Preparation method of poly-o-phenylenediamine intercalated mnO2 positive electrode material and application thereof in aqueous zinc ion battery

Abstract

The application belongs to the technical field of materials, and particularly relates to a preparation method of a PoPD-MnO2 positive electrode material and application of the PoPD-MnO2 positive electrode material in a water-based zinc ion battery. The preparation method is as follows: potassium permanganate and o-phenylenediamine are dissolved in deionized water, stirring is performed at room temperature, the well-mixed solution is transferred into a hydrothermal reaction kettle, hydrothermal reaction is performed, cooling is performed to room temperature, centrifugal cleaning is performed, vacuum drying is performed, and the PoPD-MnO2 positive electrode material is obtained. In the application, ammonium ions are inserted into the electrode material, the layer spacing of the ammonium ions inserted into the MnO2 is enlarged, the active sites are increased, the diffusion and charge transfer of ions are effectively promoted, the conductivity of the material is improved, the internal resistance is reduced, the structural flexibility and stability of the material are maintained, and thus the overall performance of the water-based zinc ion battery is improved.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, specifically relating to a method for preparing a PoPD-MnO2 cathode material and its application in aqueous zinc-ion batteries. Background Technology

[0002] With the rapid development of renewable energy sources such as solar, biomass, hydropower, and wind power, as well as the construction of smart grids, the development of microgrid technology, and energy interconnection, energy storage technology presents a new challenge that will reshape the global energy landscape. Electrochemical energy storage has received significant attention due to its application flexibility, high conversion efficiency, and high power density, and is considered an important form of energy storage for the future. Over the past decade, lithium-ion batteries have garnered widespread attention due to their high energy density and long cycle life. However, the limited availability of lithium resources, development difficulties, and potential safety issues associated with the use of high-cost organic electrolytes have constrained the further development of lithium-ion batteries, resulting in a still relatively high cost for commercial lithium-ion batteries. In contrast, zinc reserves in the Earth's crust are relatively abundant, approximately 3.5 times that of lithium, and mining technology is more mature. Therefore, in electrochemical energy storage systems outside of lithium-ion batteries, aqueous zinc-ion batteries (AZIBs) have a high theoretical capacity (820 mAh·g). -1 The advantages of zinc anodes, such as suitable redox potential, high zinc abundance, and non-toxic aqueous electrolytes, make them a promising direction for battery research. In particular, the aqueous electrolytes used can provide higher ionic conductivity than organic electrolytes, thus achieving superior rate performance and better safety. Currently, many cathode materials have been applied to AZIBs, such as manganese oxides, vanadium oxides, and Prussian blue analogues. However, Zn... 2+ The high charge-to-ionic radius ratio and strong Coulomb interaction of Zn lead to its slow diffusion in the lattice of these electrode materials, and Zn 2+ Repeated insertion may cause collapse and dissolution of the cathode material, thereby reducing its electrochemical performance. Summary of the Invention

[0003] To address the above problems, this invention provides a method for preparing PoPD-MnO2 cathode material and its application in aqueous zinc-ion batteries.

[0004] The technical solution adopted in this invention is: a poly(o-phenylenediamine) intercalated MnO2 cathode material, PoPD-MnO2, the preparation method of which includes the following steps:

[0005] A certain amount of potassium permanganate and o-phenylenediamine are dissolved in deionized water, and stirred at room temperature to mix thoroughly, and the mixed solution is transferred into a polytetrafluoroethylene-lined stainless steel hydrothermal reactor for hydrothermal reaction, cooled to room temperature, centrifuged to remove residual reactants, and vacuum dried to obtain the PoPD-MnO2 positive electrode material.

[0006] The PoPD-MnO2 positive electrode material is prepared by mixing potassium permanganate and o-phenylenediamine in a molar ratio of 4:0.15-0.25.

[0007] The PoPD-MnO2 positive electrode material is prepared by adjusting the pH of the mixed solution to 4.

[0008] The PoPD-MnO2 positive electrode material is prepared by hydrothermal reaction at 200℃ for 24h.

[0009] The PoPD-MnO2 positive electrode material is used in a water-based zinc ion battery.

[0010] The method comprises the following steps:

[0011] 1) Preparation of the positive electrode: the PoPD-MnO2 positive electrode material is mixed with a binder and a conductive material, a small amount of NMP is added as a solvent, and the mixture is uniformly coated on a carbon paper substrate, and then dried in a vacuum drying oven to obtain a positive electrode sheet coated with the PoPD-MnO2 material.

