Metal ion intercalation vanadium dioxide as well as preparation method and application thereof

Abstract

The invention provides metal ion intercalation vanadium dioxide as well as a preparation method and application thereof, belongs to the technical field of aqueous iron ion batteries, and aims to solve the technical problem of low energy density of an aqueous iron ion battery positive electrode material. The preparation method of the metal ion intercalation vanadium dioxide comprises the following steps: dispersing vanadium pentoxide, a reducing agent and a metal source into a solvent to obtain a mixed solution; and reacting the mixed solution to obtain the metal ion intercalation vanadium dioxide nanosheet. The synthesis method provided by the invention is a one-step hydrothermal method, the synthesis method is relatively simple, environment-friendly and relatively low in cost, and the prepared material is a relatively uniform nanosheet. The prepared metal ion intercalation vanadium dioxide nanosheet is used as a positive electrode material of an iron ion battery, 284.32 mAh g <-1 > can be provided under the current density of 0.1 A g <-1 >, and the average discharge efficiency is as high as 99%.

Description

Technical Field

[0001] The invention belongs to the technical field of aqueous iron ion batteries, and in particular relates to a positive electrode active material. Background Art

[0002] With the rapid development of the global economy and science and technology, the overuse of fossil fuels has led to energy shortages and climate change problems. Therefore, the application of sustainable energy such as wind power, solar energy and wind power generation has received widespread attention. Energy storage systems provide support for the utilization of renewable energy. Among the many battery systems, lithium-ion batteries stand out due to their high specific energy density and mature technology. However, the limitation of lithium metal resources and the flammability of organic electrolytes in lithium-ion batteries have limited their large-scale application. Therefore, it is crucial to choose a battery system with abundant resources and high safety. At present, the battery systems that people are concerned about include sodium, potassium, magnesium, zinc, aluminum, calcium and iron. Among them, among these battery systems, the aqueous iron ion battery system has the following advantages: abundant iron resources, accounting for 5.6% of the abundance of the earth's crust; low cost; low redox potential (-0.44V relative to the standard hydrogen electrode) and high theoretical capacity (7557mAhcm -3 or 960mAhg -1 ).

[0003] For example, the patent publication number discloses an aqueous iron ion battery, the positive electrode of which includes a ferrous vanadate positive electrode material, and the electrolyte is an aqueous electrolyte. The ferrous vanadate positive electrode material is prepared by the following method: 1) mixing an iron source and a vanadium source in a molar ratio of 1:2 between iron and vanadium, and then mixing with a chelating agent and dispersing in water to form a sol, and then heating and stirring to obtain a wet gel; 2) drying the wet gel of step 1) to form a dry gel, and then pre-calcining it in a reducing atmosphere or a protective atmosphere, and then grinding it to obtain a powdered material; 3) calcining the powdered material of step 2) in a reducing atmosphere to obtain a ferrous vanadate positive electrode material. This patent uses ferrous vanadate positive electrode material as the positive electrode active material, and its specific capacity can reach up to 230mAh g -1 In addition, due to its unique tunnel-like structure, B-phase vanadium dioxide has applications in different battery systems, such as lithium-ion batteries, sodium-ion batteries, and zinc-ion batteries. When vanadium dioxide is used as the positive electrode material for aqueous iron-ion batteries, the typical open tunnel-like structure of B-phase vanadium dioxide is conducive to Fe 2+ The specific capacity can reach 223.85mAhg -1 However, the energy density of the cathode materials of the currently disclosed aqueous iron-ion batteries is still relatively low, which limits the practical application of iron-ion batteries. Summary of the invention

[0004] Aiming at the technical problem of low energy density of positive electrode materials for aqueous iron ion batteries, the present invention proposes a metal ion intercalated vanadium dioxide and its preparation method and application. The specific capacity of the prepared metal ion intercalated vanadium dioxide reaches 284.32 mAhg -1 , and it also has the advantages of high safety, stable structure, low cost and green environmental protection.

[0005] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] A method for preparing metal ion intercalated vanadium dioxide comprises the following steps: dispersing vanadium pentoxide, a reducing agent and a soluble metal salt in a solvent to obtain a mixed solution; reacting the mixed solution to obtain metal ion intercalated vanadium dioxide nanosheets.

