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CN-122025595-A - Starch-integrated catalyst/linear sulfur integrated water-based zinc-sulfur battery positive electrode material and preparation method thereof

CN122025595ACN 122025595 ACN122025595 ACN 122025595ACN-122025595-A

Abstract

The invention provides a starch-integrated catalyst/linear sulfur integrated water-based zinc-sulfur battery positive electrode material and a preparation method thereof, wherein the method comprises the steps of firstly weighing starch, sulfur and ketjen black, and uniformly mixing to obtain a mixture; and finally, soaking the obtained composite material in a polyiodide aqueous solution until the supernatant becomes colorless, centrifuging and drying to obtain the starch-integrated catalyst/linear sulfur integrated water-based zinc-sulfur battery positive electrode material. According to the invention, based on the chromogenic reaction of starch and iodine, iodine is fixed in a starch double-helix structure through hydrogen bond interaction between iodine and a starch polyhydroxy structure, so that the shuttle effect of polyiodides is inhibited, and the iodine catalyst is effectively enriched on the positive electrode side and the catalytic oxidation capability is maximized. The prepared positive electrode material has the advantages of high specific energy, high multiplying power and high stability, and can meet the application requirements of the future energy storage market.

Inventors

  • ZHU ZHIQIANG
  • YAN ZICHAO
  • ZHANG HUI

Assignees

  • 湖南大学
  • 湖大粤港澳大湾区创新研究院(广州增城)

Dates

Publication Date
20260512
Application Date
20260311

Claims (10)

  1. 1. The preparation method of the starch-integrated catalyst/linear sulfur integrated water-based zinc-sulfur battery positive electrode material is characterized by comprising the following steps of: firstly, weighing starch, sulfur and ketjen black with certain mass, and uniformly mixing to obtain a mixture of the starch, the sulfur and the ketjen black; Calcining the mixture of starch, sulfur and ketjen black in a vacuum environment to obtain a starch/sulfur/ketjen black composite material; And thirdly, soaking the starch/sulfur/ketjen black composite material in a polyiodide aqueous solution until the supernatant is colorless, centrifuging and drying to obtain the starch-integrated catalyst/linear sulfur-integrated water-based zinc-sulfur battery positive electrode material.
  2. 2. The method for preparing the starch-integrated catalyst/linear sulfur-integrated water-based zinc-sulfur battery positive electrode material according to claim 1, wherein in the first step, the mass ratio of sulfur to starch to ketjen black is 12:1.5-4.5:8.5-5.5.
  3. 3. The method for preparing a starch-integrated catalyst/linear sulfur-integrated aqueous zinc-sulfur battery positive electrode material according to claim 1, wherein in the first step, the starch is amylopectin.
  4. 4. The method for preparing the starch-integrated catalyst/linear sulfur-integrated aqueous zinc-sulfur battery positive electrode material according to claim 1, wherein in the first step, the mixing mode is ball milling mixing.
  5. 5. The method for preparing a starch-integrated catalyst/linear sulfur-integrated aqueous zinc-sulfur battery positive electrode material according to claim 4, wherein in the first step, the ball milling rotation speed in the ball milling mixing process is 100rpm-300rpm.
  6. 6. The method for preparing the starch integrated catalyst/linear sulfur integrated water-based zinc-sulfur battery positive electrode material according to claim 1, wherein in the second step, a mixture of starch, sulfur and ketjen black is put into a vacuum quartz glass tube for calcination.
  7. 7. The method for preparing the starch-integrated catalyst/linear sulfur integrated water-based zinc-sulfur battery positive electrode material according to claim 1, wherein in the second step, the calcining temperature is 145-195 ℃, the heating rate is 2-10 ℃ per minute, and the calcining time is 6-24 hours.
  8. 8. The method for preparing the starch-integrated catalyst/linear sulfur-integrated aqueous zinc-sulfur battery cathode material according to claim 1, wherein in the third step, I 2 and KI are dissolved in 100mL of ultrapure water according to a molar ratio of 1:1 to prepare a multi-iodide aqueous solution, and the molar concentration of I 2 and KI is 1mmol/L.
  9. 9. The method for preparing a starch-integrated catalyst/linear sulfur-integrated aqueous zinc-sulfur battery positive electrode material according to claim 1, wherein in the third step, the drying temperature is 30-50 ℃.
  10. 10. A starch-integrated catalyst/linear sulfur-integrated aqueous zinc-sulfur battery positive electrode material, characterized in that it is prepared by the preparation method according to any one of claims 1-9.