[0012] 2) Preparation of the negative electrode: a zinc sheet with a thickness of 0.1mm-0.2mm and a purity of 99%-99.99% is polished with sandpaper to remove the surface oxide layer, and the polished zinc sheet is cut into a circular negative electrode sheet with a diameter of 12mm.

[0013] 3) The positive electrode sheet prepared in step 1) is used as the positive electrode, the negative electrode sheet prepared in step 2) is used as the negative electrode, and the electrolyte is 2M zinc trifluoromethanesulfonate + 0.1M manganese sulfate to obtain a water-based zinc ion battery.

[0014] In step 1) of the application, the binder is PVDF.

[0015] In step 1) of the application, the conductive material is Super-p.

[0016] The application has the following advantages:

[0017] 1. By introducing ammonium ions during synthesis, the conductivity, ion diffusion rate, and internal resistance of the material are significantly improved.

[0018] 2、The introduction of ammonium ions expands the interlayer spacing of MnO2, changes the charge distribution, and improves the Zn 2+ The migration rate in the hybrid material, thereby improving the specific capacity and rate performance of the material in the charging and discharging process.

[0019] 3、The ammonium ion serves as a support in the interlayer, improving the stability of the material.

[0020] 4、It has the characteristics of low cost, environmental friendliness, and high safety.

[0021] 5、It has the advantages of high energy density and power density.

[0022] 6、The synthesis process and assembly process are simple, easy to operate and control, and suitable for continuous large-scale production.

[0023] 7、After modification, the capacity of the positive electrode material is increased from 53mAh / g to 93mAh / g.

[0024] 8、The method is also applicable to other metal oxide positive electrode materials. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the XRD spectrum of MnO2 and PoPD-MnO2 prepared in Example 1.

[0026] Figure 2 is the cyclic voltammogram of MnO2 and PoPD-MnO2 prepared in Example 1.

[0027] Figure 3 is the SEM spectrum of MnO2 and PoPD-MnO2 prepared in Example 1.

[0028] Figure 4 is the specific capacity graph of MnO2 and PoPD-MnO2 prepared in Example 1. DETAILED DESCRIPTION

[0029] The technical solutions of the present application are further described below, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present application without departing from the spirit and scope of the technical solutions of the present application shall be covered in the protection scope of the present application.

[0030] Preparation of MnO2 and PoPD-MnO2 in Example 1

[0031] The preparation method of MnO2 is as follows:

[0032] Take 632 mg of potassium permanganate powder, dissolve it in deionized water, stir at room temperature to mix thoroughly, transfer the thoroughly mixed solution to a polytetrafluoroethylene-lined stainless steel hydrothermal reactor, hydrothermal reaction at 200 ℃ for 24 h, cool to room temperature, centrifugal washing to remove residual reactants, vacuum drying, to obtain MnO2 positive electrode material.

[0033] (II) Preparation method of PoPD-MnO2 as follows:

[0034] Take 632 mg of potassium permanganate and 21.6 mg of o-phenylenediamine, dissolve it in deionized water, stir at room temperature, add HCl to adjust the PH of the solution to 4, continue to stir until mixed thoroughly, transfer the thoroughly mixed solution to a polytetrafluoroethylene-lined stainless steel hydrothermal reactor, hydrothermal reaction at 200 ℃ for 24 h, cool to room temperature, centrifugal washing to remove residual reactants, vacuum drying, to obtain PoPD-MnO2 positive electrode material.

[0035] (III) Detection

[0036] Figure 1 is the XRD spectrum of MnO2 and PoPD-MnO2 prepared in this example. From Figure 1 It can be seen that after PoPD intercalation, the XRD spectrum of the sample does not show obvious change, the shift of individual peaks and the increase of peak width indicate that ammonium ions have been successfully inserted into the layered MnO2. Figure 2 is the cyclic voltammogram of MnO2 and PoPD-MnO2. From Figure 2 It can be seen that the area enclosed by PoPD-MnO2 is significantly larger than that of pure MnO2, which indicates that the capacity of PoPD-MnO2 is greater than that of pure MnO2. Figure 3 is the SEM spectrum of PoPD-MnO2. From Figure 3 It can be seen that the prepared PoPD-MnO2 is a typical nanoflower structure. Figure 4 is the specific capacity of MnO2 and PoPD-MnO2. From Figure 4 It can be seen that the specific capacity and cycle stability of PoPD-MnO2 are much higher than those of pure MnO2.

