1. A preparation method of a copper ion or bismuth ion doped vanadium oxide material is characterized by comprising the following steps:

the method comprises the following steps: preparation of precursor solution

Respectively dissolving vanadium pentoxide, a copper source or a bismuth source and glucose in water to obtain a vanadium pentoxide solution, a copper source solution or a bismuth source solution and a glucose solution;

uniformly mixing a hydrogen peroxide solution and the vanadium pentoxide solution, and then carrying out water bath reaction to obtain a mixed solution;

uniformly mixing the copper source solution or the bismuth source solution, the glucose solution and the mixed solution, and then carrying out water bath reaction to obtain the precursor solution;

wherein the copper source is copper acetate or copper acetate hydrate; the bismuth source is bismuth nitrate or bismuth nitrate hydrate;

step two: preparation of copper ion or bismuth ion doped vanadium oxide material

Placing the precursor solution obtained in the step one into a reaction kettle to carry out hydrothermal reaction or microwave hydrothermal reaction; and after the reaction is finished, washing and centrifuging, and then sequentially drying and annealing the obtained solid to obtain the copper ion or bismuth ion doped vanadium oxide material.

2. The preparation method of the copper ion or bismuth ion doped vanadium oxide material according to claim 1, wherein in the first step, the concentration of vanadium pentoxide in the vanadium pentoxide solution is 0.05-3 mmol/mL;

preferably, the concentrations of copper ions and bismuth ions in the copper source solution and the bismuth source solution are both 0.01-1 mmol/mL;

preferably, the concentration of glucose in the glucose solution is 0.1-1 mmol/mL.

3. The method for preparing a copper ion-or bismuth ion-doped vanadium oxide material according to claim 2, wherein in the first step, the concentration of the hydrogen peroxide solution is 30 wt%.

4. The method for preparing the copper ion or bismuth ion doped vanadium oxide material according to claim 1, wherein in the first step, the temperature of the water bath reaction is 30-90 ℃.

5. The method for preparing the copper ion or bismuth ion doped vanadium oxide material according to claim 1, wherein in the second step, the washing and centrifuging conditions are as follows: the centrifugation speed is 3000-12000 r/min, and the centrifugation lasts for 5 min.

6. The method for preparing the copper ion or bismuth ion doped vanadium oxide material according to claim 1, wherein in the second step, the hydrothermal reaction or microwave hydrothermal reaction conditions are as follows: the temperature is 120-200 ℃, and the reaction time is 2-12 h.

7. The method for preparing the copper ion or bismuth ion doped vanadium oxide material according to claim 1, wherein in the second step, the drying is air blast drying under the following conditions: the drying temperature is 50-120 ℃, and the drying time is 3-24 h.

8. The method for preparing the copper ion or bismuth ion doped vanadium oxide material according to claim 1, wherein in the second step, the annealing treatment conditions are as follows: the heating rate is 1-10 ℃/min, the heat preservation temperature is 100-300 ℃, and the heat preservation time is 1-8 h.

9. A copper ion or bismuth ion doped vanadium oxide material prepared by the method for preparing a copper ion or bismuth ion doped vanadium oxide material according to any one of claims 1 to 8.

10. Use of the copper ion-or bismuth ion-doped vanadium oxide material according to claim 9 as a positive electrode material for an aqueous zinc ion battery.

Background

Vanadium pentoxide has been widely used in battery materials due to its advantages of multi-valence state change, multiple structures and abundant resources. The excellent open layered structure of vanadium pentoxide allows the intercalation and deintercalation of ions during charging and discharging, and has been widely used in the field of aqueous zinc ion battery materials. However, since the interlayer spacing of vanadium pentoxide is limited, excessive zinc ion intercalation and deintercalation cannot be allowed, resulting in low battery capacity; during the ion shuttling process, the layered structure is easily destroyed, which results in instability of the battery; in an aqueous electrolyte, vanadium pentoxide is partially dissolved in the electrolyte, and the cycle stability of the battery is affected. Therefore, the preparation of a vanadium oxide electrode system with high capacity and high stability is the key point for realizing the application of the water-based zinc ion battery.

