Preparation method and application of phenolphthalein intercalated ammonium vanadate material

Abstract

The application discloses a preparation method and application of a phenolphthalein intercalated ammonium vanadate material. The phenolphthalein intercalated ammonium vanadate material is synthesized by a one-step solvothermal method, ammonium metavanadate is used as a vanadium source, a mixed solution of ethylene glycol and water is used as a reaction medium, and oxalic acid is used as a reducing agent, so that the phenolphthalein intercalated ammonium vanadate material is obtained under a solvothermal condition. The phenolphthalein molecules between layers of the material play a role of a support, and the hydrophobic phenolphthalein molecules can reduce direct contact between the material and water molecules, inhibit structural collapse and dissolution of the material in a cycle process and the like, and the material is applied to a water-based zinc ion battery as a positive electrode material, so that more excellent electrochemical performance and cycle stability are obtained.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method and application of a vanadium-based material, in particular to a preparation method and application of a phenolphthalein intercalated ammonium vanadate material. BACKGROUND

[0002] Lithium ion batteries (LIBs) have become a stable energy storage system due to their high energy density and long cycle life. However, the scarcity of lithium resources and the safety problems caused by the organic electrolyte used in LIBs limit their application in the power grid. In recent years, aqueous metal ion batteries (Zn 2+ , Ca 2+ , Mg 2+ and Al 2+ ) have attracted much attention due to their high safety, abundant resources and environmental friendliness. In particular, aqueous zinc ion batteries (ZIBs) have become one of the most promising candidates for the next generation of large-scale power grid energy storage systems due to the low redox potential of zinc metal (-0.76V vs. SHE), high theoretical specific capacity (820mAh g -1 ), stable chemical properties and low manufacturing cost.

[0003] Although ZIBs have the above advantages, the practical application of ZIBs is limited due to the lack of suitable positive electrode materials. At present, Prussian blue analogues, manganese-based materials, vanadium-based materials and covalent organic framework materials have been designed as positive electrode materials for ZIBs. Among them, vanadium-based materials have attracted more research interest due to their open framework crystal structure, multiple valence states of vanadium (V 2+ , V 3+ , V 4+ and V 5+ ) and abundant natural resources. However, the large atomic radius and mass of divalent Zn 2+ , and the strong electrostatic interaction between Zn 2+ and the material framework lead to the problem of structure collapse during repeated insertion / extraction of Zn 2+ , and the dissolution and side reaction of vanadium-based materials in aqueous electrolyte also lead to poor cycle stability.

[0004] Previous studies have shown that pre-intercalating molecules or ions between the layers can increase the interlayer distance and expand the diffusion channel, while serving as a pillar between the layers to achieve fast and stable zinc ion diffusion kinetics. Therefore, pre-intercalating molecules or ions between the layers of layered ammonium vanadate material is an effective method to improve the electrochemical performance of ammonium vanadate as a positive electrode material for aqueous zinc ion batteries. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of a phenolphthalein intercalated ammonium vanadate material with excellent electrochemical performance;

[0006] A second object of the present application is to provide the use of the phenolphthalein intercalated ammonium vanadate material prepared by the above method.

[0007] Technical solution: The preparation method of the phenolphthalein intercalated ammonium vanadate material provided by the present application comprises the following steps:

[0008] (1) Ammonium metavanadate and phenolphthalein are added to a mixed solution of an organic solvent and water, and stirred, heated to obtain a uniform mixed solution A;

[0009] (2) Oxalic acid is added to the mixed solution A, and stirred until brown to obtain a solution B;

[0010] (3) The solution B is subjected to hydrothermal reaction, and then the product is centrifuged, washed and dried to obtain the phenolphthalein intercalated ammonium vanadate material.

[0011] In step (1), the organic solvent is one or more of ethanol, ethylene glycol, and isopropyl alcohol.

[0012] In step (1), the molar ratio of ammonium metavanadate to phenolphthalein is 10-20:1.

[0013] In step (1), the volume ratio of ethylene glycol to water is 1:1-5.

[0014] In step (2), the mass of the added oxalic acid is determined according to the molar ratio of ammonium metavanadate to oxalic acid in the mixed solution A, which is 1:1-3.

[0015] In step (3), the temperature of the hydrothermal reaction is 140-200℃, and the time is 24-72h.

[0016] In step (1), the heating temperature is 70-90℃.

[0017] In step (3), the drying temperature is 50-80℃.

[0018] The phenolphthalein intercalated ammonium vanadate material prepared by the above method is applied in a water-based zinc ion battery.

