Modified zinc electrode material and preparation method and application thereof

Abstract

The invention discloses a modified zinc electrode material as well as a preparation method and application thereof, 3, 4-ethylenedioxythiophene, lauryl sodium sulfate and potassium perchlorate are taken as electrolyte, and the surface of a zinc electrode is coated with an organic polymer coating in an electrochemical polymerization manner, so that the problems of dendritic crystal growth, side reaction, corrosion and the like of the zinc electrode are solved; the cycling stability and reversibility of the zinc electrode are improved; meanwhile, the coating has hydrophilicity and better electrolyte wetting capacity, zinc ions are helped to be rapidly diffused on an electrode, and the polarization influence caused by concentration difference in the cycle process of the battery is relieved. Besides, by controlling the electrochemical polymerization time, the thickness of the coating is controlled, and the method has the advantages of simplicity, rapidness and the like and is suitable for large-scale popularization and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of negative electrode material preparation, and in particular relates to a modified zinc electrode material and a preparation method and application thereof. Background Art

[0002] Zinc-based batteries have the advantages of safety, reliability, abundant resources, environmental friendliness, and low cost. They also have the characteristics of high theoretical energy density and are a new type of energy storage battery with great development potential. When zinc metal is used as an electrode, it is easy to lose two electrons to become zinc ions, and multi-electron reactions occur in the battery. It is a metal with a high theoretical capacity (820mAh g -1 With 5855 mAh L -1 ), these advantages make zinc metal one of the most promising electrode materials. However, in neutral or mildly acidic electrolytes, the formation and growth of dendrites is a terrible problem. Severe dendrite growth can lead to puncturing the separator, which will reduce battery performance and even cause battery short circuit in severe cases. Moreover, due to the zinc metal negative electrode Zn 2+ / The standard redox potential of Zn is -0.76 V (vs. SHE), which makes it inevitable for zinc metal to undergo a hydrogen evolution side reaction (HER) in aqueous electrolytes. The flammable H2 gas produced by HER increases the internal pressure of the battery, eventually causing the battery to swell or even explode. These problems reduce the performance of zinc-based batteries and seriously hinder their commercialization.

[0003] At present, in order to solve the problems of zinc electrode dendrite growth, side reactions and corrosion, many methods and strategies have been proposed to improve the cycle stability and life of zinc anode, such as electrolyte modification, electrode 3D and alloying, diaphragm modification, electrode interface coating modification, etc. Among them, the simplest, most direct and effective method is electrode interface coating modification. In recent years, many coatings have been applied to the surface of zinc electrodes, all of which have played a good role, including inorganic salts, metals, oxides, organic polymers and other materials.

[0004] Chinese patent CN111162260 A discloses a conductive polymer-coated composite zinc negative electrode and a preparation method thereof, wherein a conductive polymer is coated on a traditional zinc negative electrode by electrochemical polymerization or chemical polymerization to obtain a negative electrode material for an aqueous zinc ion battery - a composite zinc negative electrode, which inhibits the formation of dendrites in the previous zinc negative electrode during the charge and discharge process, prolongs the service life of the aqueous zinc ion battery, and improves the electrochemical performance of the aqueous zinc ion battery.

[0005] Chinese patent CN114094035B discloses a method for preparing a high cycle stability secondary zinc battery negative electrode aluminum-zinc alloy coating. By using magnetron co-sputtering technology, an aluminum-zinc alloy coating containing different metal component ratios is deposited on a zinc electrode substrate to obtain a high cycle stability secondary zinc battery negative electrode aluminum-zinc alloy coating; when the aluminum content of the aluminum-zinc coating is 30%, the obtained aluminum-zinc coated zinc negative electrode has a long cycle life of more than 4000h under the test conditions of 1mA cm-2, 1mAh cm-2.

[0006] Chinese patent CN110416549B discloses a metal zinc negative electrode with a uniform mesoporous structure coating, and its preparation method and application, including a zinc negative electrode and a clay slurry layer, which is prepared by pre-embedded zinc treatment. The raw material powder of the clay slurry includes: polyvinylidene fluoride and clay material, which can isolate the direct contact between the zinc negative electrode and the electrolyte to a certain extent, reduce the side reaction between the electrode and the electrolyte, and improve the cycle stability; at the same time, the layered porous properties of the material itself can effectively prevent the generation of dendrites piercing the diaphragm during the cycle, alleviate the volume expansion of the negative electrode, effectively reduce the occurrence of battery short circuit, and improve safety performance.

[0007] However, some coatings have poor electrical conductivity, which inevitably increases the internal resistance of the battery, affects the cycle performance of the battery, etc. Moreover, the introduction of the coating will affect the zinc ion flux of the electrode, inevitably hindering the diffusion of zinc ions from the electrolyte to the zinc substrate, and these coatings will reduce the cycle capacity of the battery and increase the polarization of the battery. In addition, many coatings are hydrophobic, although they can block the contact between the electrolyte and zinc, but the hydrophobic coating causes the electrolyte to need a long time to soak the electrode when contacting the electrode, thereby affecting the diffusion efficiency of the ions and even the charge and discharge performance. Therefore, it is necessary to prepare a zinc electrode that can solve the problems of zinc electrode dendrite growth, side reactions and corrosion, and also has good affinity and good electrochemical performance. Summary of the invention

[0008] In response to the above technical problems, the present invention provides a modified zinc electrode material, a preparation method and an application thereof, wherein a layer of PEDOT coating with hydrophilic properties is coated on the zinc negative electrode material by electrochemical polymerization, thereby inhibiting dendrite growth and side reactions, and improving the reversibility and stability of the electrode without affecting the zinc ion flux of the electrode.