In recent years, researches on preparation of vanadium oxide materials and application of the vanadium oxide materials in cathode materials of water-based zinc-ion batteries are more and more, but simply changing the morphology of vanadium oxide or compounding vanadium oxide with carbon-based materials cannot well improve the capacity of vanadium oxide.

Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.

Disclosure of Invention

The invention aims to provide a copper ion or bismuth ion doped vanadium oxide material, and a preparation method and application thereof, so as to solve the problem that the capacity and stability of the anode material of the existing water-based zinc ion battery cannot meet the requirements.

In order to achieve the purpose, the invention provides the following technical scheme:

a preparation method of a copper ion or bismuth ion doped vanadium oxide material comprises the following steps:

the method comprises the following steps: preparation of precursor solution

Respectively dissolving vanadium pentoxide, a copper source or a bismuth source and glucose in water to obtain a vanadium pentoxide solution, a copper source solution or a bismuth source solution and a glucose solution;

uniformly mixing a hydrogen peroxide solution and the vanadium pentoxide solution, and then carrying out water bath reaction to obtain a mixed solution;

uniformly mixing the copper source solution or the bismuth source solution, the glucose solution and the mixed solution, and then carrying out water bath reaction to obtain the precursor solution;

wherein the copper source is copper acetate or copper acetate hydrate; the bismuth source is bismuth nitrate or bismuth nitrate hydrate;

step two: preparation of copper ion or bismuth ion doped vanadium oxide material

Placing the precursor solution obtained in the step one into a reaction kettle to carry out hydrothermal reaction or microwave hydrothermal reaction; and after the reaction is finished, washing and centrifuging, and then sequentially drying and annealing the obtained solid to obtain the copper ion or bismuth ion doped vanadium oxide material.

In the preparation method, preferably, in the first step, the concentration of vanadium pentoxide in the vanadium pentoxide solution is 0.05-3 mmol/mL.

In the above preparation method, preferably, the concentrations of copper ions and bismuth ions in the copper source solution and the bismuth source solution are both 0.01 to 1 mmol/mL.

In the above preparation method, preferably, the concentration of glucose in the glucose solution is 0.1 to 1 mmol/mL.

In the above production method, preferably, in the first step, the concentration of the hydrogen peroxide solution is 30 wt%.

In the preparation method, preferably, in the first step, the temperature of the water bath reaction is 30-90 ℃.

In the above preparation method, preferably, in the second step, the washing and centrifuging conditions are as follows: the centrifugation speed is 3000-12000 r/min, and the centrifugation lasts for 5 min.

In the above preparation method, preferably, in the second step, the hydrothermal reaction or microwave hydrothermal reaction conditions are: the temperature is 120-200 ℃, and the reaction time is 2-12 h.

In the above production method, preferably, the drying is air-blast drying under conditions of: the drying temperature is 50-120 ℃, and the drying time is 3-24 h.

In the above preparation method, preferably, in the second step, the annealing conditions are: the heating rate is 1-10 ℃/min, the heat preservation temperature is 100-300 ℃, and the heat preservation time is 1-8 h.

The invention also provides a copper ion or bismuth ion doped vanadium oxide material prepared by the preparation method.

The invention also provides application of the copper ion or bismuth ion doped vanadium oxide material as a water-based zinc ion battery positive electrode material.

Has the advantages that:

(1) according to the invention, copper ions or bismuth ions are effectively doped into the vanadium oxide material, and the copper ions or bismuth ions are doped into the vanadium oxide layer, so that the distance between the vanadium oxide layers is increased, the vanadium oxide structure is stabilized, and the prepared copper ion or bismuth ion doped vanadium oxide material has good electrochemical performance. For example, the initial discharge capacity of the copper ion doped vanadium oxide material can reach 331.85mAh/g under the current density of 0.2A/g, and the capacity retention rate can reach 86% after 100 cycles; and the capacity fading of the material is only 0.035% per cycle under the condition of current density of 2A/g.