[0019] In the application, the titanium foil coated with the phenolphthalein intercalated ammonium vanadate material prepared by the method of claim 1 is used as the positive electrode, the zinc foil is used as the negative electrode, the GF / D type glass fiber separator is used as the separator, and the zinc trifluoromethanesulfonate aqueous solution is used as the electrolyte.

[0020] Beneficial effects: Compared with the prior art, the present application has the following remarkable effects: (1) The hydrophobic organic small molecules are pre-inserted into the interlayer of the ammonium vanadate material, and the strong phenolphthalein molecules can act as interlayer pillars to relieve the material from the stress caused by the volume change of zinc ions during the charge and discharge process, thereby improving the cycle performance of the battery. 2+The structural collapse problem caused by repeated intercalation / deintercalation process. At the same time, the phenolphthalein molecule with hydrophobicity can reduce the direct contact of the material with water molecules, inhibit the dissolution and side reaction of the ammonium vanadate material in the aqueous electrolyte, and improve the cycle stability of the aqueous zinc ion battery.(2) The phenolphthalein intercalated ammonium vanadate material provided by the application can be synthesized by one-step hydrothermal method, the synthesis method is simple, the raw materials are widely used, which is helpful to develop the positive material of the aqueous zinc ion battery with stable performance and the aqueous zinc ion battery, and is suitable for large-scale production, and effectively helps the large-scale application of the aqueous zinc ion battery. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 XRD patterns of the phenolphthalein intercalated ammonium vanadate material prepared for Example 1 and the ammonium vanadate material prepared for Comparative Example 1;

[0022] Figure 2 Scanning electron microscope image of the phenolphthalein intercalated ammonium vanadate material prepared for Example 1;

[0023] Figure 3 Rate performance schematic diagram of the phenolphthalein intercalated ammonium vanadate material prepared for Example 1 and the ammonium vanadate material prepared for Comparative Example 1 as the positive material of the aqueous zinc ion battery;

[0024] Figure 4 Long cycle performance schematic diagram of the phenolphthalein intercalated ammonium vanadate material prepared for Example 1 and the ammonium vanadate material prepared for Comparative Example 1 as the positive material of the aqueous zinc ion battery under the current density of 2A / g. DETAILED DESCRIPTION

[0025] The application will be further described in detail below.

[0026] Example 1

[0027] A preparation method of a phenolphthalein intercalated ammonium vanadate material, comprising the following steps:

[0028] 1mmol of ammonium metavanadate and 0.1mmol of phenolphthalein were added to 80ml of a mixed solution of ethanol and water, stirred well, and heated to 70℃ to obtain a uniform mixed solution A, wherein V 乙二醇 :V 水 =1:1. 1mmol of oxalic acid was added to the mixed solution A to obtain a brown solution B, and then the brown solution B was transferred to a polytetrafluoroethylene lined hydrothermal reaction kettle, reacted at 140℃ for 72 hours, and after the reaction was completed, the product was centrifuged, washed, and dried at 50℃ for 12h to obtain the phenolphthalein intercalated ammonium vanadate material, and the scanning electron microscope image of the material is shown in Figure 2 .

[0029] A 2032 type button zinc ion battery was assembled using the phenolphthalein intercalated ammonium vanadate material as the positive electrode, a 0.05 mm thick zinc foil as the negative electrode, a GF / D type glass fiber as the separator, and a 3 mol / L zinc triflate aqueous solution as the electrolyte.

[0030] The prepared battery was subjected to electrochemical performance testing using a battery testing system. The rate performance testing conditions were tested at current densities of 0.1, 0.5, 1, 2, 3, and 5 A / g, and the rate performance schematic diagram is shown in FIG. 2A. The long cycle performance was tested by being cycled 1000 times at a current density of 2 A / g, and the long cycle performance schematic diagram is shown in FIG. 2B. Figure 3 Figure 4

[0031] Example 2

[0032] A method for preparing a phenolphthalein intercalated ammonium vanadate material includes the following steps:

[0033] 5 mmol of ammonium metavanadate and 0.25 mmol of phenolphthalein were added to a mixed solution of 80 ml of isopropyl alcohol and water, stirred well, and heated to 80°C to obtain a uniform mixed solution A, wherein V 乙二醇 :V 水 = 1:2. 8 mmol of oxalic acid was added to the mixed solution A, stirred to obtain a brown solution B, and then the brown solution B was transferred to a polytetrafluoroethylene lined hydrothermal reaction kettle, reacted at 180°C for 48 hours. After the reaction was completed, the product was centrifuged, washed, and dried at 70°C for 12 h to obtain the phenolphthalein intercalated ammonium vanadate material.

