Preparation method of aqueous ion battery organic-inorganic composite positive electrode material

Abstract

The application relates to a preparation method of a water-based ionic battery organic-inorganic composite positive electrode material and belongs to the technical field of water-based ionic battery positive electrode materials. The method is characterized in that aniline and acid are added to a V2O5 aqueous solution to adjust the pH to 3-6, then a polar solvent containing Ti-MXene powder is added and uniformly mixed, and then the mixture is transferred to a high-pressure reaction kettle to react at 80-200 DEG C for 12-24 hours to obtain the water-based ionic battery organic-inorganic composite positive electrode material. The V2O5 is modified by simultaneously using polyaniline and Ti-MXene, the specific capacity, rate performance and cycle performance of the material can be improved, the in-situ synthesis process is simple in operation, the reaction conditions are controllable, the product is uniform in phase, high in purity, good in crystallization and high in yield.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a water-based ion battery organic-inorganic composite positive electrode material and belongs to the technical field of water-based ion battery positive electrode materials. BACKGROUND

[0002] Compared with traditional batteries, water-based ion batteries replace organic electrolyte with neutral or near-neutral inorganic salt aqueous solution as electrolyte, are high in safety, and are high in ion transmission rate; meanwhile, the positive electrode and the negative electrode adopt ion intercalation and deintercalation to store and release electric energy, so that the water-based ion battery has a high cycle life and is suitable for energy storage. SUMMARY

[0003] In view of the problems in the prior art, the application provides a preparation method of a water-based ion battery organic-inorganic composite positive electrode material.

[0004] The application aims to realize the following technical scheme.

[0005] A preparation method of a water-based ion battery organic-inorganic composite positive electrode material specifically comprises the following steps:

[0006] (1) V2O5 is dissolved in water with a purity not less than deionized water, then aniline is added, and an acid is added to adjust the pH of the mixed solution to 3-6 to obtain solution I;

[0007] (2) Ti-MXene powder is added into a polar solvent that is miscible with water and is uniformly ultrasonically dispersed, and then is added into solution I and is uniformly mixed to obtain solution II;

[0008] (3) Solution II is transferred into a high-pressure reaction kettle, is reacted at 80-200 DEG C for 12-24 h, and then the solid product is collected and is cleaned and dried to obtain the water-based ion battery organic-inorganic composite positive electrode material;

[0009] The mass fraction of each reaction raw material is as follows, based on the total mass of the reaction raw materials being 100%: V2O5 55-75%, aniline 20-40%, and Ti-MXene 0.6-9%.

[0010] Preferably, the acid in step (1) is hydrochloric acid, nitric acid, oxalic acid, perchloric acid, sulfuric acid, hydroiodic acid, or hydrobromic acid.

[0011] Preferably, in step (1), the concentration of V2O5 in water is 0.02-0.05 mol / L; and in step (2), the concentration of Ti-MXene in the polar solvent is 0.6-1.0 g / L.

[0012] Preferably, after adding solution I in step (2), stirring is performed at a rate of 300-400 r / min for 0.5-1 h to obtain mixed solution II.

[0013] Preferably, the polar solvent in step (2) is methanol, ethanol, propanol, butanol, or acetic acid.

[0014] Preferably, the mass fraction of polyaniline is 25%-35%, and the mass fraction of Ti-MXene is 6%-8%.

[0015] Advantages:

[0016] (1) The present application simultaneously uses polyaniline and Ti-MXene to modify V2O5, wherein polyaniline is intercalated in situ between the structure of vanadium pentoxide, widens the interlayer distance, and reduces the interlayer electrostatic interaction, which is conducive to the transmission of ions between the layers; the addition of Ti-MXene polymerization plays an important role in increasing the electrical conductivity of the material and improving the order of the micro-morphology structure of the material, which is conducive to increasing the specific capacity of the material, improving the rate performance, and improving the cycle stability, thereby obtaining an organic-inorganic composite positive electrode material with good electrochemical performance.