(2) The preparation method provided by the invention is simple and convenient, the proportion of copper ions or bismuth ions and vanadium oxide can be easily regulated and controlled by changing the concentration of the reaction reagent, the reaction process is easy to control, the yield is high, and the preparation method is suitable for large-scale production.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. Wherein:

FIG. 1 is a schematic diagram illustrating the synthesis of a copper ion-or bismuth ion-doped vanadium oxide material according to the present invention;

FIG. 2 is a scanning electron microscope image of a copper ion-doped vanadium oxide material obtained by reaction in a 0.18mmol/mL vanadium oxide system in example 1 of the present invention;

FIG. 3 is a morphology diagram of a copper ion-doped vanadium oxide material obtained by reaction in a 0.18mmol/mL vanadium oxide system in example 1 of the present invention, wherein the left and right images in FIG. 3 are transmission electron microscope images and high resolution transmission electron microscope images, respectively;

FIG. 4 is a cyclic voltammogram of a copper ion-doped vanadium oxide material reacted in a 0.18mmol/mL vanadium oxide system at a scanning rate of 0.001V/s in example 1 of the present invention;

FIG. 5 is a cycle curve of a copper ion doped vanadium oxide material at 0.2A/g obtained by reacting in a 0.18mmol/mL vanadium oxide system in example 1 of the present invention;

FIG. 6 is a graph of rate performance of the copper ion doped vanadium oxide material obtained by the reaction in the vanadium oxide system of 0.18mmol/mL at the rate of 0.3, 0.5, 1, 3, 5A/g in example 1 of the present invention;

FIG. 7 is a cycle performance graph of the copper ion doped vanadium oxide material obtained by the reaction in the 0.18mmol/mL vanadium oxide system at 2A/g cycle 1000 times in example 1 of the present invention;

FIG. 8 is a cycle curve at 0.1A/g for the copper ion doped vanadium oxide material reacted in a 0.36mmol/mL vanadium oxide system in example 2 of this invention.

FIG. 9 is a graph of rate capability of the copper ion doped vanadium oxide material obtained by the reaction in the 0.36mmol/mL vanadium oxide system at the rate of 0.3, 0.5, 1, 3, 5A/g in example 2 of the present invention.

FIG. 10 is a graph of the cycle performance of the bismuth ion doped vanadium oxide material reacted in a 0.36mmol/mL vanadium oxide system at 0.1A/g for 100 cycles in example 5 of the present invention.

FIG. 11 is a graph of rate performance of the bismuth ion doped vanadium oxide material obtained by the reaction in the 0.36mmol/mL vanadium oxide system in example 5 of the present invention at rates of 0.3, 0.5, 1, 3, and 5A/g.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

Vanadium pentoxide has been widely used in battery materials because of its advantages of multi-valence state change, multiple structures and abundant resources. The excellent open type layered structure can allow the intercalation and deintercalation of ions during charging and discharging, and is widely applied in the field of water-based zinc ion battery materials. However, since the interlayer spacing of vanadium pentoxide is limited, excessive zinc ion intercalation and deintercalation cannot be allowed, resulting in low battery capacity; during the ion shuttling process, the layered structure is easily destroyed, which results in instability of the battery; in an aqueous electrolyte, vanadium pentoxide is partially dissolved in the electrolyte, and the cycle stability of the battery is affected.

At present, aiming at the defects of single material performance, in an improvement method of vanadium oxide as a positive electrode material of an aqueous zinc ion battery, metal ions are doped into the vanadium oxide, and the doped vanadium oxide has higher capacity and better cycle stability. The copper ion or bismuth ion doped vanadium oxide material is characterized in that copper ions or bismuth ions are embedded into the vanadium oxide layers, so that the distance between the vanadium oxide layers is increased, the vanadium oxide structure is stabilized, a large number of zinc ions can be conveniently embedded and separated during charging and discharging, the capacity of the copper ion or bismuth ion doped vanadium oxide material is increased, the ion diffusivity is improved, and the cycling stability is good.

