A lithium-sulfur battery diaphragm and preparation method thereof

Abstract

The invention discloses a separator for a lithium-sulfur battery, comprising: a conductive layer composed of a conductive carbon material, flaky tungsten disulfide and a first binder, an insulating layer composed of a second binder, and the insulating layer is arranged on One side of the conductive layer; the conductive layer is used to limit the shuttle effect of polysulfides, and provides sufficient space and sites for the nucleation and growth of sulfur, and the insulating layer is used to block the positive and negative electrodes. Direct contact and short circuit between them, while improving the mechanical strength of the separator, is beneficial to the large-scale production and application of the separator. The invention also discloses a preparation method of a lithium-sulfur battery diaphragm. The first binder and the second binder are initially dissolved in acetone, and then the first binder is dissolved by adding N-methylpyrrolidone or heating. Melting with the second binder into a long-chain structure, reducing the crystallinity of the separator and improving the mechanical properties of the separator.

Description

technical field [0001] The invention relates to the technical field of lithium-sulfur batteries, in particular to a lithium-sulfur battery diaphragm and a preparation method thereof. Background technique [0002] In recent years, more and more new energy electric vehicles have been used in people's daily life, and the state has also vigorously supported and promoted the marketization and application of new energy electric vehicles. Low-cost, high-energy-density lithium-sulfur batteries are well suited to the needs of electric vehicles. At present, lithium-sulfur batteries have a small range of applications in European and American countries, which is entirely due to the extremely high theoretical energy density (1675mAh / g) of lithium-sulfur batteries. Lithium-sulfur batteries, which use earth-abundant and high-capacity sulfur as the positive electrode (cathode) and lithium as the negative electrode (anode), are the most promising and important components for integrating low...

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Problems solved by technology

[0003] The phase inversion method is a common method for preparing lithium-sulfur battery separators. Its advantages are simple process, low cost, and easy operation. The obtained film has high liquid absorption rate, good conductivity, and can be used with many organic solvents. It has high compatibility and is considered an ideal membrane material, but its disadvantages are poor mechanical strength and rate performance

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