High-sulfur supported lithium-sulfur battery positive electrode, preparation method of lithium-sulfur battery positive electrode, and lithium-sulfur battery

Abstract

The invention provides a preparation method of a high-sulfur supported lithium-sulfur battery positive electrode. The preparation method comprises the following steps: adding a carbon material and sulfur into water, and uniformly mixing to form carbon-sulfur mixed slurry; adding the carbon-sulfur mixed slurry into a sand mill for performing nano ball milling, drying and grinding, and heating and melting to obtain a carbon-sulfur composite positive electrode material; adding a conductive agent, an adhesive and the carbon-sulfur composite positive electrode material into water, and uniformly mixing to form a lithium-sulfur battery positive electrode slurry precursor, adding the positive electrode slurry precursor into the sand mill, and performing nano ball milling to obtain lithium-sulfur battery positive electrode slurry; uniformly coating an aluminum foil with the lithium-sulfur battery positive electrode slurry, and drying, thereby obtaining the high-sulfur supported lithium-sulfur battery positive electrode. The method disclosed by the invention is low in raw material cost, simple in technology and controllable in process, and the lithium-sulfur battery positive electrode with high sulfur supporting capacity is prepared. The invention further provides a lithium-sulfur battery positive electrode prepared by the method, and a lithium-sulfur battery assembled from the positiveelectrode.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a high-sulfur-loaded lithium-sulfur battery positive electrode, a preparation method thereof, and a lithium-sulfur battery. Background technique [0002] According to the national plan, the specific capacity of rechargeable and dischargeable lithium batteries should reach an energy density of more than 400Wh / kg in the past 30 years. However, limited by the theoretical specific capacity of traditional cathode materials such as lithium cobalt oxide and lithium iron phosphate, it is difficult to increase the energy density of traditional lithium-ion batteries to more than 300Wh / kg, so it is necessary to develop a new lithium battery system to reach more than 400Wh / kg . Lithium-sulfur batteries are currently recognized in the world as a new type of lithium battery that can be commercially applied in a short period of time and whose energy density can reach ...

AI Technical Summary

Problems solved by technology

[0003] It is difficult to coat the pole piece with high sulfur loading after simply stirring and mixing the active material, conductive agent and binder by conventional methods. Most of the literatures so far have reported that the sulfur loading is 1mg / cm 2 or so; although the reported specific capacities of these lithium-sulfur batteries are relatively high, in fact, the capacity that can be provided per unit area is small, which cannot meet the application requirements

However, although a small number of lithium-sulfur battery cathodes reported in the literature have high sulfur loading, the preparation process is relatively complicated, which is not conducive to the expansion of production.

For example, Chinese patent application CN201410208703.3 discloses a flexible high-sulfur-loaded self-healing positive electrode structure and its preparation method for lithium-sulfur batteries, mainly using graphene / polymer flexible foam as a sulfur carrier to increase the sulfur load; This method first needs to prepare a qualified graphene / polymer flexible foam, and then infiltrate sulfur into the carrier. On the one hand, the preparation of this flexible foam is difficult, and on the other hand, the technical difficulty of sulfur infiltration is relatively high. Large, may cause uneven distribution of sulfur, which is not conducive to expanding production

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