A 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 an application thereof, belonging to the technical field of lithium-sulfur batteries, and specifically includes the following steps: preparation of a precursor cobalt-based ZIF‑67, sulfur doping Preparation of heterocobalt-based carbon nanocages, polypyrrole-coated sulfur-doped cobalt-based carbon nanocages (PS‑CNCs). By constructing a carbon nanocage to form an internal hollow structure, it can accommodate more active material sulfur, and limit the volume expansion of sulfur, effectively alleviate the volume expansion problem during the battery reaction process, and increase the service life; sulfur-cobalt co-doping can effectively improve PS‑ The interaction between CNCs and polar polysulfides in the reaction can effectively inhibit the shuttle effect of polysulfides and improve the battery cycle performance; the use of polypyrrole-coated carbon nanocages can significantly improve the conductivity of the material, reduce impedance, and inhibit polarity. to improve battery stability. The method of the invention has low cost, simple operation, obvious effect and is suitable for popularization.

Description

A kind of polypyrrole-coated sulfur-doped cobalt-based carbon nano-cage material, preparation method and same application technical field The invention belongs to lithium-sulfur battery technical field, be specifically related to a kind of polypyrrole-coated sulfur-doped cobalt-based carbon nano-cage material Materials, preparation methods and applications. Background technique [0002] The lithium-sulfur battery uses lithium metal as the negative electrode material, and common elemental sulfur is used as the positive electrode active material. The theoretical energy density is as high as 2600Wh / kg, far exceeding the traditional lithium-ion battery. Research and development of lithium-sulfur battery materials in new energy The field of source materials has become a research hotspot of great importance and urgency. [0003] The positive active material of traditional lithium-sulfur batteries is elemental sulfur, although it has high reserves, non-toxic, environmentally...

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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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