[0007] The reducing agent is any one or more of lauric acid, citric acid, oxalic acid, cyclodextrin, bamboo fiber, polyethylene glycol, polyacrylic acid, polyvinyl alcohol, polyaniline, trimesic acid, polyvinyl pyrrolidone, fructose, glucose, sucrose and starch.

[0008] The soluble metal salt is any one or more of lithium salt, sodium salt, potassium salt, magnesium salt, calcium salt, barium salt, aluminum salt, cobalt salt, nickel salt and manganese salt.

[0009] The lithium salts are lithium chloride, lithium nitrate, lithium carbonate, and lithium acetate; the sodium salts are sodium chloride, sodium sulfate, sodium carbonate, sodium bicarbonate, sodium nitrate, and sodium acetate; the potassium salts are potassium chloride, potassium nitrate, potassium carbonate, potassium sulfate, and potassium acetate; the magnesium salts are magnesium chloride, magnesium sulfate, magnesium nitrate, and magnesium acetate; the calcium salts are calcium chloride, calcium nitrate, calcium bicarbonate, calcium dihydrogen phosphate, calcium gluconate, calcium lactate, and calcium acetate; the barium salts are barium chloride and barium nitrate; the aluminum salts are aluminum chloride, aluminum sulfate, aluminum nitrate, and aluminum acetate; the cobalt salts are cobalt chloride, cobalt nitrate, and cobalt sulfate; the nickel salts are nickel chloride, nickel nitrate, and nickel sulfate

[0010] Preferably, the soluble metal salt is a manganese salt; the manganese salt is any one or more of manganese acetate, manganese nitrate or manganese chloride.

[0011] The solvent is any one or more of water, anhydrous ethanol, glycerol, methanol and N,N-dimethylformamide.

[0012] The concentration of vanadium pentoxide in the mixed solution is 0.01-50 mmol / ml.

[0013] The molar ratio of the vanadium pentoxide to the reducing agent is 1:(0.1-2.5); the metal atoms in the soluble metal salt account for 0.1-20% of the molar amount of vanadium atoms in the vanadium pentoxide.

[0014] The reaction temperature is 120-180°C and the reaction time is 2-24h.

[0015] The invention discloses an application of metal ion intercalated vanadium dioxide in an aqueous iron ion battery, wherein the metal ion intercalated vanadium dioxide is used as a positive electrode material.

[0016] Beneficial effects of the present invention: The synthesis method provided by the present invention is simple, low-cost, green and environmentally friendly, and highly efficient, and the synthesized nanosheets are evenly distributed. The prepared metal ion intercalated vanadium dioxide has a 0.1A g -1 It can provide 284.32mAh g -1 , the charge and discharge efficiency is as high as 99%. Compared with the B-phase vanadium dioxide positive electrode material, the specific capacity of metal ion intercalated vanadium dioxide is much higher than that of vanadium dioxide, and it also has the advantages of high safety, stable structure, low cost and green environmental protection. In addition, its polarization voltage value of 0.307V is much lower than that of vanadium dioxide 0.411V, which also reflects the electrochemical advantages of the prepared metal ion intercalated vanadium dioxide positive electrode material. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is the SEM image of manganese ion intercalated vanadium dioxide in Example 1.

[0019] Figure 2 This is the XRD diagram of manganese ion intercalated vanadium dioxide in Example 1.

[0020] Figure 3 This is the SEM image of vanadium dioxide in Comparative Example 1.

[0021] Figure 4 It is a graph showing the change in specific capacity under different current densities for Comparative Example 1, Example 1, Example 2 and Example 3.

[0022] Figure 5 This is a graph showing the change in specific capacity at different current densities in Example 9.

[0023] Figure 6 This is a graph showing the change in specific capacity at different current densities in Example 10.

[0024] Figure 7 This is a graph showing the change in specific capacity at different current densities in Example 11. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] A method for preparing manganese ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0028] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 43 ml of deionized water and stir for 15 min. Then add 0.8195 g of citric acid monohydrate to the solution and continue stirring for 15 min. Add 0.06 g of manganese acetate tetrahydrate (wherein the amount of Mn atoms is equivalent to 5% of V) to the solution and stir for 1 h to obtain a yellow solution.