[0017] (2) In the preparation method of the present application, too low aniline content cannot achieve the effects of increasing the capacity and expanding the material interlayer distance, and too high aniline content increases the impedance of the material, which is not conducive to electrochemical cycling; too low Ti-MXene content has little effect on improving the electrochemical performance, and too high Ti-MXene content not only increases the cost, but also decreases the electrical conductivity, and at the same time, the electrochemical capacity, cycle stability, and rate performance of the material are also poor. Therefore, the addition amount of aniline and Ti-MXene needs to be strictly controlled.

[0018] (3) The preparation method described in this invention requires control of the system pH, reaction temperature and reaction time. If the pH of the system is too low or the alkaline environment is too alkaline, the material properties will be deactivated. The hydrothermal reaction temperature directly affects the in-situ synthesis process, and affects the intercalation process and the microstructure of the material. If the reaction temperature is too low, it will not provide the driving force required for the reaction. If the reaction temperature is too high, it will destroy the structure of the material. If the reaction time is too short, the reaction will be insufficient. If the reaction time is too long, the interlayer distance of the synthesized material will be too large or even the structure will collapse.

[0019] (4) The present invention uses hydrothermal reaction for in-situ synthesis of materials. The process is simple and the reaction is more complete due to the thorough mixing of the materials during the reaction. The temperature, pressure and reaction time of the reaction process are controllable. The product has uniform phase, high purity, good crystallization and high yield. The hydrothermal synthesis process is carried out under closed conditions to minimize environmental pollution. Attached Figure Description

[0020] Figure 1 The image shows a scanning electron microscope (SEM) image of the PVM cathode material prepared in Example 1.

[0021] Figure 2 This is a scanning electron microscope image of pure V2O5.

[0022] Figure 3 The image shows a scanning electron microscope image of the PV cathode material prepared for Comparative Example 1.

[0023] Figure 4 Scanning electron microscope image of the VM cathode material prepared for Comparative Example 2.

[0024] Figure 5 The image shows a scanning electron microscope image of the PVM cathode material prepared in Example 2.

[0025] Figure 6 The image shows a scanning electron microscope image of the PVM cathode material prepared in Example 3.

[0026] Figure 7 The image shows a scanning electron microscope image of the PVM cathode material prepared in Example 4.

[0027] Figure 8 Comparison of scanning electron microscope images of the PVM cathode materials prepared in Examples 1, 5-7.

[0028] Figure 9 Comparison of X-ray diffraction (XRD) images of the cathode materials prepared in Examples 1-4 and Comparative Example 1, and pure V2O5.

[0029] Figure 10The X-ray diffraction comparison diagrams of VM cathode materials and pure V2O5 obtained by using different contents of Ti-Mxene to modify V2O5 in Comparative Example 2 are shown.

[0030] Figure 11 The CV curves of the button cell assembled from the PVM cathode material prepared in Example 1 at different scan rates are shown.

[0031] Figure 12 The CV curve of the PV cathode material prepared for Comparative Example 1 was obtained by assembling a coin cell at a scan rate of 1 mV / s.

[0032] Figure 13 Comparison of CV curves of button cells assembled from the cathode materials prepared in Examples 1, 3, 4, and 9 and Comparative Examples 1-2 at a scan rate of 0.1 mV / s during the first week.

[0033] Figure 14 The impedance (EIS) test comparison diagrams are shown for the cathode materials prepared in Examples 1-4, Example 9, and Comparative Example 1.

[0034] Figure 15 The impedance (EIS) test comparison diagrams are shown for the cathode materials prepared in Examples 1, 5-8.

[0035] Figure 16 The graphs show a comparison of the rate performance of button batteries made from cathode materials prepared using Example 1 and Comparative Examples 1-2, as well as those made from pure V2O5.

[0036] Figure 17 These are long-cycle comparison graphs of the cathode materials prepared using Examples 1, 2, 5 and Comparative Examples 1-2, respectively, and the button batteries assembled using pure V2O5.