Description

Starch-integrated catalyst/linear sulfur integrated water-based zinc-sulfur battery positive electrode material and preparation method thereof Technical Field The invention relates to the technical field of secondary battery electrode materials, in particular to a starch-integrated catalyst/linear sulfur integrated water-based zinc-sulfur battery positive electrode material and a preparation method thereof. Background Aqueous sulfur-based batteries are widely regarded as one of the ideal candidates for large-scale energy storage devices because of their high safety, high theoretical specific capacity (1675 mAh g - 1), and low cost (52 Ah $ - 1). Among them, the aqueous zinc-sulfur battery (AZSBs) employs metallic zinc as a negative electrode that is air-stable and has an oxidation-reduction potential (-0.76V vs. SHE) compatible with an aqueous electrolyte, and has been receiving a great deal of attention from researchers. Unlike the solid-liquid-solid conversion path in an alkali metal-sulfur battery, AZSBs adopts a solid-solid conversion mechanism, so that the problem of dissolution of active substances caused by polysulfide shuttling can be effectively avoided, and a more stable reaction path is provided for a sulfur anode in a water-based electrolyte. However, in practical tests, sulfur anodes based on solid-solid conversion pathways tend to exhibit poor reversibility, mainly due to the high oxidation energy barrier of zinc sulfide (ZnS) and the insulating properties and strong bond energy of the cyclic S 8 molecules, leading to their weak electroreductive activity. At present, the introduction of trace amounts of iodine-based catalysts in electrolytes has been widely regarded as an effective strategy for reducing the high oxidation energy barrier of ZnS. This is because the multi-iodide (I 3-) having oxidizing property can convert the high-energy barrier electrochemical oxidation pathway of ZnS (zns→s+zn 2++2e-) into the low-energy barrier chemical oxidation pathway (zns+i 3-→Zn2++S+3I-). However, conventional I 3- oxidation media tend to exhibit limited oxidation capability for ZnS, making it difficult to achieve a complete ZnS chemical oxidation pathway. In addition, the polyiodides produced in the electrolyte may cause an unavoidable "shuttling effect" and thus accelerate the consumption of the catalyst at the negative electrode. Therefore, how to enhance the oxidizing ability of the iodine catalyst and eliminate its "shuttle effect" has become a major challenge in maximizing the effectiveness of iodine-based catalysts to reduce the ZnS oxidation energy barrier. In order to improve the electroreduction activity of the annular S 8 molecule, researchers design various strategies such as doping of a carbon host and chalcogen element to improve conductivity and interface contact, so that the electroreduction activity of sulfur is improved. Although physical contact does improve the electron/ion transport path and effectively solves the sulfur insulation problem, it should be pointed out that the above strategy has limited effect on promoting the reduction process of the cyclic S 8 molecule, which is basically because the strong bond energy in the cyclic S 8 molecule causes the S-S bond to be difficult to dissociate. Compared with nonpolar cyclic S 8 molecules, polar linear sulfur molecules have longer S-S bonds, so that the binding force between sulfur atoms can be weakened, and the polar interaction between sulfur and metal cations can be enhanced, and therefore, the linear sulfur tends to show higher reactivity than the cyclic S 8 molecules. However, free chain sulfur molecules are thermodynamically unstable, which often require physical confinement space to be linked to the polymer backbone or to provide a size match to the microporous carbon matrix, which also results in limited material selection and causes problems with low active loading (< 30%). More notably, the linear sulfur anodes that have been reported generally exhibit greater polarization (0.75V) such that their energy density is still at a low level. In view of the above, it is still difficult to fully exploit the application potential of the sulfur anode by optimizing the oxidation or reduction process alone. Therefore, how to simultaneously enhance the catalytic oxidation capacity of the iodine-based catalyst and the electroreduction activity of sulfur is a key to improving the redox kinetics of sulfur. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a starch-integrated catalyst/linear sulfur integrated water-based zinc-sulfur battery positive electrode material and a preparation method thereof, and aims to improve the catalytic oxidation capacity of an iodine catalyst and the electroreduction activity of sulfur at the same time so as to reduce the oxidation-reduction energy barrier of sulfur and improve the sulfur conversion kinetics. In order to achieve the above purpose, the i