Advanced porous polymer nanosheet, preparation method and application thereof

Abstract

The invention discloses an advanced porous polymer nanosheet, a preparation method and application thereof. According to the invention, a zero-dimensional silicon dioxide molecular brush and a two-dimensional graphene molecular brush are prepared on the surfaces of zero-dimensional silicon dioxide and two-dimensional graphene by utilizing a polymer surface grafting technology, a co-assembly reaction is induced through cross-linking of the zero-dimensional silicon dioxide molecular brush and the two-dimensional graphene molecular brush, and then silicon dioxide is etched to obtain the porous polymer nanosheet, wherein a large number of polymer nanospheres with hierarchical pore structures are uniformly distributed on the surface of the prepared nanosheet, so that enough buffer space can be provided for volume change in conversion of sulfur active substances in the charging and discharging process of the lithium-sulfur battery, and graphene serving as a conductive trunk of the nanosheet can promote rapid transfer of charges so as to improve the conductivity of the electrode; the cross-linking induced co-assembly strategy can generate a large number of strong polar groups in the porous polymer skeleton, and can effectively inhibit the diffusion and loss of polysulfide; and the nanosheet shows excellent multiplying power and cycle performance when being used for a positive electrode material of a lithium-sulfur battery.

Description

technical field [0001] The invention belongs to the field of nanometer materials and lithium-sulfur batteries, and relates to a preparation method of an advanced porous polymer nanosheet, and the material can be applied to high-performance lithium-sulfur batteries. Background technique [0002] Porous polymer materials, due to their all-organic structural composition, large specific surface area, customizable pore structure, high stability, diverse synthesis strategies, and adjustable chemical components, are widely used in water treatment, gas adsorption, separation, catalysis, Energy storage, porous carbon material precursors, and optoelectronics have attracted continuous attention. Porous polymeric framework materials (e.g., conjugated microporous polymers, covalent organic frameworks) are of great interest in solving lithium-sulfur complexes due to their appropriate pore surface chemical environment, pre-designed polymer frameworks, and good affinity for lithium polysulf...

AI Technical Summary

Problems solved by technology

[0003] However, the current sulfur electrode materials based on porous polymers face the following problems that limit their practical application: First, because the existing porous polymer sulfur cathode materials are mainly microporous, it is not conducive to the formation of sulfur in the charging and discharging process. The volume change in the conversion of the active material provides enough buffer space, resulting in a low sulfur content (<60wt%) in the positive electrode material; secondly, the polarity of the functional group of the porous polymer is moderately weak and can only be reduced to a small extent. reduce the loss of sulfur active species

In addition, the conductivity of porous polymers is usually poor, which further limits the utilization of sulfur and leads to poor rate performance of lithium-sulfur batteries.

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