Polypyrrole-coated sulfur-doped cobalt-based carbon nanocage material, preparation method and application thereof

Abstract

The invention discloses a polypyrrole-coated sulfur-doped cobalt-based carbon nanocage material, a preparation method and application thereof, and belongs to the technical field of lithium-sulfur batteries. The method specifically includes the following steps: preparation of a precursor cobalt-based ZIF-67, preparation of sulfur-doped cobalt-based carbon nanocages, and preparation of polypyrrole-coated sulfur-doped cobalt-based carbon nanocages (PS-CNCs). By forming an internal hollow structure in the carbon nanocages, it is possible to contain more active material sulfur and restrict the volume expansion of sulfur, thereby effectively alleviating the volume expansion during a battery reaction, and extending a service life. The co-doping of sulfur and cobalt can effectively improve the interaction of the PS-CNCs and polar polysulfides in a reaction can effectively inhibit the shuttle effect of the polysulfide and improve the cycle performance of the battery. The use of the polypyrrole-coated carbon nanocages can significantly improve the conductivity of the material, reduce the impedance, inhibit polarization, and improve battery stability. The method of the invention has low cost,simple operation and an obvious effect, and is suitable for popularization.

Description

technical field [0001] The invention belongs to the technical field of lithium-sulfur batteries, and in particular relates to a polypyrrole-coated sulfur-doped cobalt-based carbon nanocage material, a preparation method and an application thereof. Background technique [0002] Lithium-sulfur batteries use metal lithium as the negative electrode material and common elemental sulfur as the positive electrode active material. The theoretical energy density of the full battery is as high as 2600Wh / kg, far exceeding the traditional lithium-ion battery. The research and development of lithium-sulfur battery materials has become a very important and urgent research hotspot in the field of new energy materials. [0003] The positive active material of the traditional lithium-sulfur battery is elemental sulfur. Although it has the advantages of high reserves, non-toxic and environmentally friendly, and low price, it still has many shortcomings due to its own limitations: (1) During t...

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Problems solved by technology

[0003] The positive active material of the traditional lithium-sulfur battery is elemental sulfur. Although it has the advantages of high reserves, non-toxic and environmentally friendly, and low price, it still has many shortcomings due to its own limitations: (1) During the battery reaction process, the electric field and Under the concentration gradient, the discharge intermediate product polysulfide will produce a shuttle effect, resulting in serious capacity loss; (2) in the continuous charge and discharge process due to the large density difference between the elemental sulfur and the final discharge product will cause a large (3) The conductivity of elemental sulfur and the final product of discharge is poor, which is not conducive to electron transfer, resulting in a decrease in the utilization of active materials

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