Polypyrrole-doped PPy-Na2V6O16. 3H2O electrode material, preparation method thereof and application of polypyrrole-doped PPy-Na2V6O16. 3H2O electrode material in aqueous zinc ion battery

Abstract

The invention provides a polypyrrole (PPy) doped PPy-Na2V6O16. 3H2O electrode material as well as a preparation method and application thereof in an aqueous zinc ion battery. The preparation method comprises the following steps: adding V2O5, H2O2 and NaOH into deionized water, adding PPy into an obtained mixed solution, and continuously stirring; and transferring the obtained mixed solution into a stainless steel hydrothermal reaction kettle with a polytetrafluoroethylene lining, carrying out hydrothermal reaction, cooling to room temperature, carrying out centrifugal cleaning, and carrying out vacuum drying to obtain the PPy-doped PVP-Na2V6O16. 3H2O nanorod. According to the invention, the PPy is doped in the electrode material, and the conductive organic polymer is inserted into Na2V6O16. 3H2O, so that the interlayer spacing is effectively expanded, the embedding efficiency and energy storage capacity of zinc ions are further improved, the internal resistance is reduced, the coulomb effect is shielded, the transmission channel of the zinc ions is expanded, and the overall performance of the aqueous zinc ion battery is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials, and particularly relates to a PPy-Na doped with polypyrrole 2 V 6 O 16 ·3H 2 O electrode material, its preparation method and application in aqueous zinc ion batteries Background Art

[0002] In recent years, the global warming problem and the deterioration of the ecological environment caused by non-renewable energy have received increasing attention. In order to overcome the shortage of traditional fossil fuels and alleviate the environmental crisis, it is urgent to develop and utilize renewable clean energy (such as solar energy, geothermal energy, wind energy, etc.). The transportation and storage of renewable clean energy are the keys to its efficient utilization. Energy storage devices that convert chemical energy into electrical energy are relatively mature, and effective methods for storing intermittent clean energy can achieve large-scale energy transmission. Therefore, the development of sustainable and renewable energy storage devices is an effective way to address issues such as energy crisis and climate change, and it has one of the most decisive impacts on future technology fields and the future global economy. As a key step in developing such technologies, it is necessary to advance energy storage devices, such as high-energy density batteries for storing green energy

[0003] Currently, lithium-ion batteries dominate the portable electronics market due to their high energy density and long life. However, concerns about safety, cost, especially the limited supply of lithium, have hindered their long-term layout in the field of large-scale energy storage. Based on this, aqueous rechargeable batteries are considered a promising alternative for the next generation of electrochemical energy storage due to their low cost, high operational safety, and environmental friendliness. Among them, the ionic conductivity of the aqueous electrolyte (1 S / cm) exceeds that of the non-aqueous electrolyte (~1 - 10 mS / cm), thus achieving excellent rate performance, high power density, and low ohmic polarization. Among them, manganese oxides, Prussian blue analogs, conductive organic polymers, and vanadium-based compounds are the most commonly used cathode materials for aqueous zinc ion batteries. However, these materials have inevitable problems such as rapid capacity decline due to dissolution, low conductivity, poor cycling and rate performance, and complex reaction mechanisms. However, layered vanadium-based oxides have received extensive attention due to their open framework structure, rich valence states, various oxygen coordination polyhedra, and bonding modes. Compared with other structures such as tunnels or spinels, layered structure cathode materials provide a larger and adjustable interlayer distance, improve the reversibility of ion (de)insertion active sites, and reduce ion diffusion resistance to adapt to efficient Zn 2+ storage and have become one of the most promising materials Summary of the Invention

[0004] To solve the above-mentioned existing technical problems, one of the objectives of the present invention is to provide a PPy-Na doped with PPy2 V 6 O 16 ·3H 2 O electrode material and its preparation method.

[0005] To achieve the above invention object, the technical solution adopted by the present invention is:

[0006] A polypyrrole (PPy)-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material, and its preparation method includes the following steps:

[0007] Add vanadium pentoxide (V 2 O 5 ) and 30% hydrogen peroxide (H 2 O 2 ) to deionized water, stir at room temperature for 30 - 40 min; then, add sodium hydroxide (NaOH) to the obtained mixed solution and stir for 30 - 40 min; then add 0.5 M hydrochloric acid (HCl) to adjust the solution pH to 2; then, add polypyrrole (PPy) to the obtained light yellow solution and stir for 30 min; finally, transfer the obtained mixed solution to a reaction kettle for hydrothermal reaction, cool to room temperature, centrifuge and wash, and vacuum dry to obtain PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O.

[0008] Preferably, for the above PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material, by mass ratio, V 2 O 5 :NaOH = 1.00:0.29.

[0009] Preferably, for the above PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material, the addition amount of PPy is 60 - 180 μL.

