Lithium-sulfur battery porous positive electrode and preparation method and application thereof

Abstract

The invention belongs to the technical field of lithium-sulfur batteries, and particularly relates to a preparation method of a porous positive electrode of a lithium-sulfur battery. Part of sulfur isloaded into a porous carbon material in advance through primary positive sulfur loading, the other part of sulfur serving as a pore forming agent and positive electrode slurry are mixed and coated ona current collector to prepare a pole piece, and secondary sulfur loading is performed under a positive pressure condition after rolling, so that the lithium-sulfur battery positive plate with certain compaction density and rich pores is obtained. The preparation method makes up the defects that the sulfur-carbon material has too many holes and poor electronic conductivity when the existing lithium-sulfur battery pole piece is not rolled; and the contradiction of poor ionic conductivity of the pole piece due to the fact that holes of the sulfur-carbon material are completely compacted duringrolling and electrolyte cannot infiltrate is avoided, so that the preparation of the lithium-sulfur battery porous pole piece with high sulfur loading capacity, high electronic conductivity and high ionic conductivity is realized.

Description

technical field [0001] The invention relates to the field of lithium-sulfur batteries, in particular to a method for preparing a porous positive electrode of a lithium-sulfur battery. Background technique [0002] Lithium-sulfur battery is an energy storage system that realizes the mutual conversion of electrical energy and chemical energy through the electrochemical cleavage and rebonding of sulfur-sulfur bonds. It utilizes S / Li 2 The two-electron gain-loss reaction of S interconversion can obtain a positive electrode specific capacity of about 1670mAh / g. The theoretical specific energy of a lithium-sulfur battery with a sulfur positive electrode and a lithium negative electrode can reach 2600Wh / kg, which is 3-5 times that of the current commercial lithium-ion battery. At the same time, the sulfur cathode has the advantages of abundant resources, low cost, and environmental friendliness, making lithium-sulfur batteries one of the most promising high-energy-density secondar...

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Problems solved by technology

[0006] In view of the above problems, the present invention proposes a method for preparing a porous positive electrode of a lithium-sulfur battery, the purpose of which is to use the secondary sulfur-loading technology to solve the problems of high sulfur loading, high electronic conductivity and high ion conductivity in the positive electrode of lithium-sulfur batteries. The problem of incompatibility of the three

The inventors found that in order to successfully prepare a porous positive electrode with excellent electrical properties, it is necessary to solve the problem that the high sulfur loading capacity, high electronic conductivity and high ion conductivity of the positive electrode sheet of lithium-sulfur battery cannot be coordinated

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