Vulcanized polymer composite material, positive pole piece containing vulcanized polymer composite material, and preparation method and application of vulcanized polymer composite material

Abstract

The invention provides a vulcanized polymer composite material, a positive pole piece containing the vulcanized polymer composite material and a preparation method and application of the vulcanized polymer composite material, and the preparation method comprises the following steps: (1) mixing a sulfur raw material and a conductive polymer to obtain mixed powder; and (2) carrying out firing and heat treatment on the obtained mixed powder to obtain the vulcanized polymer composite material, and the preparation method ensures that the obtained mixed powder has a fluffy characteristic in a powder dry mixing manner, can reduce material agglomeration generated in a sintering process and reduce the specific surface area of the material, so that the sulfur loading capacity of the prepared positive pole piece can be improved, support is provided for implementation of a high-energy-density lithium-sulfur battery, and the vulcanized polymer composite material has important research value.

Description

technical field [0001] The invention belongs to the technical field of lithium-sulfur batteries, and in particular relates to a vulcanized polymer composite material, a positive pole sheet containing the same, a preparation method and application thereof. Background technique [0002] Lithium-sulfur batteries have the advantages of high theoretical energy density, abundant and easy-to-obtain raw materials, and low prices. They can be widely used in aerospace and new energy vehicles and other fields, and are one of the main development directions of the next generation of high-energy batteries; lithium-sulfur batteries are At present, it is recognized that a new type of lithium battery with an energy density of more than 400Wh / kg can be achieved. However, there are still many obstacles in its commercialization process, such as the polysulfide shuttle effect, the problem of lithium dendrites in the negative electrode, and so on. From the perspective of improving the energy de...

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Problems solved by technology

Among them, sulfur-carbon composite materials mainly load elemental sulfur on a carbon carrier with rich pores. This kind of material is prone to shuttle effect due to the reaction of elemental sulfur to form polysulfides, which leads to battery capacity attenuation and affects cycle life.

Metal sulfide supports various metal sulfides on carbon supports. This kind of material has the same problem as sulfur-carbon composite materials: it is prone to shuttle effect

CN112194182A discloses a preparation method for the problems of slow electrode reaction kinetics, first coulombic efficiency and low specific capacity of the traditional chromium oxide positive electrode. The method is: preparation of chromium oxide; preparation of sulfurized polyacrylonitrile; Preparation of polyacrylonitrile; mixing the prepared lithiated sulfurized polyacrylonitrile and chromium oxide, and ball milling at 200rpm for 1 hour to obtain a chromium oxide positive electrode containing lithiated sulfurized polyacrylonitrile

[0005] However, the specific surface area of ​​the vulcanized polymer material prepared in the above-mentioned patent is relatively large, which affects the preparation of the subsequent high-capacity sulfur positive electrode sheet, and when the reaction between the sulfur raw material and the conductive polymer is insufficient, the product still has elemental substances Sulfur, which affects the cycle life of the battery

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