non-woven fabric is provided with a non-woven fabric base material, pours a slurry inside the non-woven fabric base material, or coats a slurry layer on the surface of the non-woven fabric base material; the slurry is made of graphene oxide or The graphene oxide blend is composed of a graphene oxide blend, a binder and a solvent, and the graphene oxide blend is composed of graphene oxide, a polymer and an inorganic substance. Preparation method: (1) mix graphene oxide or graphene oxide blend, binder and solvent, and ball mill to obtain slurry; (2) pour slurry into non-woven fabric substrate or coat it on non-woven fabric After the surface of the substrate is dried, the graphene oxide composite non-woven fabric is obtained. The graphene oxide composite non-woven fabric can be applied in the preparation of lithium-sulfur batteries, and the application is that the graphene oxide composite non-woven fabric is used as a diaphragm in the lithium-sulfur battery.

Description

technical field [0001] The invention relates to non-woven fabrics, in particular to a graphene oxide composite non-woven fabric and its preparation method and application. Background technique [0002] At present, chemical power systems using liquid electrolytes, such as lithium-ion batteries, need to use diaphragm materials to block the positive and negative electrodes to avoid short circuits. The diaphragm material is mainly composed of polyethylene (Polyethylene, PE), polypropylene (Polypropylene, PP), polytetrafluoroethylene (Polytetrafluoroethylene, PTFE) and other polymer films containing microporous structures, non-woven fabrics and electrospun fabrics. Silk septum. Liquid electrolyte (generally a carbonate organic solvent containing electrolyte salt) exists in the microporous structure to realize the conduction of ions between the positive and negative electrodes. The separator and liquid electrolyte constitute the electrolyte system. [0003] With the development...

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Problems solved by technology

[0005] First, the electronic conductivity and ionic conductivity of elemental sulfur are poor, and the conductivity of sulfur materials at room temperature is extremely low (5.0×10 -30 S cm -1 ), the final product of the reaction Li 2 S 2 and Li 2 S is also an electronic insulator, which is not conducive to the high rate performance of the battery

[0006] Second, the intermediate discharge products of lithium-sulfur batteries will dissolve into the organic electrolyte, increasing the viscosity of the electrolyte and reducing the ion conductivity

[0007] Third, the final discharge product of lithium-sulfur batteries, Li 2 S n (n=1~2) Electronic insulation and insoluble in the electrolyte, deposited on the surface of the conductive framework; part of the lithium sulfide detaches from the conductive framework, and cannot react into sulfur or higher-order polysulfides through a reversible charging process, resulting in Great attenuation of capacity

[0008] Fourth, the densities of sulfur and lithium sulfide are 2.07 and 1.66 g cm respectively -3 , there is a volume expansion / contraction of up to 79% during the charge and discharge process, which will lead to changes in the morphology and structure of the positive electrode, resulting in the detachment of sulfur from the conductive framework, resulting in capacity attenuation; this volume effect is in the button battery It is not significant, but in large batteries, the volume effect will be enlarged, which will cause significant capacity fading, which may cause damage to the battery, and the huge volume change will destroy the electrode structure

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