Preparation method of low-cost positive electrode material for aqueous zinc-sulfur battery

Abstract

The application discloses a preparation method of a low-cost positive electrode material of a water-based zinc-sulfur battery, and specifically comprises the following steps: in step 1, coal tar pitch powder and potassium carbonate are weighed according to a mass ratio of 1:1-3, and the two are fully ground and mixed at room temperature; in step 2, the product obtained in step 1 is subjected to first calcination, and after the reaction is completed, the product is naturally cooled to room temperature; in step 3, the product obtained in step 2 is soaked in hydrochloric acid and then centrifuged and washed until the filtrate is neutral, and finally dried; in step 4, the product obtained in step 3 is subjected to second calcination; in step 5, the product obtained in step 3 and industrial sulfur powder are uniformly mixed, and the mass percentage of the industrial sulfur powder is 40%-85%, and then the mixture is subjected to reaction in a high-pressure reaction kettle under nitrogen protection; and in step 6, the product obtained in step 5 is subjected to third calcination.

Description

Technical Field

[0001] This invention belongs to the field of secondary battery electrode material preparation technology, specifically relating to a low-cost method for preparing a positive electrode material for aqueous zinc-sulfur batteries. Background Technology

[0002] To achieve the national strategic goals of "peak carbon emissions by 2030 and carbon neutrality by 2060," the clean and efficient utilization of fossil fuels and their waste has become an urgent priority. Rechargeable batteries, with their high energy density, low production cost, and clean and environmentally friendly characteristics, have attracted significant attention from researchers for large-scale energy storage applications.

[0003] Currently, lithium-ion batteries have become one of the most widely used energy storage devices due to their high energy density, long service life, and high energy efficiency. However, the flammable and explosive organic electrolytes, as well as the limited lithium reserves and high prices, have seriously hindered the development and application of lithium-ion batteries in the field of large-scale energy storage. Therefore, aqueous batteries with high safety and low cost have gradually gained favor among researchers. Among the aqueous batteries reported so far, zinc batteries have shown strong competitiveness, with the following main advantages: (1) Zinc metal has abundant resources, high chemical stability, suitable redox potential (-0.763V), and high theoretical capacity (820mAh g). -1 5855mAh cm -3 (2) The electrolyte is an aqueous solution, which has the characteristics of low cost, safety, high ionic conductivity and environmental friendliness.

[0004] Currently, the widely reported zinc battery cathode materials, such as manganese-based materials, vanadium-based materials, Prussian blue materials, and organic materials, generally offer a specific capacity of no more than 400 mAh g. -1 Compared to the materials mentioned above, sulfur electrodes, as a conversion-type cathode material, have a lower cost (0.25 US dollars per kg). -1 ) and a higher theoretical specific capacity (1675mAh g) -1 However, sulfur has poor conductivity, and direct solid-solid conversion of the sulfur cathode in an aqueous electrolyte leads to sluggish kinetics, hindering the conversion reaction. Therefore, finding suitable sulfur cathode host materials is crucial for the development of aqueous zinc-sulfur batteries for practical applications. Among them, coal tar pitch-based carbon materials, with abundant resources, low production costs, high conductivity, and suitable pore structure, have long been regarded as the most promising energy storage electrode materials, but their application in aqueous zinc-sulfur batteries is still in its early stages. Summary of the Invention

[0005] The purpose of this invention is to provide a low-cost method for preparing aqueous zinc-sulfur battery cathode materials, utilizing coal tar pitch-based carbon materials to prepare aqueous zinc-sulfur battery cathode materials.

[0006] To address the aforementioned technical problems, this invention discloses a low-cost method for preparing an aqueous zinc-sulfur battery cathode material, specifically implemented according to the following steps:

[0007] Step 1: Weigh coal tar pitch powder and potassium carbonate in a mass ratio of 1:1-3, and grind and mix them thoroughly at room temperature.

[0008] Step 2: The product obtained in Step 1 is calcined for the first time. After the reaction is complete, it is allowed to cool naturally to room temperature.

[0009] Step 3: Soak the product obtained in Step 2 in hydrochloric acid and let it stand, then centrifuge and wash until the filtrate is neutral, and finally dry it.

[0010] Step 4: The product obtained in Step 3 is subjected to a second calcination;

[0011] Step 5: Mix the product obtained in the previous step with industrial sulfur powder evenly, with the industrial sulfur powder accounting for 40%-85% by mass. Then, react the mixture in a high-pressure reactor under nitrogen protection.

