A PVP-doped PVP-Ca 0.24 V2O5·H2O electrode material, preparation method thereof and application thereof in aqueous zinc ion battery

Abstract

The application discloses a PVP-doped PVP-Ca 0.24 The application discloses a V2O5.H2O electrode material, a preparation method thereof and application of the electrode material in a water-based zinc ion battery. V2O5 and Ca(OH)2 are added into deionized water, PVP is added into the obtained mixed solution, and stirring is continued; the obtained mixed solution is transferred into a polytetrafluoroethylene-lined stainless steel hydrothermal reaction kettle, hydrothermal reaction is carried out, cooling to room temperature is carried out, centrifugal cleaning is carried out, vacuum drying is carried out, and finally, the PVP-doped PVP-Ca 0.24 The application discloses a V2O5.H2O nanorod. By doping PVP into the electrode material, PVP is doped into CaV6O 16 3H2O to form the PVP-Ca 0.24 V2O5.H2O with phase transition and doped PVP, ion diffusion and charge transfer 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 the overall performance of the water-based zinc ion battery is effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of materials, and particularly relates to a PVP-doped PVP-Ca 0.24 V2O5·H2O electrode material, a preparation method thereof and application thereof in aqueous zinc ion batteries. BACKGROUND

[0002] Lithium ion batteries, as a new kind of secondary clean and renewable energy, have the advantages of high working voltage, light weight, large energy density, etc., and have been widely applied in the fields of electric tools, digital cameras, mobile phones, notebook computers, etc. However, the production cost of lithium ion batteries is high, the resource reserve of lithium is insufficient, and most of the organic electrolyte used is toxic and flammable, which has safety hazards and can cause environmental pollution. These problems seriously hinder the development and application of lithium ion batteries in the field of large-scale energy storage.

[0003] Among these systems, aqueous rechargeable zinc ion batteries are proposed as a viable alternative due to their high abundance, low cost, large theoretical capacity (819 mAh / g), low redox potential (-0.763 V vs. standard hydrogen electrode), high ionic conductivity of aqueous electrolyte (≈1.0 S / cm), high safety level and environmental friendliness. However, finding a viable cathode material is still a major obstacle on the road to commercialization of rechargeable zinc ion batteries. Among various rechargeable zinc ion anode materials, electrode materials such as manganese oxides, prussian blue compounds, etc. are used. These materials have the problems of inevitable dissolution and unsatisfactory reversible capacity, which lead to poor conductivity, poor rate performance, limited cycle performance, etc. However, layered vanadium-based oxides have attracted widespread attention due to their open framework structure, rich valence, multiple oxygen coordination polyhedron and bonding mode. These structural advantages provide multiple redox reactions and adjustable interlayer spacing and tunnel size to adapt to efficient Zn 2+ storage while achieving satisfactory reaction kinetics. The multiple valence states of vanadium element and the diverse open framework make it one of the most promising materials. SUMMARY

[0004] To solve the above-mentioned technical problems, one of the purposes of the present application is to provide a PVP-doped PVP-Ca 0.24 V2O5·H2O electrode material and a preparation method thereof.

[0005] To achieve the above-mentioned purposes of the application, the technical scheme adopted by the present application is as follows: a PVP-doped PVP-Ca 0.24 The V2O5·H2O electrode material and the preparation method thereof.

[0006] Vanadium pentoxide (V₂O₅) and calcium hydroxide (Ca(OH)₂) were added to deionized water and stirred at 70–80 °C for 3–4 h. Then, polyvinylpyrrolidone (PVP) was added to the resulting mixture and stirred for 30–40 min. The resulting mixture was transferred to a polytetrafluoroethylene-lined stainless steel hydrothermal reactor for hydrothermal reaction. After cooling to room temperature, the mixture was centrifuged, washed, and vacuum dried to obtain PVP-doped PVP-Ca. 0.24 V2O5·H2O

[0007] Preferably, the above-mentioned PVP-doped PVP-Ca 0.24 The V2O5·H2O electrode material, by mass ratio, has vanadium pentoxide: calcium hydroxide: polyvinylpyrrolidone = 1.00:0.20:0.04~0.30.