[0037] Figure 18 The image shows a mapping diagram of the PVM cathode material prepared in Example 1. Detailed Implementation

[0038] The present invention will be further described below with reference to specific embodiments. Unless otherwise specified, the methods described are conventional methods, and the raw materials described are obtainable from publicly available commercial sources.

[0039] Example 1

[0040] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 100μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0041] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 315 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0042] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0043] Figure 9 The phase analysis results showed that, compared with the unmodified orthogonal V2O5 (JCPDS card number; 41-1426) modified with polyaniline and Ti-Mxene in Example 1, a large number of diffraction peaks disappeared. The strongest peak value was that the (001) plane of V2O5 shifted from 20.3° to 6.2°, the lattice spacing increased, and there was a tendency for new peaks to form about 5° to the left of the (001) plane.

[0044] Figure 1 and Figure 2 The microstructure characterization results showed that the V2O5 modified with polyaniline and Ti-Mxene in Example 1 had a dense lamellar structure, while the unmodified orthogonal V2O5 had a smooth block structure.

[0045] The organic-inorganic composite cathode material of the aqueous ion battery prepared in Example 1 was used as the cathode for assembling 2032 button cells. Zinc foil was used as the anode, glass fiber was used as the separator, and 150 μL of 3M zinc trifluoromethanesulfonate solution was used as the electrolyte (the assembly steps of the button cells in the following examples and comparative examples are the same).

[0046] The assembled button cells were subjected to CV testing on a CHI electrochemical workstation. The test voltage ranged from 0.4 to 1.4 V, and the scan rates were set to 0.1 mV / s, 0.3 mV / s, 0.5 mV / s, 0.7 mV / s, 0.9 mV / s, and 1.0 mV / s, respectively. Figure 11 The test results show that the CV curve of the button cell has two sets of redox peaks. As the scan speed increases, the redox peaks become more obvious, indicating that the material has a large pseudocapacitive effect, which is beneficial to improving the battery capacity.

[0047] Figure 13 The CV curves from the first week of the scan show higher peak values ​​for a set of redox peaks at low potentials compared to other embodiments, and also a higher capacitance contribution rate under those conditions.

[0048] Figure 14The impedance test results show that the PVM cathode material prepared in Example 1 has the lowest resistance, about 225 ohms. Low resistance is beneficial to the transport of ions and electrons, and is beneficial to the battery cycle and capacity release.

[0049] Figure 16 The rate performance test results show that the PVM cathode material prepared in Example 1 has good rate performance at 0.1 A g. -1 Under the tested conditions, the specific capacity can reach 325mAh g. -1 At 0.2A g -1 Under the tested conditions, the specific capacity can reach 275mAh g. -1 At 0.5A g -1 Under the tested conditions, the specific capacity can reach 200 mAh g. -1 , at 1.0A g -1 Under the tested conditions, the specific capacity can still reach 100mAh g. -1 It also exhibits good reversibility and cycle stability.

[0050] Figure 17 Long-cycle data results show that the coin cell assembled using the PVM cathode material prepared in Example 1 has a capacity of approximately 350 mAh g. -1 It has an ultra-high specific capacity and a certain degree of stability compared to other embodiments. After 45 cycles, the capacity retention rate is about 100%.

[0051] Figure 18 The mapping test results showed that polyaniline, V2O5 and Ti-Mxene underwent uniform intercalation polymerization.

[0052] Example 2

[0053] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 100μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0054] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 45 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0055] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0056] Figure 9 The phase analysis results showed that, compared with the unmodified orthogonal V2O5 (JCPDS card number; 41-1426) modified with polyaniline and Ti-Mxene in Example 2, a large number of diffraction peaks disappeared. The strongest peak value was that the (001) plane of V2O5 shifted from 20.3° to 6.2°, the lattice spacing increased, and the tendency for new peaks to form about 5° to the left of the (001) plane was smaller than that in Example 1.