The copper ion or bismuth ion doped vanadium oxide material of the invention is used as the positive electrode material of an aqueous zinc ion battery, and the preparation process is shown in figure 1, wherein the negative electrode is zinc foil. Copper ions or bismuth ions are doped between vanadium oxide layers, so that the distance between the vanadium oxide layers is increased, and the vanadium oxide structure is stabilized, so that the prepared copper ion or bismuth ion doped vanadium oxide material has good electrochemical performance. For example, the initial discharge capacity of the copper ion doped vanadium oxide material can reach 331.85mAh/g under the current density of 0.2A/g, and the capacity retention rate can reach 86% after 100 cycles; and the capacity fading of the material is only 0.035% per cycle under the condition of current density of 2A/g.

The preparation method of the copper ion or bismuth ion doped vanadium oxide material comprises the following steps:

the method comprises the following steps: preparation of precursor solution

Dispersing a certain amount of vanadium pentoxide, copper acetate (or bismuth nitrate) and glucose in 10-15 mL (such as 10mL, 11mL, 12mL, 13mL, 14mL and 15mL) of aqueous solution respectively, uniformly stirring, adding 1-10 mL (such as 1mL, 2mL, 3mL, 4mL, 5mL, 6mL, 7mL, 8mL, 9mL and 10mL) of hydrogen peroxide solution into the vanadium pentoxide solution, uniformly mixing all the solutions, and then carrying out water bath reaction; specifically, the method comprises the following steps:

dissolving a certain amount of vanadium pentoxide in deionized water, and recording the solution as a solution I (namely a first solution);

dissolving a certain amount of copper acetate (or bismuth nitrate) in deionized water, and recording the solution as a second solution;

dissolving a certain amount of glucose in deionized water, and recording the solution as solution III (namely a third solution);

dropping a hydrogen peroxide solution into the solution I, continuously stirring at the speed of 500r/min for 10min, carrying out the reaction at room temperature (25 ℃), and continuously stirring for 20min under the water bath condition of 30-90 ℃ (such as 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃ and 90 ℃), and recording as a solution II (namely a fourth solution);

adding the solution II and the solution III into the obtained solution IV, and continuously stirring for 10min under the water bath condition of 30-90 ℃ (such as 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃ and 90 ℃) to obtain precursor liquid;

wherein the concentration of vanadium pentoxide in the solution (i) is 0.05-3 mmol/mL (e.g., 0.05mmol/mL, 0.07mmol/mL, 0.09mmol/mL, 0.1mmol/mL, 0.15mmol/mL, 0.35mmol/mL, 0.5mmol/mL, 0.75mmol/mL, 1mmol/mL, 1.25mmol/mL, 1.5mmol/mL, 1.75mmol/mL, 2mmol/mL, 2.25mmol/mL, 2.5mmol/mL, 2.75mmol/mL, 3 mmol/mL);

the concentration of copper acetate (or bismuth nitrate) in the solution (II) is 0.01 to 1mmol/mL (e.g., 0.01mmol/mL, 0.03mmol/mL, 0.05mmol/mL, 0.06mmol/mL, 0.07mmol/mL, 0.09mmol/mL, 0.1mmol/mL, 0.15mmol/mL, 0.35mmol/mL, 0.5mmol/mL, 0.75mmol/mL, 1 mmol/mL);

the concentration of glucose in the solution (c) is 0.1 to 1mmol/mL (e.g., 0.1mmol/mL, 0.15mmol/mL, 0.35mmol/mL, 0.5mmol/mL, 0.75mmol/mL, 1 mmol/mL);

the mass fraction of the hydrogen peroxide solution is 30 wt%;

