Preparation method of graphene/poly-anthraquinone thioether/sulphur composite cathode material

Abstract

The invention provides a preparation method of a graphene / poly-anthraquinone thioether / sulphur composite cathode material. The preparation method comprises the following steps: (1) dissolving sodium sulfide and elemental sulfur into distilled water to obtain an orange solution, adding Triton X-100, adding concentrated hydrochloric acid and gradually forming a yellow suspension liquid; (2) adding graphite oxide to the distilled water for ultrasonic treatment, obtaining a graphene oxide solution and adding the yellow suspension liquid to obtain dark grey sulfur graphene oxide; (3) adding a potassium iodide solution to the obtained sulfur graphene oxide composite material, and adding diluted hydrochloric acid to obtain a sulfur graphene composite material; and (4) adding the obtained sulfur graphene composite material to N-methylpyrrolidone for stirring, adding 1,5-dichloroanthraquinone for stirring, and then adding anhydrous sodium sulfide to obtain the poly-anthraquinone thioether / graphene / sulphur composite material. The sulphur in the composite material is coated with flexible graphene and poly-anthraquinone thioether, so that dissolution of a discharge product polysulfide can be inhibited; and volume expansion is relieved.

Description

technical field [0001] The invention belongs to the field of nanomaterial synthesis, and relates to a preparation method of a lithium-sulfur battery positive electrode material, in particular to a preparation method of a graphene / polyanthraquinone sulfide / sulfur composite positive electrode material. Background technique [0002] A lithium-sulfur battery is a battery system in which metallic lithium is used as the negative electrode and elemental sulfur is used as the positive electrode. Lithium-sulfur batteries have two discharge platforms (about 2.4V and 2.1V), but their electrochemical reaction mechanism is relatively complicated. Lithium-sulfur batteries have the advantages of high specific energy (2600Wh / kg), high specific capacity (1675mAh / g), and low cost, and are considered to be a promising new generation of batteries. However, at present, there are problems such as low utilization of active materials, low cycle life and poor safety, which seriously restrict the de...

AI Technical Summary

Problems solved by technology

This phenomenon, known as the shuttle effect, reduces the availability of sulfur active species

At the same time insoluble Li 2 S and Li 2 S 2 Deposited on the surface of the lithium negative electrode, which further deteriorates the performance of the lithium-sulfur battery; (3) the final product of the reaction, Li 2 S is also an electronic insulator and will be deposited on the sulfur electrode, while lithium ions migrate slowly in solid lithium sulfide, slowing down the electrochemical reaction kinetics; (4) sulfur and the final product Li 2 The density of S is different. When sulfur is lithiated, the volume expands by about 79%, which easily leads to Li 2 Pulverization of S, causing safety problems in lithium-sulfur batteries

The above deficiencies restrict the development of lithium-sulfur batteries, which is also a key issue that needs to be solved in current research on lithium-sulfur batteries.

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