[0057] Figure 5 The microstructure characterization results show that the V2O5 modified with polyaniline and Ti-Mxene in Example 2 initially has a lamellar morphology, but the structural arrangement is relatively irregular.

[0058] A coin cell was assembled using the PVM cathode material obtained in Example 2, and its electrochemical performance was tested. CV test results showed that the coin cell had a low redox peak, a low capacity contribution rate, and a small electrochemical window. Rate performance test results showed that the coin cell achieved a rate of 0.1 A g... -1 Under the test conditions, the specific capacity was only 220mAh g. -1 At high current 1.0A g -1 Under the test conditions, the specific capacity is approximately 75 mAh g. -1 .

[0059] Figure 14 The impedance test results show that its reactive impedance is approximately 375 ohms.

[0060] Figure 17 The long-cycle data graph shows that its initial specific capacity can reach 300mAh g. -1 After 100 cycles, the capacity is less than 50% of its initial capacity, and after 430 cycles, the specific capacity is 75 mAh g. -1 At this point, the capacity retention rate is 25%.

[0061] Example 3

[0062] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 100μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0063] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 135 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0064] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0065] Figure 9 The phase analysis results showed that, compared with the unmodified orthogonal V2O5 (JCPDS card number; 41-1426) modified with polyaniline and Ti-Mxene in Example 3, a large number of diffraction peaks disappeared. The strongest peak value was that the (001) plane of V2O5 shifted from 20.3° to 6.2°, the lattice spacing increased, and there was a tendency for new peaks to form about 5° to the left of the (001) plane, which was greater than that in Example 1 but greater than that in Example 2.

[0066] Figure 6 The microstructure characterization results showed that the V2O5 modified with polyaniline and Ti-Mxene in Example 3 exhibited a flower cluster structure with a relatively irregular arrangement.

[0067] according to Figure 13 The CV test results show that, compared with Example 1, the redox site voltage of the cathode material prepared in Example 3 decreased and increased, respectively, that is, the electrochemical window decreased.

[0068] Figure 14 The impedance test results show that its reactive impedance is 500 ohms.

[0069] Figure 13 The CV test results showed that the redox peak was small in the first week, the capacitance contribution rate was low, and the potential difference between the oxidation and reduction peaks was small, indicating that the electrochemical window was small.

[0070] According to the test results of its rate performance, it is known to be effective at 0.1A g. -1 Under the test conditions, the specific capacity is 230mAh g. -1 At high current 1.0A g -1 Under the test conditions, the specific capacity is 60mAh g. -1 Then reduce the test current to 0.1A g. -1 Its specific capacity can still reach 230mAh g. -1 This indicates that it has relatively good rate performance. According to the long-cycle test results, its initial specific capacity is 280 mAh g. -1 After 200 cycles, the specific capacity decreased to 100 mAh g. -1 The capacity retention rate was 35.7%.

[0071] Example 4

[0072] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 100μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0073] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 225 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0074] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0075] Figure 9 The phase analysis results showed that, compared with the unmodified orthogonal V2O5 (JCPDS card number; 41-1426) modified with polyaniline and Ti-Mxene in Example 4, a large number of diffraction peaks disappeared. The strongest peak value was that the (001) plane of V2O5 shifted from 20.3° to 6.2°, the lattice spacing increased, and there was a tendency for new peaks to form about 5° to the left of the (001) plane, which was smaller than that in Example 1, but larger than that in Example 2 and Example 3.

[0076] Figure 7 The microstructure characterization results show that the V2O5 modified with polyaniline and Ti-Mxene in Example 4 has a lamellar morphology and a relatively regular structural arrangement.

[0077] Figure 13 The CV test results show that its redox peak is lower than that of Example 1, and its capacitance contribution rate is lower than that of Example 1.

[0078] Figure 14 The impedance test results showed that its reactive resistance reached 460 ohms, which was higher than 225 ohms in Example 1 and lower than 500 ohms in Example 3, indicating that increasing the amount of Ti-Mxene added within a certain range is beneficial to reducing the initial impedance.