[0008] Preferably, the above-mentioned PVP-doped PVP-Ca 0.24 The V2O5·H2O electrode material, the hydrothermal reaction is to transfer the resulting mixed solution into a stainless steel hydrothermal reactor lined with polytetrafluoroethylene, and react at 175-185°C for 24-25 hours.

[0009] The second objective of this invention is to provide the above-mentioned PVP-doped PVP-Ca 0.24 Application of V2O5·H2O electrode material as positive electrode in aqueous zinc-ion batteries.

[0010] Preferably, the above application method includes the following steps:

[0011] 1) Preparation of the positive electrode: PVP-doped PVP-Ca 0.24 After the V2O5·H2O electrode material is thoroughly mixed with the binder and conductive material, a small amount of N-methylpyrrolidone solution (NMP) is added as a solvent. After mixing thoroughly, the mixture is directly coated onto the substrate carbon paper, dried in a vacuum drying oven, and then removed to obtain PVP-Ca coated with PVP dopant. 0.24 The positive electrode of V2O5·H2O;

[0012] 2) Preparation of negative electrode: 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. The polished zinc sheet is then cut into a circle with a diameter of 12 mm to serve as the negative electrode.

[0013] 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, and the electrolyte as 2M zinc trifluoromethanesulfonate, an aqueous zinc-ion battery is obtained.

[0014] Preferably, in the above application, in step 1), the adhesive is polyvinylidene fluoride (PVDF).

[0015] Preferably, in the above application, in step 1), the conductive material is Super-p.

[0016] Preferably, in the above applications, by mass ratio, PVP-doped PVP-Ca 0.24 V2O5·H2O electrode material: conductive material: binder = 7:2:1.

[0017] The beneficial effects of this invention are:

[0018] 1. This invention significantly improves the conductivity and cycle performance of the material and reduces its internal resistance by introducing PVP during the synthesis process.

[0019] 2. In this invention, the introduction of PVP causes a phase transition and changes the interlayer spacing, thereby improving the specific capacity and rate performance of the material during charging and discharging.

[0020] 3. This invention has the characteristics of low cost, environmental friendliness, and high safety.

[0021] 4. This invention has high energy density and power density.

[0022] 5. The present invention has a simple synthesis and assembly process, is easy to operate and control, and is suitable for continuous large-scale production.

[0023] 6. In this invention, after modification, the capacity of the electrode material is increased from 120mAh / g to 170mAh / g.

[0024] 7. The method provided by this invention is also applicable to other metal vanadate cathode materials. Attached Figure Description

[0025] Figure 1 It is CaV6O prepared in Example 1 16 ·3H2O and PVP-doped PVP-Ca 0.24 XRD pattern of V2O5·H2O.

[0026] Figure 2 It is the PVP-doped PVP-Ca prepared in Example 1 0.24 SEM image of V2O5·H2O.

[0027] Figure 3 It is CaV6O prepared in Example 1 16 ·3H2O and PVP-doped PVP-Ca 0.24 Cyclic voltammetry curve of V2O5·H2O.

[0028] Figure 4 It is CaV6O prepared in Example 116 ·3H2O and PVP-doped PVP-Ca 0.24 Specific capacity diagram of V2O5·H2O. Detailed Implementation

[0029] The technical solution of the present invention will be further described below, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention shall be covered within the protection scope of the present invention.

[0030] Example 1

[0031] (a) CaV6O 16 The preparation method of 3H2O is as follows:

[0032] 0.728 g V₂O₅ and 0.148 g Ca(OH)₂ were added to 80 mL of deionized water. The solution was stirred at 70 °C for 3 h. The resulting mixture was then transferred to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene and kept at 180 °C for 24 h. The product was washed several times with deionized water and ethanol. The resulting dark red product was dried in a vacuum oven at 60 °C for 12 h to obtain CaV₆O₅. 16 ·3H2O nanorods.