[0012] Step 6: The product obtained in step 5 is subjected to a third calcination.

[0013] The technical solution of the present invention also has the following characteristics:

[0014] As a further improvement to the technical solution of the present invention, in step 2, the first calcination is carried out in a tube furnace under argon protection at 600℃-800℃ for 0.5h-1.5h, with a heating rate of 2℃ / min-10℃ / min.

[0015] As a further improvement to the technical solution of the present invention, in step 3, the concentration of hydrochloric acid is 0.1mol / L-0.5mol / L.

[0016] As a further improvement to the technical solution of the present invention, in step 3, the standing time is 18h-36h.

[0017] As a further improvement to the technical solution of the present invention, in step 3, the drying temperature is 75℃-85℃ and the time is 10h-20h.

[0018] As a further improvement to the technical solution of the present invention, in step 4, the second calcination is carried out in a tube furnace under argon protection at 950℃-1050℃ for 0.5h-2.5h, with a heating rate of 2℃ / min-10℃ / min.

[0019] As a further improvement to the technical solution of the present invention, in step 5, the mixture is reacted in a high-pressure reactor under nitrogen protection at a temperature of 150℃-165℃ for a time of 12h-15h.

[0020] As a further improvement to the technical solution of the present invention, in step 6, the third calcination is: reacting in a tube furnace at 190℃-210℃ for 20min-50min under argon protection, with a heating rate of 2℃ / min-5℃ / min.

[0021] Compared with existing technologies, this invention provides a low-cost method for preparing aqueous zinc-sulfur battery cathode materials. Through high-temperature calcination and melt diffusion, an amorphous carbon-supported industrial sulfur powder cathode material with a mesoporous structure derived from coal tar pitch is synthesized. A series of characterization methods confirm the successful preparation of this material, and electrochemical testing demonstrates its excellent cycle stability and rate performance when applied to aqueous zinc-sulfur batteries. This also broadens the scope of coal tar pitch in the preparation and application of electrode materials for secondary batteries. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 a and Figure 1 b are N2 adsorption-desorption isotherms of coal tar pitch raw material (CTP) and amorphous carbon material (CPC) after high-temperature calcination in Example 1 of this invention.

[0024] Figure 2 a is a SEM image of CPC in Embodiment 1 of the present invention. Figure 2 bg is a TEM image of CPC in Embodiment 1 of the present invention.

[0025] Figure 3 a and Figure 3 b are the XRD patterns of CPC and CPC loaded with different contents of sulfur powder (CPC / S-60.33%, CPC / S-68.35%, CPC / S-76.40%) in Examples 1, 2, and 3 of the present invention.

[0026] Figure 4 a is the thermogravimetric curve of CPC / S-60.33% in Example 1 of the present invention.

[0027] Figure 4 b is the thermogravimetric curve of CPC / S-68.35% in Example 2 of the present invention.

[0028] Figure 4c is the thermogravimetric curve of CPC / S-76.40% in Example 3 of the present invention.

[0029] Figure 5 The XPS spectra of CPC and CPC / S-60.33% in Embodiment 1 of the present invention are shown.

[0030] Figure 6 This is a cycle performance graph of CPC / S-60.33%, CPC / S-68.35%, and CPC / S-76.40% for Embodiments 1, 2, and 3 of the present invention.

[0031] Figure 7 a is a cycle performance graph of CPC / S-60.33% for Embodiment 1 of the present invention.

[0032] Figure 7 b is the cycle performance graph of CPC / S-68.35% in Embodiment 2 of the present invention.

[0033] Figure 7 c is the cycle performance graph of CPC / S-76.40% in Embodiment 3 of the present invention. Detailed Implementation

[0034] Example 1

[0035] The present invention discloses a low-cost method for preparing an aqueous zinc-sulfur battery cathode material, which is implemented according to the following steps:

[0036] Step 1: Weigh coal tar pitch powder and potassium carbonate in a 1:1 mass ratio, and grind and mix them thoroughly at room temperature.

[0037] Step 2: The product obtained in Step 1 is subjected to a first calcination. After the reaction is complete, it is naturally cooled to room temperature. The first calcination is carried out in a tube furnace at 600℃ for 1.5h under argon protection, with a heating rate of 2℃ / min.