[0034] A 2032 type button zinc ion battery was assembled using the phenolphthalein intercalated ammonium vanadate material as the positive electrode, a 0.05 mm thick zinc foil as the negative electrode, a GF / D type glass fiber as the separator, and a 3 mol / L zinc triflate aqueous solution as the electrolyte.

[0035] The prepared battery was subjected to electrochemical performance testing using a battery testing system. The rate performance testing conditions were tested at current densities of 0.1, 0.5, 1, 2, 3, and 5 A / g, and the rate performance results are listed in Table 1. The long cycle performance was tested by being cycled 1000 times at a current density of 2 A / g, and the long cycle performance results are listed in Table 2.

[0036] Example 3

[0037] A method for preparing a phenolphthalein intercalated ammonium vanadate material includes the following steps:

[0038] ​​V 乙二醇 :V 水 = 1:3. 30 mmol of oxalic acid was added into the mixed solution A, and stirred to obtain a brown solution B. Then, the brown solution B was transferred into a polytetrafluoroethylene-lined autoclave for reaction at 190 °C for 36 h. After the reaction was completed, the product was centrifuged, washed, and dried at 70 °C for 12 h to obtain the phenolphthalein intercalated ammonium metavanadate material.

[0039] A 2032 type button zinc ion battery was assembled by using the phenolphthalein intercalated ammonium metavanadate material as the positive electrode, a 0.05 mm thick zinc foil as the negative electrode, a GF / D type glass fiber as the separator, and a 3 mol / L zinc trifluoromethanesulfonate aqueous solution as the electrolyte.

[0040] The prepared battery was subjected to electrochemical performance test by using a battery test system. The rate performance test was conducted at a current density of 0.1, 0.5, 1, 2, 3, and 5 A / g, and the results were listed in Table 1. The long cycle performance test was conducted at a current density of 2 A / g for 1000 cycles, and the results were listed in Table 2.

[0041] Example 4

[0042] A method for preparing a phenolphthalein intercalated ammonium metavanadate material, comprising the following steps:

[0043] V 乙二醇 :V 水 = 1:5. 25 mmol of oxalic acid was added into the mixed solution A, and stirred to obtain a brown solution B. Then, the brown solution B was transferred into a polytetrafluoroethylene-lined autoclave for reaction at 200 °C for 24 h. After the reaction was completed, the product was centrifuged, washed, and dried at 80 °C for 12 h to obtain the phenolphthalein intercalated ammonium metavanadate material.

[0044] A 2032 type button zinc ion battery was assembled by using the phenolphthalein intercalated ammonium metavanadate material as the positive electrode, a 0.05 mm thick zinc foil as the negative electrode, a GF / D type glass fiber as the separator, and a 3 mol / L zinc trifluoromethanesulfonate aqueous solution as the electrolyte.

[0045] The prepared battery was tested by a battery test system for electrochemical performance. The rate performance test conditions were tested at current densities of 0.1, 0.5, 1, 2, 3, and 5 A / g, and the rate performance results are listed in Table 1. The long cycle performance was tested at a current density of 2 A / g for 1000 cycles, and the long cycle performance results are listed in Table 2.

[0046] Comparative Example 1

[0047] Based on Example 1, different from Example 1, phenolphthalein was not used. The prepared battery was tested under the same test conditions, and the rate performance results are shown in Table 1, and the long cycle performance results are shown in Table 2. Figure 3 Figure 4

[0048] Comparative Example 2

[0049] Based on Example 2, different from Example 2, phenolphthalein was not used. The prepared battery was tested under the same test conditions, and the rate performance results are shown in Table 1, and the long cycle performance results are shown in Table 2.

[0050] Comparative Example 3

[0051] Based on Example 3, different from Example 3, phenolphthalein was not used. The prepared battery was tested under the same test conditions, and the rate performance results are shown in Table 1, and the long cycle performance results are shown in Table 2.

[0052] Comparative Example 4

[0053] Based on Example 4, different from Example 4, phenolphthalein was not used. The prepared battery was tested under the same test conditions, and the rate performance results are shown in Table 1, and the long cycle performance results are shown in Table 2.

[0054] Comparative Example 5

[0055] Based on Example 4, different from Example 4, the amount of phenolphthalein used was 3 mmol. The prepared battery was tested under the same test conditions, and the rate performance results are shown in Table 1, and the long cycle performance results are shown in Table 2.

[0056] Comparative Example 6

[0057] Based on Example 4, different from Example 4, the amount of oxalic acid used was 15 mmol. The prepared battery was tested under the same test conditions, and the rate performance results are shown in Table 1, and the long cycle performance results are shown in Table 2.