[0079] According to the test results of its rate performance, it is known to be effective at 0.1A g. -1 Under the test conditions, the specific capacity is 250mAh g. -1 At high current 1.0A g -1 Under the test conditions, the specific capacity is 75mAh g. -1 According to the cycle performance test results, its initial specific capacity is 220 mAh g. -1After 200 cycles, the specific capacity decreased to 60 mAh g. -1 The capacity retention rate was 27.3%.

[0080] Example 5

[0081] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 60μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0082] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 315 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0083] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0084] Figure 8 The microstructure characterization results show that the V2O5 modified with polyaniline and Ti-Mxene in Example 5 does not have a distinct layered structure.

[0085] according to Figure 15 The impedance test results show that the impedance of the button cell assembled using the positive electrode material prepared in Example 5 is greater than that in Example 1.

[0086] A button cell was assembled using the cathode material prepared in Example 5. The CV test results showed that the cell had a small electrochemical window and a low redox peak, indicating a low contribution rate to the capacitance. Rate performance tests showed that it performed well at a low current of 0.1 A g. -1 The specific capacity is 190mAh g. -1 At high current 1.0A g -1 The specific capacity is 50mAh g. -1 ; Figure 17 Long-cycle testing results show that its initial capacity is 225mAh g. -1 The specific capacity after 100 cycles is 125 mAh g. -1 The capacity retention rate was 55.6%.

[0087] Example 6

[0088] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 80μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0089] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 315 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0090] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0091] Figure 8 The microstructure characterization results show that the V2O5 modified with polyaniline and Ti-Mxene in Example 6 does not have a distinct layered structure.

[0092] according to Figure 15 The impedance test results show that the impedance of the button cell assembled using the positive electrode material prepared in Example 6 is greater than that of Example 1 and Example 5.

[0093] A button cell was assembled using the cathode material prepared in Example 6. The CV test results showed that its electrochemical window was smaller than that of Example 1, and the peak value of the redox peak was lower, indicating a lower contribution rate to the capacitance. Rate performance test results showed that it performed well at a low current of 0.1 A g. -1 The specific capacity is 200mAh g. -1 At high current 1.0A g -1 The specific capacity is 70mAh g. -1 Long-cycle testing results show that its initial capacity is 230mAh g. -1 After 100 cycles, the specific capacity is 130 mAh g. -1 The capacity retention rate was 56.5%.

[0094] Example 7

[0095] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 120μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0096] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 315 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0097] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0098] Figure 8 The microstructure characterization results show that the V2O5 modified with polyaniline and Ti-Mxene in Example 7 does not have a distinct layered structure.

[0099] according to Figure 15 The impedance test results show that the impedance of the button cell assembled using the positive electrode material prepared in Example 7 is comparable to that of Example 1 and Example 5, but smaller than that of Example 6.

[0100] A button cell was assembled using the cathode material prepared in Example 7. The CV test results showed that its electrochemical window was smaller than that of Example 1, and the peak value of the redox peak was lower, indicating a lower contribution rate to the capacitance. Rate performance test results showed that it performed well at a low current of 0.1 A g. -1 The specific capacity is 250mAh g. -1 At high current 1.0A g -1 The specific capacity is 90mAh g. -1 Long-cycle testing results show that its initial capacity is 270mAh g. -1 After 100 cycles, the specific capacity is 140 mAh g. -1 The capacity retention rate was 52%.

[0101] Example 8

[0102] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 140μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0103] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 315 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0104] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0105] According to the microstructure characterization results, the V2O5 modified with polyaniline and Ti-Mxene in Example 8 does not have an obvious layered structure.

[0106] according to Figure 15 The impedance test results show that the impedance of the button cell assembled using the positive electrode material prepared in Example 8 is comparable to that of Examples 1, 5 and 7, but smaller than that of Example 6.

