Lithium-sulfur battery taking zinc sulfide-loaded elemental sulfur with hollow hexagonal rod-like structure as positive electrode material and preparation method thereof

Abstract

The invention relates to the technical field of lithium metal batteries, in particular to a lithium-sulfur battery taking zinc sulfide-loaded elemental sulfur with a hollow hexagonal rod-like structure as a positive electrode material and a preparation method thereof. The positive electrode adopts a zinc sulfide-loaded elemental sulfur structure material with a hexagonal three-dimensional nanorodshell structure. The preparation method comprises the following steps of (1) preparing rod-like zinc oxide, (2) carrying out surface reaction on zinc oxide to convert zinc oxide into zinc sulfide, (3)removing zinc oxide to obtain a zinc sulfide hollow structure, (4) filling sulfur into the zinc sulfide hollow structure, (5) preparing a positive electrode by taking the product as a positive electrode material, and (6) assembling the obtained positive electrode and the negative electrode of the lithium sheet to obtain the lithium-sulfur battery. The problems of low capacity, poor cycle performance and the like in research and application of the existing lithium-sulfur battery are solved, the battery capacity is improved, and the charge-discharge rate performance is improved; the hollow nanorod structure has relatively strong filling and adsorption effects on sulfur, so that the capacity and the cycle performance are excellent.

Description

technical field [0001] The invention relates to the technical field of lithium metal batteries, and aims to obtain a lithium-sulfur battery with high capacity and good cycle performance, and specifically relates to a lithium-sulfur battery with a hollow hexagonal rod-shaped zinc sulfide loaded sulfur element as a positive electrode material and its preparation method. Background technique [0002] At present, energy technology is developing rapidly, especially a series of industries represented by new energy vehicles are also promoting the innovation of energy technology; judging from the current market, lithium batteries occupy a major share, and there are other traditional types of batteries (such as Lead-acid batteries, solar cells, etc.); however, with the upgrading of various electronic devices, especially the development of portable and wearable electronic products, there are challenges to battery capacity and performance. Existing battery technology It has become mor...

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Problems solved by technology

[0007] (1) The sulfur element used as the positive electrode material and the intermediate product polysulfide produced during the reaction process have very poor conductivity, which will cause a certain waste of performance;

[0008] (2) The dissolution of the intermediate product in the electrolyte. The long-chain polysulfide (Li2Sx, 4≤x≤8) is easily dissolved in the ether-based electrolyte solution, which causes a part of the product to fail to deposit in the electrolyte after the reaction is completed. On the positive electrode, it precipitates in the electrolyte, resulting in waste of materials and rapid decline in battery capacity;

[0009] (3) Huge volume change before and after charging and discharging. Sulfur will convert between simple substance and polysulfide during charging and discharging. Due to the difference in density between the two, the volume changes. When the reaction is complete, the volume expansion rate will reach 80. %, a huge change in volume will cause the material to be fragile and cause safety problems;

[0010] (4) Shuttle effect, because the dissolved polysulfide will shuttle between the positive and negative electrodes and continuously reduce and oxidize, resulting in self-discharge phenomenon and loss of active materials

[0013] However, there are still problems such as low capacity and poor cycle performance in the research and application of lithium-sulfur batteries.

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