step two: preparation of copper ion or bismuth ion doped vanadium oxide material

Putting the precursor solution obtained in the step one into a polytetrafluoroethylene reaction kettle for hydrothermal reaction or microwave hydrothermal reaction, wherein the filling degree is 30-70% (such as 30%, 40%, 50%, 60%, 70%); after the reaction is finished, washing the product obtained by centrifugal treatment through deionized water and alcohol alternately, drying the obtained solid by blowing air, and then carrying out high-temperature annealing treatment to obtain a copper ion or bismuth ion doped vanadium oxide material, specifically a nanosheet material;

specifically, the conditions of the treatment in each step involved in the step two are as follows:

the washing and centrifuging conditions are as follows: centrifuging at 3000-12000 r/min (such as 3000r/min, 5000r/min, 7000r/min, 9000r/min and 12000r/min) for 5 min;

the hydrothermal reaction or microwave hydrothermal reaction conditions are as follows: the hydrothermal temperature is 120-200 ℃ (for example, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃ and 200 ℃), and the reaction time is 2-12 h (for example, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h and 12 h);

the air drying conditions were: drying at 50-120 deg.C (such as 50 deg.C, 60 deg.C, 70 deg.C, 80 deg.C, 90 deg.C, 100 deg.C, 110 deg.C, 120 deg.C) for 3-24 h (such as 3h, 6h, 9h, 12h, 15h, 18h, 21h, 24 h);

the high-temperature annealing conditions are as follows: the heating rate is 1-10 ℃/min (e.g., 1 ℃/min, 2 ℃/min, 3 ℃/min, 4 ℃/min, 5 ℃/min, 6 ℃/min, 7 ℃/min, 8 ℃/min, 9 ℃/min, 10 ℃/min), the holding temperature is 100-300 ℃ (e.g., 100 ℃, 120 ℃, 140 ℃, 160 ℃, 180 ℃, 200 ℃, 220 ℃, 240 ℃, 260 ℃, 280 ℃, 300 ℃), and the holding time is 1-8 h (e.g., 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8 h).

The invention also provides application of the copper ion or bismuth ion doped vanadium oxide material as a positive electrode material in an aqueous zinc ion battery.

The copper ion or bismuth ion doped vanadium oxide material can increase the interlayer spacing of vanadium oxide, stabilize the vanadium oxide sheet layer structure and increase the ion diffusion rate, and experiments prove that the copper ion or bismuth ion doped vanadium oxide material has excellent electrochemical performance.

The invention is further described below with reference to specific examples.

Example 1

The embodiment specifically provides a copper ion doped vanadium oxide material, and the preparation method specifically comprises the following steps:

the method comprises the following steps: preparation of precursor solution

327mg (1.8mmol) of vanadium pentoxide (V)₂O₅) Dispersing in 10mL of deionized water, and recording as a solution I, wherein the concentration of vanadium pentoxide is 0.18 mmol/mL;

179mg of copper acetate (C)₄H₆CuO₄·H₂O, 0.9mmol) is dissolved in 15mL of deionized water and is recorded as a solution II, wherein the concentration of copper acetate is 0.06 mmol/mL;

198mg of glucose (C)₆H₁₂O₆1.1mmol) in 10mL of deionized water, and recording the solution as solution (c), wherein the concentration of glucose is 0.11 mmol/mL;

3mL of hydrogen peroxide solution (H)₂O₂) Dropwise adding the mixture into the solution I, continuously stirring for 10min, reacting at room temperature (25 ℃), placing the mixture into a water bath kettle at 50 ℃ for water bath reaction for 20min after the reaction is finished, and obtaining a solution IV after the reaction is finished;

adding the solution II and the solution III into the solution IV, and carrying out water bath reaction at 50 ℃ for 10min to obtain a precursor solution after the reaction is finished;

step two: preparation of copper ion doped vanadium oxide material

Pouring the precursor solution obtained in the step one into a polyethylene tetrafluoro reaction kettle, and carrying out hydrothermal reaction at 180 ℃ for 12 hours; cooling the reaction product to room temperature (25 ℃) along with the furnace after the reaction is finished, washing the reaction product with deionized water and alcohol alternately, and centrifuging the reaction product, wherein the centrifugation speed is 8000r/min, and the centrifugation lasts for 5 min; then, the reactant after washing and centrifugal treatment is dried by air blowing at 80 ℃ for 24 hours; and then annealing at 200 ℃ for 120min, wherein the heating rate is 5 ℃/min, and thus the copper ion doped vanadium oxide material can be obtained.

