Preparation method of zinc sulfide and graphene oxide compound and application of compound to lithium-sulfur battery positive electrode material

Abstract

The invention belongs to the technical field of a new energy source material, and particularly relates to a preparation method of a zinc sulfide and graphene oxide compound and application of the compound to a lithium-sulfur battery positive electrode material. The preparation method is concretely characterized in that carbon disulfide and quadrol solution are stirred and mixed to obtain a mixed solution; oxidized graphene is added into a solvent to be subjected to ultrasonic treatment, and is then added into the mixed solution to obtain mixed liquid; a zinc nitrate solution is dropwise addedinto the mixed liquid; after the dropwise addition is completed, the mixed liquid is transferred into a kettle; reaction, cooling, centrifugal separation, washing and drying are performed; the compound material is obtained. Excessive metal sulfide ZnS is used as chemical adsorption and catalytic active sites of multi-sulfur ions; graphene oxide is a conductive substrate, so that the electroconductibility of the composite material is improved; the transfer and transmission of electrons on the ZnS and multi-sulfur ion interface are accelerated. Through chemical reaction sulfur carrying, the energy consumption is reduced; the active substance dispersion is uniform. The great sulfur carrying quantity reaching up to 90 percent is realized, so that the energy density of the battery is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of new energy materials, and in particular relates to a preparation method of zinc sulfide and graphene oxide composite material and its application in lithium-sulfur battery cathode materials. Background technique [0002] In today's society, energy shortage and environmental pollution make it urgent for people to develop and utilize new energy. However, regardless of the form of new energy, the conversion, storage and control of its energy requires a safe, cheap, efficient and long-life electrochemical system. At the same time, electric vehicles (EVs), hybrid electric vehicles The rapid development of (hev) and the application of large-scale renewable energy continue to enhance the demand for high energy / power density, high stability, long life, and low-cost batteries. Conventional lithium-ion batteries such as lithium cobaltate, lithium manganate and lithium phosphate as power sources have been unable to...

AI Technical Summary

Problems solved by technology

[0003] However, the practical application of lithium-sulfur batteries still faces severe challenges: (1) the simple substance S and the final discharge product Li 2 S 2 and Li 2 The low conductivity of S leads to low utilization of active materials, resulting in low capacity play

(2) Up to 78% volume change during cycling leads to loss of electrical contact and thus powdering and collapse of electrodes (3) Intermediate products formed during charge and discharge are easily dissolved into the organic electrolyte, causing the shuttle effect Occurs, which in turn leads to capacity fading and poor Coulombic efficiency, and eventually short-circuits the battery

[0004] In order to overcome the above problems, researchers have made a lot of efforts to combine elemental sulfur with porous conductive carbon materials, but this method can physically confine polysulfide ions, which cannot be effectively fixed during the long cycle; subsequent polarity The host material of the host material is used to chemically adsorb polysulfide ions, and recent breakthroughs have been made in the application of catalytically active sulfur host materials to promote the redox reaction of lithium polysulfide such as: research paper ( J. Am. Chem. Soc . 2015, 137 , 11542.) Pt / G electrode introduced, ( Energy Environment. Sci . 2017, 10 , 1476.) MoS in 2 / rGO electrode, etc., but the high cost of the catalyst and the limited catalytic active sites limit the loading of active material sulfur. The significant problem of the sulfur main body of the above catalysts is that the sulfur loading is only about 70%.

However, the low loading of active materials reduces the energy density of lithium-sulfur batteries in practical applications, which is not conducive to their practical applications.

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