[0107] A button cell was assembled using the cathode material prepared in Example 8. The CV test results showed that its electrochemical window was smaller than that of Example 1, and the peak value of the redox peak was lower, indicating a lower contribution rate to the capacitance. Rate performance test results showed that it performed well at a low current of 0.1 A g. -1 The specific capacity is 280mAh g. -1 At high current 1.0A g -1 The specific capacity is 90mAh g. -1 Long-cycle testing results show that the capacity increases in the first 5 weeks, reaching a specific capacity of 300mAh g. -1 The capacity decay rate is lower than that of Example 1, but higher than that of Examples 5-7, and the capacity decay rate is slower than that of Examples 5-7, decreasing to 66% of the initial capacity after 100 cycles.

[0108] Example 9

[0109] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 100μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0110] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 405 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0111] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0112] According to the phase analysis results, compared with the unmodified orthorhombic V2O5 precursor (JCPDS card number: 41-1426), the V2O5 modified with polyaniline and Ti-Mxene showed a significant disappearance of diffraction peaks. The strongest peak value shifted from 20.3° to 6.2° on the (001) plane of V2O5, indicating an increase in lattice spacing. Furthermore, a new peak tended to form approximately 5° to the left of the (001) plane. Additionally, as the Ti-Mxene content gradually increased, the peak value on the (007) plane of PVM decreased slightly compared to that of PV.

[0113] According to the microstructure characterization results, the V2O5 modified with polyaniline and Ti-Mxene in Example 9 is in the form of dense lamellar structure.

[0114] Figure 13 The CV test results showed that its redox potential was almost identical to that of Example 1, but the peak value of its redox peak was slightly lower than that of Example 1.

[0115] Figure 14 The impedance test diagram shows that its reactive resistance is 250 ohms.

[0116] According to the rate performance test results, it is known that at 0.1A g -1 Under the test conditions, the specific capacity is 230mAh g. -1 At 0.2A g -1 Under the test conditions, the specific capacity is 175mAh g. -1 At 0.5A g -1 Under the test conditions, the specific capacity is 150mAhg -1 , at 1.0A g -1 Under the test conditions, the specific capacity is 75mAh g. -1 According to the long-cycle test results, its initial specific capacity is 225 mAh g. -1 The capacity subsequently decreased, and after 100 cycles, the specific capacity dropped to 130 mAh g. -1 The specific capacity and cycle stability are reduced compared to Example 1.

[0117] Comparative Example 1

[0118] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 100μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0119] (2) Transfer solution I to a high-pressure reactor lined with Teflon and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times each with deionized water and ethanol, and dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PV cathode material.

[0120] Figure 3 The microstructure characterization results showed that the polyaniline-modified V2O5 in Comparative Example 1 had a more obvious sheet-like structure, but it was disordered and had no obvious arrangement pattern.

[0121] Figure 9 The phase analysis results showed that, compared with the unmodified orthorhombic V2O5 (JCPDS card number; 41-1426) modified with polyaniline in Comparative Example 1, a large number of diffraction peaks disappeared. The strongest peak was the (001) plane of V2O5, which shifted from 20.3° to 6.2°, and the lattice spacing increased. However, no new peaks were formed about 5° to the left of the (001) plane.

[0122] Figure 12 The organic-inorganic composite cathode material for aqueous ion batteries prepared for Comparative Example 1 was tested at 1 mV s. -1 The CV test results for the first three weeks at the specified scan rate show that the peak potential of the oxidation peak in the first week is larger than that in the following two weeks, indicating that the electrode material was activated in the first week. The CV curves for the following two weeks show good agreement, within the range of 0.6-0.8V (vs Zn). 2+ The vertical current value at / Zn) is larger in the third week than in the second week, indicating that the electrochemical resistance decreases slightly as the cycle progresses, which is beneficial to the electrochemical cycle.

[0123] Figure 13 The CV curve test plot shows that it has a pair of redox peaks located at 1.08V and 0.85V respectively.

[0124] Figure 14 The impedance test diagram shows that its reactive resistance is approximately 525 ohms, which is larger than the 225 ohms of Example 1.