A schematic diagram of the synthesis of the copper ion-doped vanadium oxide material in this embodiment is shown in fig. 1, and in the obtained copper ion-doped vanadium oxide material, copper ions are embedded between vanadium oxide layers, so that the distance between the vanadium oxide layers is increased, and the vanadium oxide structure is stabilized.

Fig. 2 shows the morphology of the copper ion-doped vanadium oxide material prepared in this embodiment, the copper ion-doped vanadium oxide material is a nanosheet, the width of the nanosheet is 70-160 nm, the length of the nanosheet is 200-500 nm, the average thickness of the nanosheet is 22nm, and the nanosheet has a smooth and neat surface.

FIG. 3 is a transmission electron micrograph and a high resolution transmission electron micrograph of the copper ion doped vanadium oxide material prepared in this example, and the left image of FIG. 3 shows that the copper ion doped vanadium oxide material has a typical layered structure with a layer spacing ofThe right graph of fig. 3 shows that the lattice spacing corresponding to the (001) crystal plane of the copper ion doped vanadium oxide material is 0.65 nm.

The copper ion doped vanadium oxide material prepared by the method is suitable for a positive electrode material of an aqueous zinc ion battery, and can be assembled with a metal zinc (such as zinc foil) negative electrode to form a full battery. The cyclic voltammogram of the copper ion doped vanadium oxide material prepared in this example is shown in fig. 4, and the copper ion doped vanadium oxide material has three pairs of redox peaks at 1.309/1.344, 0.902/1.024 and 0.51/0.717V, which corresponds to the intercalation and deintercalation processes of zinc ions during charging and discharging. The copper ion doped vanadium oxide material has good cyclic voltammetry curve overlapping performance, reflects that the material has good structure reversibility and has excellent electrochemical performance.

FIG. 5 is a graph showing the cycle performance of the copper ion-doped vanadium oxide material of this example at a current density of 0.2A/g. As can be seen from the figure, the initial discharge specific capacity of the copper ion doped vanadium oxide material can reach 331.85mAh/g, and the capacity retention rate can reach 86% after 100 cycles. In addition, the copper ion doped vanadium oxide material of the present embodiment also has a better rate capability as shown in fig. 6, and at the rates of 0.3, 0.5, 1, 3, and 5A/g, the corresponding capacities are 330.8, 318.3, 294.7, 247.8, and 224.8mAh/g, respectively, even if the current is recovered from 5A/g to 0.3A/g, the same rate capability of the copper ion doped vanadium oxide material has a small change, which indicates that the material has a better rate conversion capability.

FIG. 7 is a graph of the cycle performance of copper ion doped vanadium oxide material at 2A/g for 1000 cycles. It can be clearly seen that the material still has good stability under high power charge-discharge conditions, and the average capacity loss per cycle is only 0.035%.

Example 2

The embodiment specifically provides a copper ion doped vanadium oxide material, and the preparation method specifically comprises the following steps:

the method comprises the following steps: preparation of precursor solution

655mg (3.6mmol) of vanadium pentoxide (V)₂O₅) Dispersing in 10mL of deionized water, and recording as a solution I, wherein the concentration of vanadium pentoxide is 0.36 mmol/mL;

179mg of copper acetate (C)₄H₆CuO₄·H₂O, 0.9mmol) is dissolved in 15mL of deionized water and is recorded as a solution II, wherein the concentration of copper acetate is 0.06 mmol/mL;

198mg of glucose (C)₆H₁₂O₆1.1mmol) in 10mL of deionized water, and recording the solution as solution (c), wherein the concentration of glucose is 0.11 mmol/mL;