[0010] More preferably, for the above PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material, the addition amount of PPy is 120 μL.

[0011] Preferably, a PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material, and the hydrothermal reaction is: transferring the obtained mixed solution into a stainless steel hydrothermal reaction kettle lined with polytetrafluoroethylene, and reacting at 175-185 °C for 30-31 h.

[0012] The second object of the present invention is to provide the application of the above-mentioned PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material as a positive electrode in an aqueous zinc-ion battery.

[0013] Preferably, for the above application, the method includes the following steps:

[0014] 1) Preparation of the positive electrode: After uniformly mixing the PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material with a binder and a conductive material, adding a small amount of N-methylpyrrolidone solution (NMP) as a solvent, mixing uniformly, directly applying it to a substrate carbon paper, drying it in a vacuum drying oven, taking it out, and obtaining a positive electrode coated with PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O;

[0015] 2) Preparation of the negative electrode: Sanding a zinc sheet with a thickness of 0.1 mm - 0.3 mm and a purity of 99% - 99.99% to remove the surface oxide layer, cutting the sanded zinc sheet into a circle with a diameter of 12 mm as the negative electrode;

[0016] 3) Using the positive electrode prepared in step 1) as the positive electrode, the negative electrode prepared in step 2) as the negative electrode, and an electrolyte of 3M zinc trifluoromethanesulfonate to obtain an aqueous zinc-ion battery.

[0017] More preferably, in the above application, in step 1), the binder is polyvinylidene fluoride (PVDF).

[0018] More preferably, in the above application, in step 1), the conductive material is Super-p.

[0019] More preferably, for the above application, by mass ratio, PPy-doped PPy-Na 2 V 6 O 16 ·3H 2The ratio of O electrode material : conductive material : binder is 7:2:1.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. In the present invention, by introducing PPy during the synthesis process, the conductivity and rate performance of the material are significantly improved, and the internal resistance is also reduced.

[0022] 2. In the present invention, the introduction of PPy expands the interlayer spacing, thereby improving the specific capacity and rate performance of the material during charge and discharge.

[0023] 3. The present invention has the characteristics of being inexpensive, environmentally friendly, and having relatively high safety.

[0024] 4. The present invention has relatively high energy density and power density.

[0025] 5. The synthesis process and assembly process of the present invention are simple, easy to operate and control, and suitable for large-scale production.

[0026] 6. After modification in the present invention, the capacity of the electrode material is increased from 265 mAh / g to 363 mAh / g.

[0027] 7. The method provided by the present invention is also applicable to other vanadium oxide and metal vanadate cathode materials. Description of the Drawings

[0028] Figure 1 It is the XRD spectra of Na 2 V 6 O 16 ·3H 2 O and PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O prepared in Example 1.

[0029] Figure 2 It is the TEM spectra of PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O prepared in Example 1.

[0030] Figure 3 It is the charge and discharge comparison diagram of time voltage of Na 2 V 6 O 16 ·3H 2 O and PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O prepared in Example 1.

[0031] Figure 4 is the Na prepared in Example 1 2 V 6 O 16 ·3H 2 O and PPy-doped Na 2 V 6 O 16 ·3H 2 O rate performance graph. Detailed implementation manners

[0032] The technical solutions of the present invention will be further described below, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall be covered by the protection scope of the present invention.

[0033] Example 1

[0034] (I) Preparation method of Na 2 V 6 O 16 ·3H 2 O is as follows:

[0035] Add 1.1 g of V 2 O 5 and 5 mL of 30% H 2 O 2 to 45 mL of deionized water. Stir the above solution at room temperature for 30 min, then add 0.32 g of NaOH to the solution; continue to stir at room temperature for 30 min, then adjust the pH of the solution to 2 with 0.5 M HCl. Finally, transfer the obtained mixed solution to a 50 mL stainless steel hydrothermal reaction kettle lined with polytetrafluoroethylene and maintain it at 180 °C for 30 h. Wash the obtained product with deionized water and ethanol several times, centrifuge, and dry the obtained dark red product in a vacuum oven at 60 °C for 12 h to obtain Na 2 V 6 O 16 ·3H 2 O nanorods.

[0036] (II) Preparation method of PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O is as follows:

[0037] Add 1.1 g of V 2 O 5 and 5 mL of 30% H 2 O 2Add it to 45 mL of deionized water, stir the above solution at room temperature for 30 min, then add 0.32 g of NaOH to the solution; continue to stir at room temperature for 30 min, and then adjust the pH of the solution to 2 with 0.5 M HCl; then, add 120 μL of PPy to the obtained light yellow solution and stir for 30 min. Finally, transfer the obtained mixed solution to a 50 mL stainless steel hydrothermal reaction kettle lined with polytetrafluoroethylene and keep it at 180 °C for 30 h. Wash the obtained product with deionized water and ethanol several times, centrifuge it, and dry the obtained dark red product in a vacuum oven at 60 °C for 12 h to obtain PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O nanorods.