[0029] Step 2: Pour the mixed solution into a 100 ml reactor and react at 180°C for 12 hours. Collect the obtained black product.

[0030] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed manganese ion intercalated vanadium dioxide nanosheets (abbreviated as 5% MVO).

[0031] In this example 1, the obtained manganese ion intercalated vanadium dioxide nanosheets were analyzed by scanning electron microscopy. The results are as follows: Figure 1 It was found that the nanosheet structure was dispersed relatively evenly, and the width of the nanosheet was about 20-40 nanometers and the thickness was 20-30 nanometers.

[0032] Figure 2 The XRD pattern of manganese ion intercalated vanadium dioxide prepared in Example 1 is shown in FIG. Figure 2 It can be seen that the sample has sharp and obvious diffraction peaks, and no other impurity peaks are observed. In addition, the XRD pattern of the manganese ion intercalated vanadium dioxide sample prepared in Example 1 is basically consistent with the VO2(B) XRD standard spectrum, indicating that the manganese ion intercalated vanadium dioxide sample synthesized by this method still has a tunnel-like structure.

[0033] Example 2

[0034] A method for preparing manganese ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0035] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 43 ml of deionized water and stir for 15 min. Then add 0.8195 g of citric acid monohydrate to the solution and continue stirring for 15 min. Add 0.127 g of manganese acetate tetrahydrate (wherein the amount of Mn atoms is equivalent to 10% of V) to the solution and stir for 1 h to obtain a yellow solution.

[0036] Step 2: Pour the mixed solution into a 100 ml reactor and react at 180°C for 12 hours. Collect the obtained black product.

[0037] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed manganese ion intercalated vanadium dioxide nanosheets (abbreviated as 10% MVO).

[0038] Example 3

[0039] A method for preparing manganese ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0040] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 43 ml of deionized water and stir for 15 min. Then add 0.8195 g of citric acid monohydrate to the solution and continue stirring for 15 min. Add 0.191 g of manganese acetate tetrahydrate (wherein the amount of Mn atoms is equivalent to 15% of V) to the solution and stir for 1 h to obtain a yellow solution.

[0041] Step 2: Pour the mixed solution into a 100 ml reactor and react at 180°C for 12 hours. Collect the obtained black product.

[0042] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed manganese ion intercalated vanadium dioxide nanosheets (abbreviated as 15% MVO).

[0043] Example 4

[0044] A method for preparing manganese ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0045] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 250 ml of deionized water and stir for 15 min. Then add 0.8195 g of citric acid monohydrate to the solution and continue stirring for 15 min. Add 0.127 g of manganese acetate tetrahydrate (wherein the amount of Mn atoms is equivalent to 10% of V) to the solution and stir for 1 h to obtain a yellow solution.

[0046] Step 2: Pour the mixed solution into a 100 ml reactor and react at 120°C for 24 hours. Collect the obtained black product.

[0047] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed manganese ion intercalated vanadium dioxide nanosheets.

[0048] Example 5

[0049] A method for preparing manganese ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0050] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 5 ml of deionized water and stir for 15 min. Then add 0.0525 g of citric acid monohydrate to the solution and continue stirring for 15 min. Add 0.063 g of manganese chloride (wherein the amount of Mn atoms is equivalent to 10% of V) to the solution and stir for 1 h to obtain a yellow solution.

[0051] Step 2: Pour the mixed solution into a 100 ml reactor and react at 160°C for 2 hours. Collect the obtained black product.

[0052] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed manganese ion intercalated vanadium dioxide nanosheets.

[0053] Example 6

[0054] A method for preparing manganese ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0055] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 50 ml of deionized water and stir for 15 min. Then add 1.3125 g of citric acid monohydrate to the solution and continue stirring for 15 min. Add 0.09 g of manganese nitrate (wherein the amount of Mn atoms is equivalent to 10% of V) to the solution and stir for 1 h to obtain a yellow solution.

[0056] Step 2: Pour the mixed solution into a 100 ml reactor and react at 160°C for 2 hours. Collect the obtained black product.