[0125] Figure 16 The rate performance test results show that it performs well at 0.1A g. -1 Under the test conditions, the specific capacity is 230mAh g. -1 Furthermore, within 10 cycles, a jump point phenomenon occurred, indicating capacity instability. At 0.2A g... -1 Under the test conditions, the specific capacity is 175mAh g. -1 At 0.5A g -1 Under the test conditions, the specific capacity is 100mAh g. -1 , at 1.0A g -1 Under the test conditions, the specific capacity is 50mAh g. -1 Subsequently, the test current was gradually reduced, and it was found that 0.5A g -1 Under the test conditions, the specific capacity is 100mAh g. -1 At 0.2A g -1Under the test conditions, the specific capacity is 150mAh g. -1 0.1A g -1 Under the test conditions, the specific capacity is approximately 140 mAh g. -1 It was found that the capacity of the two pairs under the same current was significantly different, and the cycle stability and reversibility were poor.

[0126] Figure 17 Cyclic test results showed that its capacity increased in the first five weeks, with the specific capacity increasing from the initial 200 mAh g. -1 Upgraded to 250mAh g -1 Subsequently, the capacity continued to decline, and after 40 cycles, the specific capacity decreased to 150 mAh g. -1 The subsequent loop is unstable, and the long loop data graph shows random points, indicating poor loop stability.

[0127] Comparative Example 2

[0128] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, and then add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0129] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 315 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0130] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 100°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain an organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as VM cathode material. At this time, the amount of Ti-MXene added is 7%.

[0131] Based on Comparative Example 2, the volume of step (2) added to solution I was changed from 315 μL to 225 μL, while other steps and conditions remained unchanged, resulting in a VM cathode material with a Ti-Mxene addition of 5%.

[0132] Figure 10 Phase analysis results show that VM is related to orthogonal V2O , (JCPDS card number; 41-1426) Compared with the previous one, a large number of diffraction peaks disappeared, and there was a tendency for new peaks to form about 5° to the left of the (001) plane. Furthermore, the (004) plane shifted slightly to the left as Ti-Mxene increased.

[0133] Figure 4 The microstructure characterization results showed that the morphology of Ti-Mxene with only 7% added was not layered and had no obvious characteristics.

[0134] Figure 13 The CV curve test results show that when the Ti-MXene addition amount is 7%, its redox peak value is smaller and has two sets of redox peaks. Compared with Example 1, its peak position shifts towards the high voltage direction.

[0135] Figure 16 The rate performance test results show that when the Ti-MXene addition amount is 7%, it achieves a rate performance of 0.1A g. -1 Under the test conditions, the specific capacity is 200mAh g. -1 At 0.2A g -1 Under the test conditions, the specific capacity is 175mAh g. -1 At 0.5A g -1 Under the test conditions, the specific capacity is 125mAh g. -1 , at 1.0A g -1 Under the test conditions, the specific capacity is 100mAh g. -1 .

[0136] Figure 17 The long-cycle test results show that with a Ti-MXene addition of 7%, the initial specific capacity is 225 mAh g. -1 The capacity showed a slight increasing trend afterward, and the specific capacity remained basically at 230mAh g after 70 cycles. -1 about.

[0137] Comparative Example 3

[0138] (1) Dissolve 0.18g V2O5 in 30mL of ultrapure water, stir well, then add 100μL of aniline and add hydrochloric acid to adjust the pH of the mixed solution to 3-3.5 to obtain solution I;

[0139] (2) Add 400 mg Ti-MXene powder to 5 mL of ethanol and disperse it evenly by ultrasonication. Then take 585 μL and add it to solution I. Stir at 300 r / min for 1 h to obtain solution II.

[0140] (3) Transfer solution II to a Teflon-lined high-pressure reactor and react at 140°C for 24 hours. Collect the solid product by centrifugation, then wash it three times with deionized water and three times with ethanol, and then dry it in a 60°C oven to obtain the organic-inorganic composite cathode material for aqueous ion batteries, abbreviated as PVM cathode material.