[0038] (III) Detection

[0039] Figure 1 is the Na prepared in this example 2 V 6 O 16 ·3H 2 O and the XRD patterns of PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O. As can be seen from Figure 1 it, after PPy doping, the XRD pattern of the sample shows obvious changes, indicating that PPy has been successfully doped into Na 2 V 6 O 16 ·3H 2 O.

[0040] Figure 2 is the TEM image of PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O. As can be seen from Figure 2 it, the prepared PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O is a typical rod-like structure.

[0041] Figure 3 is Na 2 V 6 O 16 ·3H 2 O and the XRD patterns of PPy-doped PPy-Na 2 V 6 O 16 ·3H 2Charge-discharge comparison diagram of the time voltage of O. From Figure 3 It can be seen that PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O has a significantly longer discharge time than pure Na 2 V 6 O 16 ·3H 2 O.

[0042] Figure 4 It is Na 2 V 6 O 16 ·3H 2 O and PPy-doped Na 2 V 6 O 16 ·3H 2 O rate performance diagram. From Figure 4 It can be seen that PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O has a much higher specific capacity at different current densities than pure Na 2 V 6 O 16 ·3H 2 O.

[0043] Example 2 Preparation method of PVP-doped PPy-Na 2 V 6 O 16 ·3H 2 O

[0044] Add 1.1 g of V 2 O 5 and 5 mL of 30% H 2 O 2 to 45 mL of deionized water. Stir the above solution at room temperature for 30 min, then add 0.32 g of NaOH to the solution; continue to stir at room temperature for 30 min, and then adjust the pH of the solution to 2 with 0.5 M HCl; then, add 60 μL of PPy to the resulting light yellow solution and stir for 30 min. Finally, transfer the resulting mixed solution to a 50 mL stainless steel hydrothermal reaction kettle lined with polytetrafluoroethylene and keep it at 180 °C for 30 h. Wash the resulting product several times with deionized water and ethanol, centrifuge, and dry the obtained dark red product in a vacuum oven at 60 °C for 12 h to obtain PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O nanorods.

[0045] Example 3 PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O Preparation method is as follows

[0046] Add 1.1 g of V 2 O 5 and 5 mL of 30% H 2 O 2 to 45 mL of deionized water. Stir the above solution at room temperature for 30 min, then add 0.32 g of NaOH to the solution; continue to stir at room temperature for 30 min, and then adjust the pH of the solution to 2 with 0.5 M HCl; then, add 180 μL of PPy to the resulting light yellow solution and stir for 30 min. Finally, transfer the resulting mixed solution to a 50 mL stainless steel hydrothermal reaction kettle lined with polytetrafluoroethylene and keep it at 180 °C for 30 h. Wash the resulting product several times with deionized water and ethanol, centrifuge, and dry the obtained dark red product in a vacuum oven at 60 °C for 12 h to obtain PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O nanorods.

[0047] Example 4 Preparation of Aqueous Zinc-Ion Battery

[0048] 1) Preparation of the positive electrode sheet: Mix the PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material prepared in Example 1, Super-p, and PVDF uniformly by mass ratio of 7:2:1. Then, add a small amount of NMP as a solvent, mix well, and directly coat it on the substrate carbon paper. After drying in a vacuum drying oven and taking it out, obtain the positive electrode sheet coated with PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O, and set it aside;

[0049] 2) Preparation of the negative electrode sheet: Polish the zinc sheet with a thickness of 0.3 mm and a purity of 99.99% repeatedly with sandpaper to remove the surface oxide layer. Cut the polished zinc sheet into small round pieces with a diameter of 12 mm as the negative electrode sheet, and set it aside;

[0050] 3) Use the positive electrode sheet prepared in step 1) as the positive electrode and the negative electrode sheet prepared in step 2) as the negative electrode, and select 3 M zinc trifluoromethanesulfonate as the electrolyte to obtain an aqueous zinc-ion battery.

[0051] Preparation of Aqueous Zinc Ion Battery in Example 5

[0052] 1) Preparation of the positive electrode sheet: Mix the PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material, Super-p, and PVDF in a mass ratio of 7:2:1. After mixing evenly, add a small amount of NMP as a solvent. After mixing evenly, directly coat it on the substrate carbon paper. After drying in a vacuum drying oven and taking it out, obtain a positive electrode sheet coated with PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O for standby;

[0053] 2) Preparation of the negative electrode sheet: Polish a zinc sheet with a thickness of 0.3 mm and a purity of 99.99% repeatedly with sandpaper to remove the oxide layer on the surface. Cut the polished zinc sheet into small round pieces with a diameter of 12 mm as the negative electrode sheet for standby;

[0054] 3) Using the positive electrode sheet prepared in step 1 as the positive electrode and the negative electrode sheet prepared in step 2 as the negative electrode, select 3M zinc trifluoromethanesulfonate as the electrolyte to obtain an aqueous zinc ion battery.