[0057] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed manganese ion intercalated vanadium dioxide nanosheets.

[0058] Example 7

[0059] A method for preparing manganese ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0060] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 50 ml of deionized water and stir for 15 min. Then add 1.3125 g of citric acid monohydrate to the solution and continue stirring for 15 min. Add 0.254 g of manganese acetate tetrahydrate (wherein the amount of Mn atoms is equivalent to 20% of V) to the solution and stir for 1 h to obtain a yellow solution.

[0061] Step 2: Pour the mixed solution into a 100 ml reactor and react at 160°C for 2 hours. Collect the obtained black product.

[0062] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed manganese ion intercalated vanadium dioxide nanosheets.

[0063] Example 8

[0064] A method for preparing manganese ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0065] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 50 ml of deionized water and stir for 15 min. Then add 1.3125 g of citric acid monohydrate to the solution and continue stirring for 15 min. Add 1.27 mg of manganese acetate tetrahydrate (wherein the amount of Mn atoms is equivalent to 10% of V) to the solution and stir for 1 h to obtain a yellow solution.

[0066] Step 2: Pour the mixed solution into a 100 ml reactor and react at 160°C for 2 hours. Collect the obtained black product.

[0067] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed manganese ion intercalated vanadium dioxide nanosheets.

[0068] Example 9

[0069] A method for preparing potassium ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0070] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 50 ml of deionized water and stir for 15 min. Then add 0.5 g of lauric acid to the solution and continue stirring for 15 min. Add 0.053 g of potassium nitrate (wherein the amount of K atoms is equivalent to 10% of V) to the solution and stir for 1 h to obtain a mixed solution.

[0071] Step 2: Pour the mixed solution into a 100 ml reactor and react at 160°C for 12 hours. Collect the obtained product.

[0072] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed potassium ion intercalated vanadium dioxide nanosheets.

[0073] Example 10

[0074] A method for preparing calcium ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0075] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 50 ml of a mixed solvent consisting of anhydrous ethanol and water (volume ratio 1:1), and stir for 15 min. Then add 0.225 g of oxalic acid to the solution, and continue stirring for 15 min. Add 0.058 g of calcium chloride (wherein the amount of Ca atoms is equivalent to 10% of V) to the solution, and stir for 1 h to obtain a mixed solution.

[0076] Step 2: Pour the mixed solution into a 100 ml reactor and react at 160°C for 12 hours. Collect the obtained product.

[0077] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain evenly dispersed calcium ion intercalated vanadium dioxide nanosheets.

[0078] Embodiment 11

[0079] A method for preparing magnesium ion intercalated vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0080] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 50 ml of a mixed solvent of anhydrous ethanol and water (volume ratio 1:1), and stir for 15 min. Then add 0.225 g of oxalic acid to the solution, and continue stirring for 15 min. Add 0.07 g of magnesium acetate (wherein the amount of Mg atoms is equivalent to 10% of V) to the solution, and stir for 1 h to obtain a mixed solution.

[0081] Step 2: Pour the mixed solution into a 100 ml reactor and react at 160°C for 12 hours. Collect the obtained product.

[0082] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain uniformly dispersed magnesium ion intercalated vanadium dioxide nanosheets.

[0083] Comparative Example 1

[0084] A method for preparing vanadium dioxide as a positive electrode material for an iron ion battery comprises the following steps:

[0085] Step 1: Dissolve 0.4728 g of vanadium pentoxide in 43 ml of deionized water and stir for 15 min. Then add 0.8195 g of citric acid monohydrate to the solution and continue stirring for 1 h to obtain a yellow solution.

[0086] Step 2: Pour the mixed solution into a 100 ml reactor and react at 180°C for 12 hours. Collect the obtained black product.

[0087] Step 3: Wash the mixture with deionized water and ethanol alternately for three times, and dry the mixture at 60° C. to obtain vanadium dioxide nanosheets (VO2).

[0088] The vanadium dioxide nanosheets obtained in Comparative Example 1 were analyzed by scanning electron microscopy. Figure 3 It was found that its nanosheet structure was stacked and its nanosheet width and thickness were close to those of manganese ion intercalated vanadium dioxide nanosheets.