[0038] Step 3: Soak the product obtained in Step 2 in 0.1 mol / L hydrochloric acid and let it stand for 18 hours. Then centrifuge and wash until the filtrate is neutral. Finally, dry it at 75°C for 20 hours.

[0039] Step 4: The product obtained in Step 3 is subjected to a second calcination. The second calcination is carried out in a tube furnace under argon protection at 950℃ for 2.5h, with a heating rate of 2℃ / min.

[0040] Step 5: Mix the product obtained in the step with industrial sulfur powder evenly, with the industrial sulfur powder accounting for 40% by mass. Then, react the mixture in a high-pressure reactor at 150°C for 15 hours under nitrogen protection.

[0041] Step 6: The product obtained in step 5 is subjected to a third calcination. The third calcination is carried out in a tube furnace under argon protection at 190°C for 50 min, with a heating rate of 2°C / min.

[0042] Example 2

[0043] The present invention discloses a low-cost method for preparing an aqueous zinc-sulfur battery cathode material, which is implemented according to the following steps:

[0044] Step 1: Weigh coal tar pitch powder and potassium carbonate in a mass ratio of 1:2, and grind and mix them thoroughly at room temperature.

[0045] Step 2: The product obtained in Step 1 is subjected to a first calcination. After the reaction is complete, it is naturally cooled to room temperature. The first calcination is carried out in a tube furnace at 700℃ for 1 hour under argon protection, with a heating rate of 6℃ / min.

[0046] Step 3: Soak the product obtained in Step 2 in 0.3 mol / L hydrochloric acid and let it stand for 27 h. Then centrifuge and wash until the filtrate is neutral. Finally, dry it at 80 °C for 15 h.

[0047] Step 4: The product obtained in Step 3 is subjected to a second calcination. The second calcination is carried out in a tube furnace under argon protection at 1000℃ for 1.5h, with a heating rate of 6℃ / min.

[0048] Step 5: Mix the product obtained in the step with industrial sulfur powder evenly, with the industrial sulfur powder accounting for 62% by mass. Then, react the mixture in a high-pressure reactor at 157°C for 13 hours under nitrogen protection.

[0049] Step 6: The product obtained in step 5 is subjected to a third calcination. The third calcination is carried out in a tube furnace under argon protection at 200°C for 35 min, with a heating rate of 3°C / min.

[0050] Example 3

[0051] The present invention discloses a low-cost method for preparing an aqueous zinc-sulfur battery cathode material, which is implemented according to the following steps:

[0052] Step 1: Weigh coal tar pitch powder and potassium carbonate in a mass ratio of 1:3, and grind and mix them thoroughly at room temperature.

[0053] Step 2: The product obtained in Step 1 is subjected to a first calcination. After the reaction is complete, it is naturally cooled to room temperature. The first calcination is carried out in a tube furnace at 800℃ for 0.5h under argon protection, with a heating rate of 10℃ / min.

[0054] Step 3: Soak the product obtained in Step 2 in 0.5 mol / L hydrochloric acid and let it stand for 36 h. Then centrifuge and wash until the filtrate is neutral. Finally, dry it at 85 °C for 10 h.

[0055] Step 4: The product obtained in Step 3 is subjected to a second calcination. The second calcination is carried out in a tube furnace under argon protection at 1050℃ for 0.5h, with a heating rate of 10℃ / min.

[0056] Step 5: Mix the product obtained in the step with industrial sulfur powder evenly, with the industrial sulfur powder accounting for 85% by mass. Then, react the mixture in a high-pressure reactor at 165°C for 12 hours under nitrogen protection.

[0057] Step 6: The product obtained in step 5 is subjected to a third calcination. The third calcination is carried out in a tube furnace under argon protection at 210°C for 20 min, with a heating rate of 5°C / min.

[0058] Figure 1 The figures show the nitrogen adsorption-desorption isotherms for CTP and CPC. The CTP feedstock exhibits an open curve with an almost zero specific surface area and no porous structure. After activation with potassium carbonate and high-temperature calcination, the specific surface area of ​​CTP reaches as high as 682 m². 2 / g, with abundant mesoporous structure and an average pore size of less than 5nm.