[0055] Preparation of Aqueous Zinc Ion Battery in Example 6

[0056] 1) Preparation of the positive electrode sheet: Mix the PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O electrode material, Super-p, and PVDF in a mass ratio of 7:2:1. After mixing evenly, add a small amount of NMP as a solvent. After mixing evenly, directly coat it on the substrate carbon paper. After drying in a vacuum drying oven and taking it out, obtain a positive electrode sheet coated with PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O for standby;

[0057] 2) Preparation of the negative electrode sheet: Polish a zinc sheet with a thickness of 0.3 mm and a purity of 99.99% repeatedly with sandpaper to remove the oxide layer on the surface. Cut the polished zinc sheet into small round pieces with a diameter of 12 mm as the negative electrode sheet for standby;

[0058] 3) Using the positive electrode sheet prepared in step 1 as the positive electrode and the negative electrode sheet prepared in step 2 as the negative electrode, select 3M zinc trifluoromethanesulfonate as the electrolyte to obtain an aqueous zinc ion battery.

[0059] The three aqueous zinc ion batteries assembled in the above Examples 4 to 6 were subjected to electrochemical tests. We obtained that the electrochemical performance of Example 4 was the best, and the specific capacity at different current densities was significantly improved (as Figure 4 shown). In Example 4, by mass ratio, vanadium pentoxide: sodium hydroxide = 1:0.29, and the added PPy was 120 μL. The PPy-doped PPy-Na 2 V 6 O 16 ·3H 2 O nanorods were more orderly in size, providing more active sites, so it was easier to store more zinc ions, and at the same time promoted the insertion and extraction of zinc ions, thereby improving its electrochemical performance.

Claims

1. A polypyrrole-doped PPy-Na2V6O 16 3H2O electrode material, characterized in that The preparation method comprises the following steps: 1) Add V2O5, H2O2 and NaOH into deionized water, mix them and stir them at room temperature to make them fully mixed; 2) adding 0.5 M HCl to the obtained mixed solution to adjust the pH of the solution to 2 to obtain a light yellow solution; 3) Slowly add polypyrrole PPy to the light yellow solution, transfer the resulting mixed solution to a reactor for hydrothermal reaction, cool to room temperature, centrifuge for washing, and vacuum dry to obtain PPy-doped PPy-Na2V6O 16 3H2O electrode material.

2. A PPy-doped PPy-Na2V6O according to claim 1 16 3H2O electrode material, characterized in that In step 1), the mass ratio is V2O5:NaOH=1.00:0.

29.

3. A polypyrrole-doped PPy-Na2V6O according to claim 1 16 3H2O electrode material, characterized in that In step 2), the amount of PPy added is 60 to 180 μL.

4. A polypyrrole-doped PPy-Na2V6O according to claim 1 16 3H2O electrode material, characterized in that In step 3), the hydrothermal reaction is: transferring the obtained mixed solution to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene, and reacting at 175-185° C. for 30-31 hours.

5. A polypyrrole-doped PPy-Na2V6O according to any one of claims 1 to 4 16 Application of 3H2O electrode material as positive electrode in aqueous zinc ion battery.

6. The use according to claim 5, characterized in that: Here’s how: 1) Preparation of negative electrode sheet: A zinc sheet with a thickness of 0.1 mm to 0.3 mm and a purity of 99% to 99.99% is polished with sandpaper to remove the oxide layer on the surface, and the polished zinc sheet is cut into a circle with a diameter of 12 mm as a negative electrode sheet; 2) Coated with PPy-doped PPy-Na2V6O 16 The positive electrode sheet of ·3H2O is used as the positive electrode, the negative electrode sheet prepared in step 1) is used as the negative electrode, and the electrolyte is 3M zinc trifluoromethanesulfonate to obtain an aqueous zinc ion battery.

7. The use according to claim 6, characterized in that: The PPy-doped PPy-Na2V6O 16 The preparation method of the positive electrode sheet of 3H2O comprises the following steps: 16 After the 3H2O electrode material is mixed evenly with the binder and the conductive material, a small amount of NMP is added as a solvent. After mixing evenly, it is directly applied on the substrate carbon paper, dried in a vacuum drying oven, and taken out to obtain PPy-doped PPy-Na2V6O 16 ·3H2O positive electrode.

8. The use according to claim 7, characterized in that: The binder is PVDF.

9. The use according to claim 7, characterized in that: The conductive material is Super-p.

10. The use according to claim 7, characterized in that: According to the mass ratio, polypyrrole-doped PPy-Na2V6O 16 ·3H2O electrode material: conductive material: binder = 7:2:1.

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