[0037] Example 2 Preparation of PoPD-MnO2

[0038] Take 632 mg of potassium permanganate and 21.6 mg of o-phenylenediamine, dissolve it in deionized water, stir at room temperature, add HCl to adjust the PH of the solution to 4, continue to stir until mixed thoroughly, transfer the thoroughly mixed solution to a polytetrafluoroethylene-lined stainless steel hydrothermal reactor, hydrothermal reaction at 200 ℃ for 24 h, cool to room temperature, centrifugal washing to remove residual reactants, vacuum drying, to obtain PoPD-MnO2 positive electrode material.

[0039] Preparation of PoPD-MnO2

[0040] Take 632 mg of potassium permanganate and 27 mg of o-phenylenediamine, dissolve them in deionized water, stir at room temperature, add HCl to adjust the PH of the solution to 4, continue to stir until fully mixed, transfer the fully mixed solution to a polytetrafluoroethylene lined stainless steel hydrothermal reactor, hydrothermal reaction at 200°C for 24h, cool to room temperature, centrifugal washing to remove residual reactants, vacuum drying, to obtain PoPD-MnO2 positive electrode material.

[0041] Preparation of negative electrode material

[0042] The zinc sheet with a thickness of 0.1 mm and a purity of 99.99% is repeatedly polished with sandpaper to remove the surface oxide layer, and the polished zinc sheet is cut into a circular negative electrode sheet with a diameter of 12 mm for standby.

[0043] Preparation of negative electrode material

[0044] The zinc sheet with a thickness of 0.2 mm and a purity of 99.99% is repeatedly polished with sandpaper to remove the surface oxide layer, and the polished zinc sheet is cut into a circular negative electrode sheet with a diameter of 12 mm for standby.

[0045] Preparation of aqueous zinc ion battery

[0046] 1) Preparation of positive electrode: the PoPD-MnO2 positive electrode material prepared in Example 1 is mixed with PVDF and Super-p in a mass ratio of 8:1:1, a small amount of NMP is added as a solvent, and the mixture is mixed uniformly, then directly coated on the substrate carbon paper, vacuum dried, and taken out to obtain a positive electrode sheet coated with PoPD-MnO2 material;

[0047] 2) The positive electrode prepared in step 1) is used as the positive electrode, the negative electrode prepared in Example 4 is used as the negative electrode, and the electrolyte is selected as 2M zinc trifluoromethanesulfonate + 0.1M manganese sulfate to obtain an aqueous zinc ion battery and perform electrochemical test.

[0048] Preparation of aqueous zinc ion battery

[0049] 1) Preparation of positive electrode: the PoPD-MnO2 positive electrode material prepared in Example 2 is mixed with PVDF and Super-p in a mass ratio of 8:1:1, a small amount of NMP is added as a solvent, and the mixture is mixed uniformly, then directly coated on the substrate carbon paper, vacuum dried, and taken out to obtain a positive electrode sheet coated with PoPD-MnO2 material;

[0050] 2) The positive electrode prepared in step 1) is used as the positive electrode, the negative electrode prepared in Example 4 is used as the negative electrode, and the electrolyte is selected as 2M zinc trifluoromethanesulfonate + 0.1M manganese sulfate, to obtain a water-based zinc ion battery and perform electrochemical testing.

[0051] Example 8 Preparation of a water-based zinc ion battery

[0052] 1) Preparation of the positive electrode: the PoPD-MnO2 positive electrode material prepared in Example 3 is mixed with PVDF and Super-p at a mass ratio of 8:1:1, a small amount of NMP is added as a solvent, and the mixture is mixed uniformly, then directly applied to the substrate carbon paper, and dried in a vacuum drying oven, and then taken out to obtain a positive electrode sheet coated with PoPD-MnO2 material;

[0053] 2) The positive electrode prepared in step 1) is used as the positive electrode, the negative electrode prepared in Example 4 is used as the negative electrode, and the electrolyte is selected as 2M zinc trifluoromethanesulfonate + 0.1M manganese sulfate, to obtain a water-based zinc ion battery and perform electrochemical testing.