[0141] According to the phase analysis results, compared with the unmodified orthorhombic V2O5 precursor (JCPDS card number: 41-1426), the V2O5 modified with polyaniline and Ti-Mxene showed a significant disappearance of diffraction peaks. The strongest peak value shifted from 20.3° to 6.2° on the (001) plane of V2O5, indicating an increase in lattice spacing. Furthermore, there was a tendency for new peaks to form approximately 5° to the left of the (001) plane. Additionally, the peak value on the (007) plane of PVM was smaller than that of PV.

[0142] According to the microscopic morphology characterization results, the V2O5 modified with polyaniline and Ti-Mxene in Comparative Example 3 is a dense lamellar structure, but its arrangement structure is somewhat disordered and some structures have collapsed.

[0143] The CV test results showed that the redox potential difference was reduced, the electrochemical window was smaller than that of Example 1, and the peak value of the redox peak was lower than that of Example 1.

[0144] Impedance test results show that its reactive resistance is 2000 ohms.

[0145] According to the rate performance test results, it is known that at 0.1A g -1 Under the test conditions, the specific capacity is approximately 150 mAh g. -1 At 0.2A g -1 Under the test conditions, the specific capacity is 90mAh g. -1 At 0.5A g -1 Under the test conditions, the specific capacity is 75mAhg. -1 , at 1.0A g -1 Under the test conditions, the specific capacity is less than 50mAh g. -1 Furthermore, when the current density was subsequently reduced, the specific capacity exhibited before and after the test at the same current density was not entirely consistent, indicating poor rate performance of the material. According to long-cycle testing results, its initial specific capacity was 150 mAh g⁻¹. -1 Subsequently, the capacity rapidly decayed, and after 50 cycles, the specific capacity decreased to 10 mAh g. -1 The specific capacity and cycle stability were reduced compared to Example 1, and random spots appeared.

[0146] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an organic-inorganic composite cathode material for an aqueous ion battery, characterized in that: Specifically, the following steps are included: (1) Dissolve V2O5 in water with a purity not less than that of deionized water, then add aniline and add acid to adjust the pH of the mixed solution to 3-6 to obtain solution I; (2) Add Ti-MXene powder to a polar solvent that is miscible with water and disperse it evenly by ultrasonication. Then add it to solution I and mix it evenly to obtain solution II. (3) Transfer solution II to a high-pressure reactor and react at 80-200℃ for 12-24 hours. Collect the solid product and clean and dry it to obtain the organic-inorganic composite cathode material for aqueous ion batteries. With the total mass of the reaction raw materials as 100%, the mass fractions of each reaction raw material are as follows: V2O5 55-75%, aniline 20-40%, and Ti-MXene 0.6-9%.

2. The method for preparing an organic-inorganic composite cathode material for an aqueous ion battery according to claim 1, characterized in that: The acid in step (1) is hydrochloric acid, nitric acid, oxalic acid, perchloric acid, sulfuric acid, hydroiodic acid, or hydrobromic acid.

3. The method for preparing an organic-inorganic composite cathode material for an aqueous ion battery according to claim 1, characterized in that: In step (1), the concentration of V2O5 in water is 0.02 to 0.05 mol / L; in step (2), the concentration of Ti-MXene in a polar solvent is 0.6 to 1.0 g / L.

4. The method for preparing an organic-inorganic composite cathode material for an aqueous ion battery according to claim 1, characterized in that: After adding solution I in step (2), stir at a rate of 300-400 r / min for 0.5-1 h to obtain mixed solution II.

5. The method for preparing an organic-inorganic composite cathode material for an aqueous ion battery according to claim 1, characterized in that: The polar solvent in step (2) is methanol, ethanol, propanol, butanol or acetic acid.

6. A method for preparing an organic-inorganic composite cathode material for an aqueous ion battery according to any one of claims 1 to 5, characterized in that: The mass fraction of polyaniline is 25%–35%, and the mass fraction of Ti-MXene is 6%–8%.

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