3mL of hydrogen peroxide solution (H)₂O₂) Dropwise adding the mixture into the solution I, continuously stirring for 10min, reacting at room temperature (25 ℃), placing the mixture into a water bath kettle at 50 ℃ for water bath reaction for 20min after the reaction is finished, and obtaining a solution IV after the reaction is finished;

adding the solution II and the solution III into the solution IV, and carrying out water bath reaction at 50 ℃ for 10min to obtain a precursor solution after the reaction is finished;

step two: preparation of copper ion doped vanadium oxide material

Pouring the precursor solution obtained in the step one into a polyethylene tetrafluoro reaction kettle, and carrying out hydrothermal reaction at 180 ℃ for 12 hours; cooling the reaction product to room temperature (25 ℃) along with the furnace after the reaction is finished, washing the reaction product with deionized water and alcohol alternately, and centrifuging the reaction product, wherein the centrifugation speed is 8000r/min, and the centrifugation lasts for 5 min; then, the reactant after washing and centrifugal treatment is dried by air blowing at 80 ℃ for 24 hours; and then annealing at 200 ℃ for 120min, wherein the heating rate is 5 ℃/min, and thus the copper ion doped vanadium oxide material can be obtained.

The cycle performance of the copper ion doped vanadium oxide material of this example at 0.1A/g for 100 cycles is shown in fig. 8, from which it can be seen that the capacity gradually increased during the first ten cycles due to the cell activation process. The initial discharge capacity of the material can reach 330.9mAh/g, and the capacity after activation is increased to 344.8 mAh/g. FIG. 9 is a graph of rate capability of the material at 0.3, 0.5, 1, 3, 5A/g rates, corresponding capacities are 268.2, 265.7, 255.1, 223.4, 206.1mAh/g, respectively, even if the current is restored from 5A/g to 0.3A/g, the same rate capacity change of the copper ion doped vanadium oxide material is small, which indicates that the material has better rate conversion performance.

Example 3

The preparation method of the copper ion doped vanadium oxide material of the embodiment is different from that of the embodiment 1 in that: 250mg (1.4mmol) of vanadium pentoxide is dispersed in 10mL of deionized water (the concentration is 0.14mmol/mL), and other parameters are the same as those in example 1, and are not repeated.

The initial discharge capacity of the copper ion doped vanadium oxide material can reach 237mAh/g under 0.1A/g, and the electrochemical performance is excellent.

Example 4

The preparation method of the copper ion doped vanadium oxide material of the embodiment is different from that of the embodiment 1 in that: 163mg (0.9mmol) of vanadium pentoxide was dispersed in 10mL of deionized water (concentration: 0.09mmol/mL), and other parameters were the same as those in example 1 and thus the details thereof were omitted.

The initial discharge capacity of the copper ion doped vanadium oxide material can reach 231mAh/g under 0.1A/g, and the electrochemical performance is excellent.

Example 5

The embodiment specifically provides a bismuth ion doped vanadium oxide material, and the preparation method specifically comprises the following steps:

the method comprises the following steps: preparation of precursor solution

650mg (3.6mmol) of vanadium pentoxide (V)₂O₅) Dispersing in 10mL of deionized water, and recording as a solution I, wherein the concentration of vanadium pentoxide is 0.36 mmol/mL;

430mg of bismuth nitrate (Bi (NO)₃)₃·6H₂O, 0.9mmol) is dissolved in 10mL of deionized water and is recorded as a solution II, wherein the concentration of bismuth nitrate is 0.18 mmol/mL;

198mg of glucose (C)₆H₁₂O₆1.1mmol) in 10mL of deionized water, and recording the solution as solution (c), wherein the concentration of glucose is 0.11 mmol/mL;