[0033] (II) PVP-doped PVP-Ca 0.24 The preparation method of V2O5·H2O is as follows:

[0034] 0.728 g V₂O₅ and 0.148 g Ca(OH)₂ were added to 80 mL of deionized water. The solution was stirred at 70 °C for 3 h. Then, 100 mg PVP was added to the resulting yellow solution and stirred for 30 min. The resulting mixture was transferred to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene and kept at 180 °C for 24 h. The product was washed several times with deionized water and ethanol, and the resulting dark green product was dried in a vacuum oven at 60 °C for 12 h to obtain PVP-doped PVP-Ca. 0.24 V2O5·H2O nanorods.

[0035] (III) Testing

[0036] Figure 1 This is the CaV6O prepared in this embodiment. 16 ·3H2O and PVP-doped PVP-Ca 0.24 XRD pattern of V₂O₅·H₂O. Figure 1 As can be seen, the XRD pattern of the sample showed significant changes after PVP doping, indicating that PVP was successfully incorporated into CaV6O. 16A phase transformation occurred in 3H2O, resulting in Ca. 0.24 V2O5·H2O.

[0037] Figure 2 It is PVP-doped PVP-Ca 0.24 SEM images of V₂O₅·H₂O. (From...) Figure 2 It can be seen that the prepared PVP-doped PVP-Ca 0.24 V2O5·H2O has a typical rod-like structure.

[0038] Figure 3 It is CaV6O 16 ·3H2O and PVP-doped PVP-Ca 0.24 Cyclic voltammetry curves of V₂O₅·H₂O. Figure 3 It can be seen that PVP-doped PVP-Ca 0.24 The area enclosed by V₂O₅·H₂O is significantly larger than that of pure CaV₆O. 16 ·3H2O, indicating that PVP-doped PVP-Ca 0.24 The capacity of V2O5·H2O is greater than that of pure CaV6O. 16 ·3H2O.

[0039] Figure 4 It is CaV6O 16 ·3H2O and PVP-doped PVP-Ca 0.24 Specific capacity diagram of V₂O₅·H₂O. (From...) Figure 4 It can be seen that PVP-doped PVP-Ca 0.24 The specific capacity and cycle stability of V2O5·H2O are much higher than those of pure CaV6O. 16 ·3H2O.

[0040] Example 2

[0041] PVP-doped PVP-Ca 0.24 The preparation method of V2O5·H2O is as follows:

[0042] 0.728 g V₂O₅ and 0.148 g Ca(OH)₂ were added to 80 mL of deionized water, and the solution was stirred at 70 °C for 3 h. Then, 30 mg PVP was added to the resulting yellow solution and stirred for 30 min. The resulting mixture was transferred to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene and kept at 180 °C for 24 h. The product was washed several times with deionized water and ethanol, and the resulting dark green product was dried in a vacuum oven at 60 °C for 12 h to obtain PVP-doped PVP-Ca. 0.24 V2O5·H2O nanorods.

[0043] Example 3

[0044] PVP-doped PVP-Ca 0.24 The preparation method of V2O5·H2O is as follows:

[0045] 0.728 g V₂O₅ and 0.148 g Ca(OH)₂ were added to 80 mL of deionized water, and the solution was stirred at 70 °C for 3 h. Then, 50 mg PVP was added to the resulting yellow solution and stirred for 30 min. The resulting mixture was transferred to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene and kept at 180 °C for 24 h. The product was washed several times with deionized water and ethanol, and the resulting dark green product was dried in a vacuum oven at 60 °C for 12 h to obtain PVP-doped PVP-Ca. 0.24 V2O5·H2O nanorods.