[0058] Table 1 ​​

[0059]

[0060] Table 2

[0061]

[0062] Result analysis:

[0063] From Figure 1 The XRD patterns of the phenolphthalein intercalated ammonium vanadate material and ammonium vanadate material prepared using Example 1 can be seen that the phenolphthalein intercalated ammonium vanadate material appears new diffraction peaks at 12.09°, 12.87°, 15.03°, 18.48°, 22.04° and 23.41°, which are caused by the phenolphthalein molecules embedded in the material layer.

[0064] From Figure 3 The rate performance of the phenolphthalein intercalated ammonium vanadate material and ammonium vanadate material prepared using Example 1 can be seen that the aqueous zinc ion battery using phenolphthalein intercalated ammonium vanadate as the positive electrode material obtains better rate performance, which can provide specific capacities of 358.99, 273.67, 245.54, 212.93 and 168.56 mAh / g at current densities of 0.1, 0.5, 1, 2 and 5 A / g, respectively. While the specific capacities of the aqueous zinc ion battery using ammonium vanadate as the positive electrode material at the same current densities are 367.51, 308.20, 266.20, 219.51 and 171.62 mAh / g, respectively. The better rate performance of the phenolphthalein intercalated ammonium vanadate material indicates that the embedding of phenolphthalein molecules is beneficial to the kinetics process of the electrode reaction, thereby improving the electrochemical performance of the material.

[0065] From Figure 4 The cycle performance of the phenolphthalein intercalated ammonium vanadate material and ammonium vanadate material prepared using Example 1 as the positive electrode material of the aqueous zinc ion battery at a current density of 2 A / g can be seen that the initial discharge specific capacity of the ammonium vanadate material is 204.66 mAh / g, and the discharge specific capacity after 700 cycles is 106.17 mAh / g, with a capacity retention rate of only 51.87%. While the initial discharge specific capacity of the phenolphthalein intercalated ammonium vanadate material is 216.65 mAh / g, and the specific capacity still remains at 194.52 mAh / g after 700 cycles, with a capacity retention rate of 89.78%. This indicates that the phenolphthalein intercalated ammonium vanadate material has better cycle stability as the positive electrode material of the aqueous zinc ion battery. This is attributed to the phenolphthalein molecules in the layer of the material playing a "pillar" role, and the hydrophobic phenolphthalein molecules can reduce the direct contact of the material with water molecules, thereby inhibiting the problems such as structural collapse and dissolution of the material during the cycle process, so that the aqueous zinc ion battery obtains better cycle stability and higher capacity retention rate.

Claims

1. Use of a phenolphthalein intercalated ammonium vanadate material in aqueous zinc ion batteries, characterized in that, The preparation method of the phenolphthalein intercalated ammonium vanadate material comprises the following steps: (1) adding ammonium metavanadate and phenolphthalein into a mixed solution of an organic solvent and water, stirring, heating, and obtaining a uniform mixed solution A; the organic solvent is one or more of ethanol, ethylene glycol and isopropyl alcohol; the molar ratio of the ammonium metavanadate and the phenolphthalein is 10-20:1; (2) adding oxalic acid into the mixed solution A, stirring until brown, and obtaining solution B; the mass of the added oxalic acid is determined according to the molar ratio of the ammonium metavanadate and the oxalic acid in the mixed solution A being 1:1-3; (3) performing hydrothermal reaction on the solution B, then centrifuging, washing and drying the product, and obtaining the phenolphthalein intercalated ammonium vanadate material.

2. Use of the phenolphthalein intercalated ammonium vanadate material according to claim 1 in aqueous zinc-ion batteries, characterized in that, In step (1), the volume ratio of the ethylene glycol and the water is 1:1-5.

3. Use of the phenolphthalein intercalated ammonium vanadate material according to claim 1 in aqueous zinc-ion batteries, characterized in that, In step (3), the temperature of the hydrothermal reaction is 140-200 ℃, and the time is 24-72 h.

4. Use of the phenolphthalein intercalated ammonium vanadate material according to claim 1 in aqueous zinc-ion batteries, characterized in that, In step (1), the heating temperature is 70-90 ℃.

5. Use of the phenolphthalein intercalated ammonium vanadate material according to claim 1 in aqueous zinc-ion batteries, characterized in that, In step (3), the drying temperature is 50-80 ℃.

6. Use of the phenolphthalein intercalated ammonium vanadate material according to claim 1 in aqueous zinc-ion batteries, characterized in that, The titanium foil coated with the phenolphthalein intercalated ammonium vanadate material is used as a positive electrode, the zinc foil is used as a negative electrode, the GF / D type glass fiber separator is used as a separator, and the zinc triflate aqueous solution is used as an electrolyte.

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