3mL of hydrogen peroxide solution (H)₂O₂) Dropwise adding the mixture into the solution I, continuously stirring for 10min, reacting at room temperature (25 ℃), placing the mixture into a water bath kettle at 50 ℃ for water bath reaction for 20min after the reaction is finished, and obtaining a solution IV after the reaction is finished;

adding the solution II and the solution III into the solution IV, and carrying out water bath reaction at 50 ℃ for 10min to obtain a precursor solution after the reaction is finished;

step two: preparation of bismuth ion-doped vanadium oxide material

Pouring the precursor solution obtained in the step one into a polytetrafluoroethylene reaction kettle, and carrying out microwave hydrothermal reaction for 2 hours at 200 ℃, wherein the microwave power is 700W; cooling the reaction product to room temperature (25 ℃) along with the furnace after the reaction is finished, washing the reaction product with deionized water and alcohol alternately, and centrifuging the reaction product, wherein the centrifugation speed is 8000r/min, and the centrifugation lasts for 5 min; then, the reactant after washing and centrifugal treatment is dried by air blowing at 80 ℃ for 24 hours; and then annealing at 200 ℃ for 120min, wherein the heating rate is 5 ℃/min, and the bismuth ion doped vanadium oxide material can be obtained.

FIG. 10 is a graph of the cycling performance of the bismuth ion doped vanadium oxide material of this example at 0.1A/g for 100 cycles. As can be seen, the first charge capacity can reach 263mAh/g, and the capacity can be maintained at 86% after 100 cycles. Fig. 11 is a rate performance graph of the bismuth ion doped vanadium oxide material at rates of 0.3, 0.5, 1, 3 and 5A/g, the corresponding capacities are 313, 309, 296, 267 and 245mAh/g, even if the current is restored from 5A/g to 0.3A/g, the same rate capacity change of the bismuth ion doped vanadium oxide material is small, which indicates that the material has better rate conversion performance.

Example 6

The preparation method of the bismuth ion doped vanadium oxide material of the embodiment is different from that of the embodiment 5 in that: 1300mg of vanadium pentoxide was dispersed in 10mL of deionized water, and the rest were the same as in example 5 and will not be described again.

The initial discharge capacity of the bismuth ion doped vanadium oxide material of the embodiment can reach 391mAh/g under 0.1A/g, the capacity after activation is increased to 406mAh/g, and the electrochemical performance is excellent.

Example 7

The preparation method of the bismuth ion doped vanadium oxide material of the embodiment is different from that of the embodiment 5 in that: 160mg of vanadium pentoxide was dispersed in 10mL of deionized water, which was otherwise the same as in example 5 and will not be described again.

The capacity retention rate of the bismuth ion doped vanadium oxide material of the embodiment can reach 83% after 100 cycles at 0.1A/g, and the electrochemical performance is excellent.

Example 8

The preparation method of the bismuth ion doped vanadium oxide material of the embodiment is different from that of the embodiment 5 in that: 320mg of vanadium pentoxide was dispersed in 10mL of deionized water, which was otherwise the same as in example 5 and will not be described again.

The capacity retention rate of the bismuth ion doped vanadium oxide material of the embodiment can reach 41% after 100 cycles at 0.1A/g, and the electrochemical performance is excellent.

Example 9

The preparation method of the bismuth ion doped vanadium oxide material of the embodiment is different from that of the embodiment 5 in that: 250mg of vanadium pentoxide was dispersed in 10mL of deionized water, which was otherwise the same as in example 5 and will not be described again.

The capacity retention rate of the bismuth ion doped vanadium oxide material of the embodiment can reach 47% after 100 cycles at 0.1A/g, and the electrochemical performance is excellent.

According to the embodiment, the copper ions or the bismuth ions are doped into the vanadium oxide layers, so that the distance between the vanadium oxide layers is increased, the vanadium oxide structure is stabilized, and the prepared copper ion or bismuth ion doped vanadium oxide material has good electrochemical performance. As can be seen by comparing the experimental data in the embodiment 5 and the embodiment 7-9, the capacity retention rate after the whole cycle is reduced along with the reduction of the adding amount of the vanadium pentoxide; when the addition amount of vanadium pentoxide is 160mg, the capacity retention rate is high because the discharge specific capacity is integrally low.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.