[0046] Example 4

[0047] PVP-doped PVP-Ca 0.24 The preparation method of V2O5·H2O is as follows:

[0048] 0.728 g V₂O₅ and 0.148 g Ca(OH)₂ were added to 80 mL of deionized water, and the solution was stirred at 70 °C for 3 h. Then, 200 mg PVP was added to the resulting yellow solution and stirred for 30 min. The resulting mixture was transferred to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene and kept at 180 °C for 24 h. The product was washed several times with deionized water and ethanol, and the resulting dark green product was dried in a vacuum oven at 60 °C for 12 h to obtain PVP-doped PVP-Ca. 0.24 V2O5·H2O nanorods.

[0049] Example 5: Preparation of an aqueous zinc-ion battery

[0050] 1) Preparation of the positive electrode: The PVP-doped PVP-Ca prepared in Example 1 was used... 0.24 V2O5·H2O electrode material was mixed with Super-p and PVDF at a mass ratio of 7:2:1 until homogeneous. A small amount of NMP was then added as a solvent, and the mixture was thoroughly mixed. The mixture was then directly coated onto a carbon paper substrate and dried in a vacuum drying oven to obtain PVP-Ca coated with PVP dopant. 0.24 Positive electrode plate of V2O5·H2O, for later use;

[0051] 2) Preparation of negative electrode: The zinc sheet with a thickness of 0.3 mm and a purity of 99.99% is repeatedly polished with sandpaper to remove the oxide layer on the surface. The polished zinc sheet is then cut into small round pieces with a diameter of 12 mm as negative electrode sheets for later use.

[0052] 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, and selecting 2M zinc trifluoromethanesulfonate as the electrolyte, an aqueous zinc-ion battery is obtained.

[0053] Example 6: Preparation of an aqueous zinc-ion battery

[0054] 1) Preparation of the positive electrode: The PVP-doped PVP-Ca prepared in Example 2 was used... 0.24 V2O5·H2O electrode material was mixed with Super-p and PVDF at a mass ratio of 7:2:1 until homogeneous. A small amount of NMP was then added as a solvent, and the mixture was thoroughly mixed. The mixture was then directly coated onto a carbon paper substrate and dried in a vacuum drying oven to obtain PVP-Ca coated with PVP dopant. 0.24 Positive electrode plate of V2O5·H2O, for later use;

[0055] 2) Preparation of negative electrode: The zinc sheet with a thickness of 0.3 mm and a purity of 99.99% is repeatedly polished with sandpaper to remove the oxide layer on the surface. The polished zinc sheet is then cut into small round pieces with a diameter of 12 mm as negative electrode sheets for later use.

[0056] 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, and selecting 2M zinc trifluoromethanesulfonate as the electrolyte, an aqueous zinc-ion battery is obtained.

[0057] Example 7: Preparation of an aqueous zinc-ion battery

[0058] 1) Preparation of the positive electrode: The PVP-doped PVP-Ca prepared in Example 3 was used... 0.24 V2O5·H2O electrode material was mixed with Super-p and PVDF at a mass ratio of 7:2:1 until homogeneous. A small amount of NMP was then added as a solvent, and the mixture was thoroughly mixed. The mixture was then directly coated onto a carbon paper substrate and dried in a vacuum drying oven to obtain PVP-Ca coated with PVP dopant. 0.24 Positive electrode plate of V2O5·H2O, for later use;

[0059] 2) Preparation of negative electrode: The zinc sheet with a thickness of 0.3 mm and a purity of 99.99% is repeatedly polished with sandpaper to remove the oxide layer on the surface. The polished zinc sheet is then cut into small round pieces with a diameter of 12 mm as negative electrode sheets for later use.

[0060] 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, and selecting 2M zinc trifluoromethanesulfonate as the electrolyte, an aqueous zinc-ion battery is obtained.