[0054] Example 9 Preparation of a water-based zinc ion battery

[0055] 1) Preparation of the positive electrode: the PoPD-MnO2 positive electrode material prepared in Example 1 is mixed with PVDF and Super-p at a mass ratio of 8:1:1, a small amount of NMP is added as a solvent, and the mixture is mixed uniformly, then directly applied to the substrate carbon paper, and dried in a vacuum drying oven, and then taken out to obtain a positive electrode sheet coated with PoPD-MnO2 material;

[0056] 2) The positive electrode prepared in step 1) is used as the positive electrode, the negative electrode prepared in Example 5 is used as the negative electrode, and the electrolyte is selected as 2M zinc trifluoromethanesulfonate + 0.1M manganese sulfate, to obtain a water-based zinc ion battery and perform electrochemical testing.

[0057] Example 10 Preparation of a water-based zinc ion battery

[0058] 1) Preparation of the positive electrode: the PoPD-MnO2 positive electrode material prepared in Example 2 is mixed with PVDF and Super-p at a mass ratio of 8:1:1, a small amount of NMP is added as a solvent, and the mixture is mixed uniformly, then directly applied to the substrate carbon paper, and dried in a vacuum drying oven, and then taken out to obtain a positive electrode sheet coated with PoPD-MnO2 material;

[0059] 2) The positive electrode prepared in step 1) is used as the positive electrode, the negative electrode prepared in Example 5 is used as the negative electrode, and the electrolyte is selected as 2M zinc trifluoromethanesulfonate + 0.1M manganese sulfate, to obtain a water-based zinc ion battery and perform electrochemical testing.

[0060] Example 11 Preparation of a water-based zinc ion battery

[0061] 1) Preparation of the positive electrode: the PoPD-MnO2 positive electrode material prepared in Example 3 was mixed with PVDF and Super-p in a mass ratio of 8:1:1, and then a small amount of NMP was added as a solvent. After mixing, the mixture was directly coated on a carbon paper substrate, and then dried in a vacuum drying oven. The positive electrode sheet coated with the PoPD-MnO2 material was obtained;

[0062] 2) The positive electrode sheet prepared in step 1) was used as the positive electrode, and the negative electrode sheet prepared in Example 5 was used as the negative electrode. The electrolyte was 2M zinc trifluoromethanesulfonate + 0.1M manganese sulfate. A water-based zinc ion battery was obtained and subjected to electrochemical testing.

[0063] Among the six water-based zinc ion batteries assembled according to Examples 6-11, the electrochemical performance of Example 6 was the best. When the current density was 3 A·g -1 Figure 4 When the molar ratio of potassium permanganate to o-phenylenediamine was 4:0.2 in Example 6, the PoPD-MnO2 formed in comparison to pure MnO2 expanded its interlayer spacing to provide more active sites, which was more conducive to the insertion and extraction of zinc ions, thereby improving the electrochemical performance.​

Claims

1. Application of a poly-o-phenylenediamine intercalated MnO2 cathode material PoPD-MnO2 in aqueous zinc ion batteries, characterized in that, The preparation method of the poly-o-phenylenediamine intercalated MnO2 cathode material PoPD-MnO2 comprises the following steps: Potassium permanganate and o-phenylenediamine are weighed according to a molar ratio of 4:0.15-0.25, dissolved in deionized water, and stirred at room temperature to mix thoroughly, and the PH of the mixed solution is adjusted to 4; the mixed solution is transferred into a polytetrafluoroethylene-lined stainless steel hydrothermal reactor, and hydrothermal reaction is carried out; the solution is cooled to room temperature, centrifuged to remove residual reactants, and vacuum dried to obtain the PoPD-MnO2 cathode material.

2. Use according to claim 1, characterized in that, The hydrothermal reaction condition is 200℃ for 24h.

3. Use according to claim 1, characterized in that, The method comprises the following steps: 1) Preparation of the cathode: the PoPD-MnO2 cathode material is mixed with a binder and a conductive material, a small amount of NMP is added as a solvent, and the mixture is uniformly coated on a carbon paper substrate, and then dried in a vacuum drying oven, and the coated PoPD-MnO2 material is obtained; 2) Preparation of the anode: a zinc sheet with a thickness of 0.1mm-0.2mm and a purity of 99%-99.99% is polished with sandpaper to remove the surface oxide layer, and the polished zinc sheet is cut into a circular anode sheet with a diameter of 12mm; 3) The cathode prepared in step 1) is used as the positive electrode, the anode prepared in step 2) is used as the negative electrode, and the electrolyte is 2M zinc trifluoromethanesulfonate+0.1M manganese sulfate to obtain a water-based zinc ion battery.

4. Use according to claim 3, characterized in that, In step 1), the binder is PVDF.

5. Use according to claim 3, characterized in that, In step 1), the conductive material is Super-p.

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