[0089] Performance Testing

[0090] The positive electrode active materials prepared in the above Examples 1-3, 9-11 and Comparative Example 1 were prepared into positive electrode slurry according to the mass ratio of positive electrode material: conductive agent (Super P): binder (polytetrafluoroethylene) = 7:2:1, and then coated on the current collector titanium foil to form a positive electrode, and the metal iron foil was used as the negative electrode to make a CR2025 button battery for performance testing. The charge and discharge cut-off voltage was 0-1V, and the charge and discharge rate was 0.1Ag. -1 , the test results are shown in Table 1.

[0091] Table 1

[0092] project Charge specific capacity (mAh / g) Discharge specific capacity (mAh / g) Charge and discharge efficiency (%) Example 1 286.90 284.32 99.1 Example 2 286.68 281.81 98.3 Example 3 285.93 282.21 98.7 Example 9 257.17 252.81 98.3 Example 10 250.14 246.58 98.5 Embodiment 11 247.43 243.06 98.2 Comparative Example 1 223.85 213.78 95.5

[0093] Figure 4 A graph showing the relationship between the change in specific capacity at different current densities for Comparative Example 1, Example 1, Example 2 and Example 3 is given. Figure 5 A graph showing the change in specific capacity at different current densities of Example 9 is given. Figure 6 A graph showing the change in specific capacity at different current densities of Example 10 is given. Figure 7 The relationship diagram of the specific capacity change under different current densities of Example 11 is given. From Table 1, Figure 4 , Figure 5 , Figure 6 and Figure 7 It can be seen that the battery made of manganese ion intercalated vanadium dioxide prepared in the embodiment has higher charge and discharge specific capacity and charge and discharge efficiency than potassium, calcium and magnesium.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing metal ion intercalated vanadium dioxide, characterized in that: The method comprises the following steps: dispersing vanadium pentoxide, a reducing agent and a soluble metal salt in a solvent to obtain a mixed solution; and reacting the mixed solution to obtain metal ion intercalated vanadium dioxide nanosheets.

2. The method for preparing metal ion intercalated vanadium dioxide according to claim 1, characterized in that: The reducing agent is any one or more of lauric acid, citric acid, oxalic acid, cyclodextrin, bamboo fiber, polyethylene glycol, polyacrylic acid, polyvinyl alcohol, polyaniline, trimesic acid, polyvinyl pyrrolidone, fructose, glucose, sucrose and starch.

3. The method for preparing metal ion intercalated vanadium dioxide according to claim 2, characterized in that: The soluble metal salt is any one or more of lithium salt, sodium salt, potassium salt, magnesium salt, calcium salt, barium salt, aluminum salt, cobalt salt, nickel salt and manganese salt.

4. The method for preparing metal ion intercalated vanadium dioxide according to claim 3, characterized in that: The soluble metal salt is a manganese salt; the manganese salt is any one or more of manganese acetate, manganese nitrate or manganese chloride.

5. The method for preparing metal ion intercalated vanadium dioxide according to claim 1, characterized in that: The solvent is any one or more of water, anhydrous ethanol, glycerol, methanol and N,N-dimethylformamide.

6. The method for preparing metal ion intercalated vanadium dioxide according to claim 1, characterized in that: The concentration of vanadium pentoxide in the mixed solution is 0.01-50 mmol / ml.

7. The method for preparing metal ion intercalated vanadium dioxide according to claim 6, characterized in that: The molar ratio of the vanadium pentoxide to the reducing agent is 1:(0.1-2.5); the metal atoms in the soluble metal salt account for 0.1-20% of the molar amount of vanadium atoms in the vanadium pentoxide.

8. The method for preparing metal ion intercalated vanadium dioxide according to claim 1, characterized in that: The reaction temperature is 120-180°C and the reaction time is 2-24h.

9. Metal ion intercalated vanadium dioxide prepared by the method according to any one of claims 1 to 8.

10. The use of the metal ion intercalated vanadium dioxide according to claim 9 in an aqueous iron ion battery, characterized in that: The metal ion intercalated vanadium dioxide is used as the positive electrode material.

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