[0061] Example 8: Preparation of an aqueous zinc-ion battery

[0062] 1) Preparation of the positive electrode: The PVP-doped PVP-Ca prepared in Example 4 was used... 0.24 V2O5·H2O electrode material was mixed with Super-p and PVDF at a mass ratio of 7:2:1 until homogeneous. A small amount of NMP was then added as a solvent, and the mixture was thoroughly mixed. The mixture was then directly coated onto a carbon paper substrate, dried in a vacuum oven, and the resulting PVP-Ca electrode material was obtained. 0.24 Positive electrode plate of V2O5·H2O, for later use;

[0063] 2) Preparation of negative electrode: The zinc sheet with a thickness of 0.3 mm and a purity of 99.99% is repeatedly polished with sandpaper to remove the oxide layer on the surface. The polished zinc sheet is then cut into small round pieces with a diameter of 12 mm as negative electrode sheets for later use.

[0064] 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, and selecting 2M zinc trifluoromethanesulfonate as the electrolyte, an aqueous zinc-ion battery is obtained.

[0065] Electrochemical tests were conducted on the four aqueous zinc-ion batteries assembled in Examples 5-8 above. We found that Example 5 exhibited the best electrochemical performance, achieving a cycle life of 2700 cycles at a current density of 10 A / g and a capacity retention of 80.1% (e.g., ...). Figure 4 As shown in Example 5, vanadium pentoxide: calcium hydroxide: polyvinylpyrrolidone were formed at a mass ratio of 1:0.2:0.13, resulting in PVP-doped PVP-Ca. 0.24 The V2O5·H2O nanorods undergo a phase transition and become more uniform and ordered in size, providing more active sites. This makes it easier to store more zinc ions and promotes the insertion and extraction of zinc ions, thereby improving their electrochemical performance.

Claims

1. A PVP-doped PVP-Ca 0.24 V2O5·H2O electrode material, characterized in that, The preparation method includes the following steps: V₂O₅ and Ca(OH)₂ were added to deionized water and stirred at 70–80 °C for 3–4 h. Then, polyvinylpyrrolidone (PVP) was added to the resulting mixture and stirred for 30–40 min. The resulting mixture was transferred to a polytetrafluoroethylene-lined stainless steel hydrothermal reactor for hydrothermal reaction. After cooling to room temperature, the mixture was centrifuged, washed, and vacuum dried to obtain PVP-doped PVP-Ca. 0.24 V2O5·H2O.

2. The PVP-doped PVP-Ca according to claim 1 0.24 V2O5·H2O electrode material, characterized in that, By mass ratio, V2O5:Ca(OH)2:polyvinylpyrrolidone = 1.00:0.20:0.04~0.

30.

3. A PVP-doped PVP-Ca according to claim 1 0.24 V2O5·H2O electrode material, characterized in that, The hydrothermal reaction involves transferring the resulting mixed solution into a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and reacting it at 175–185°C for 24–25 hours.

4. A PVP-doped PVP-Ca according to any one of claims 1-3 0.24 Application of V2O5·H2O electrode material as positive electrode in aqueous zinc-ion batteries.

5. The application according to claim 4, characterized in that, The preparation method of the positive electrode includes the following steps: PVP-doped PVP-Ca 0.24 After the V2O5·H2O electrode material is thoroughly mixed with the binder and conductive material, a small amount of NMP is added as a solvent. After mixing thoroughly, the mixture is directly coated onto the substrate carbon paper, dried in a vacuum drying oven, and then removed to obtain PVP-Ca coated with PVP dopant. 0.24 Positive electrode of V2O5·H2O.

6. The application according to claim 5, characterized in that, The adhesive is PVDF.

7. The application according to claim 5, characterized in that, The conductive material is Super-p.

8. The application according to claim 5, characterized in that, By mass ratio, PVP-doped PVP-Ca 0.24 V2O5·H2O electrode material: conductive material: binder = 7:2:1.

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