[0059] Figure 2 a is the SEM image of CPC. Figure 2 Figure bg is a TEM image of CPC. Figures a and b show the abundant porous structure of the CPC. Figure c indicates that the prepared CPC is amorphous carbon, which is further verified by selected area electron diffraction. Figure dg is the mapping pattern of CPC, showing uniform distribution of C and O elements, further confirming the successful preparation of CPC.

[0060] Figure 3 a is the XRD pattern of CPC. Figure 3 b is the XRD pattern of CPC / S-60.33%, CPC / S-68.35%, and CPC / S-76.40%. Figure 3 a exhibits two broad diffraction peaks near 22° and 43°, corresponding to the (002) and (100) planes in the amorphous carbon structure. After CPC loading with sulfur, Figure 3 The XRD pattern of b showed a characteristic peak of S, indicating the successful preparation of CPC sulfur-loaded material.

[0061] Figure 4a, b, and c are thermogravimetric curves for CPC / S of -60.33%, -68.35%, and -76.40%, respectively. The mass fraction of sulfur loading can be quantitatively determined from the weight loss portion of the thermogravimetric curves.

[0062] Figure 5 These are the XPS spectra of CPC and CPC / S-60.33%. The CPC spectrum only shows the presence of C1s and O1s peaks, indicating that the prepared CPC is free of impurities. After loading sulfur, S 2s and S 2p peaks also appear, indicating the successful preparation of the sulfur-loaded CPC material.

[0063] Figure 6 This chart shows the rate performance of CPC / S-60.33%, CPC / S-68.35%, and CPC / S-76.40% at different current densities. At all tested current densities, the CPC / S-60.33% electrode material exhibits a higher specific capacity than both CPC / S-68.35% and CPC / S-76.40%.

[0064] Figure 7 a, b, and c represent CPC / S values ​​of -60.33%, -68.35%, and -76.40% respectively at a current density of 5 A g. -1 The following is a graph showing the cycling performance. CPC / S - 60.33% initial capacity up to 260mAh g. -1 The results showed that CPC was a good sulfur host material, and it could cycle stably for 400 cycles under all three sulfur loading levels.

[0065] Based on this, the present invention synthesizes amorphous carbon-supported industrial sulfur powder cathode material with mesoporous structure derived from coal tar pitch through high-temperature calcination and melt diffusion method. Electrochemical tests have demonstrated that its application in aqueous zinc-sulfur batteries can exhibit excellent cycle stability and rate performance.

Claims

1. A method for preparing a low-cost aqueous zinc-sulfur battery cathode material, characterized in that, The specific steps are as follows: Step 1: Weigh coal tar pitch powder and potassium carbonate in a mass ratio of 1:1-3, and grind and mix them thoroughly at room temperature. Step 2: The product obtained in Step 1 is calcined for the first time. After the reaction is complete, it is allowed to cool naturally to room temperature. Step 3: Soak the product obtained in Step 2 in hydrochloric acid and let it stand, then centrifuge and wash until the filtrate is neutral, and finally dry it. Step 4: The product obtained in Step 3 is subjected to a second calcination; Step 5: Mix the product obtained in Step 4 with industrial sulfur powder evenly, with the industrial sulfur powder accounting for 40%-85% by mass. Then, react the mixture in a high-pressure reactor under nitrogen protection. Step 6: Calcine the product obtained in Step 5 for the third time; In step 2, the first calcination is carried out in a tube furnace under argon protection at 600℃-800℃ for 0.5h-1.5h, with a heating rate of 2℃ / min-10℃ / min. In step 3, the concentration of hydrochloric acid is 0.1 mol / L to 0.5 mol / L; In step 4, the second calcination is carried out in a tube furnace under argon protection at 950℃-1050℃ for 0.5h-2.5h, with a heating rate of 2℃ / min-10℃ / min. In step 5, the mixture is reacted in a high-pressure reactor under nitrogen protection at a temperature of 150℃-165℃ for 12h-15h. In step 6, the third calcination is carried out in a tube furnace under argon protection at 190℃-210℃ for 20min-50min, with a heating rate of 2℃ / min-5℃ / min.

2. The method for preparing the low-cost aqueous zinc-sulfur battery cathode material according to claim 1, characterized in that, In step 3, the settling time is 18h-36h.

3. The method for preparing the low-cost aqueous zinc-sulfur battery cathode material according to claim 2, characterized in that, In step 3, the drying temperature is 75℃-85℃ and the drying time is 10h-20h.

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