[0009] In order to achieve the above object, the present invention provides a modified zinc electrode material, which adopts electrochemical polymerization to coat the zinc negative electrode material with a PEDOT coating; the coating thickness is 30-65 μm.

[0010] The present invention also provides a method for preparing a modified zinc electrode material, comprising the following steps: (1) Cleaning of negative electrode materials: ultrasonically clean the zinc negative electrode materials in an organic solvent; (2) Preparation of electrolyte: 3,4-ethylenedioxythiophene, sodium dodecyl sulfate and potassium perchlorate are placed in a solvent and mixed to prepare an electrolyte; (3) The zinc negative electrode material obtained in step (1) is used as a working electrode, a three-electrode system is adopted, and a modified zinc electrode material is obtained by electrochemical polymerization and drying.

[0011] Preferably, the organic solvent in step (1) is ethanol, with a mass percentage of ≥95%.

[0012] Preferably, in step (2), the molar ratio of 3,4-ethylenedioxythiophene, sodium dodecyl sulfate and potassium perchlorate is 0.5:5:3-5:5:3.

[0013] Further preferably, the molar ratio of 3,4-ethylenedioxythiophene, sodium dodecyl sulfate and potassium perchlorate is 1:5:3.

[0014] Preferably, the amount of the solvent used in step (2) is 15-20 times the sum of the masses of 3,4-ethylenedioxythiophene, sodium dodecyl sulfate and potassium perchlorate.

[0015] Preferably, before the electrochemical polymerization in step (3), one side of the zinc negative electrode material is coated, and after the electrochemical polymerization is completed, the coating is removed to achieve single-sided electrochemical polymerization.

[0016] Further preferably, the coating is an electrical insulating tape.

[0017] Preferably, the electrochemical polymerization conditions in step (3) are a voltage of 1.0-1.5 V and a time of 100-500 s.

[0018] Preferably, in the three-electrode system described in step (3), the counter electrode is Pt and the reference electrode is Ag / AgCl.

[0019] Preferably, the drying condition is drying at 50-70° C. for 3-5 hours.

[0020] The present invention also provides an application of the modified zinc electrode material, wherein the modified zinc electrode material is used as a negative electrode material in an aqueous zinc ion battery.

[0021] The beneficial effects of the present invention are: 1. A hydrophilic PEDOT coating was prepared on the surface of the zinc electrode using 3,4-ethylenedioxythiophene, sodium dodecyl sulfate and potassium perchlorate. While protecting the zinc electrode, it inhibited the growth of dendrites and the production of side reaction products and improved the reversibility and stability of the electrode without affecting the zinc ion flux of the electrode.

[0022] 2. The PEDOT coating enhances the desolvation ability of zinc ions, improves the migration ability of zinc ions, reduces the nucleation overpotential of zinc, makes the electric field on the zinc surface uniform, inhibits the occurrence of two-dimensional diffusion and tip discharge, and promotes the uniform deposition of zinc ions, thereby improving the stability and reversibility of the zinc electrode. In addition, it also improves the coulombic efficiency and cycle life of symmetric zinc ion batteries and half-cells, and increases the cycle life of aqueous zinc ion capacitors.

[0023] 3. The present invention adopts electrochemical polymerization to coat the surface of the zinc electrode, which has the advantages of simple process, short time consumption, and cheap material price. It is suitable for aqueous zinc batteries and can be promoted and applied on a large scale.

[0024] 4. Before electrochemical polymerization, one side of the zinc electrode can be selectively coated, and only the other side can be polymerized with the coating. Therefore, a modified zinc electrode material can be prepared, which has good conductivity on one side and can be in direct contact with the metal shell, and the other side can well protect the zinc electrode, avoid the formation of dendrites and side reactions, and reduce corrosion. It is suitable for button batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 PEDOT prepared in Example 2 150 Fourier transform infrared spectrum of coated zinc electrode.

[0026] Figure 2 PEDOT prepared in Example 2 150 X-ray diffraction pattern of the coated zinc electrode.

[0027] Figure 3 The SEM images of different electrodes after cycling in Example 8, a is a pure zinc electrode, b is a PEDOT 150 Coated zinc electrode.

[0028] Figure 4 2 is the XRD diagram of different electrodes in Example 9.

[0029] Figure 5 This is a graph showing the Tafel polarization test results of different electrodes in Example 10.

[0030] Figure 6 The different electrodes in Example 11 at 0.5 mA cm -2 and 0.25 mAh cm -2 Symmetric cycle performance diagram below.

[0031] Figure 7 The different electrodes in Example 11 at 5 mA cm -2 and 2.5 mAh cm -2Symmetric cycle performance diagram below.

[0032] Figure 8 The different electrodes in Example 12 at 2 A g -1 The cycle performance diagram below.

[0033] Fig. 9 The different electrodes in Example 12 at 10 A g -1 The cycle performance diagram below.

[0034] Fig.10 This is a nucleation overpotential test diagram of different electrodes in Example 13.

[0035] Fig.11 The different electrodes in Example 14 at 2 mA cm -2 and 0.5 mAh cm -2 Coulomb efficiency test diagram below.

[0036] Fig.12 3 is a contact angle test graph of different electrodes in Example 15 when they were in contact with the electrolyte for 0 s, in which a is the electrode prepared in Example 6, b is the electrode prepared in Example 2, c is the electrode prepared in Example 7, d is a pure zinc electrode, e is the electrode prepared in Comparative Example 4, f is the electrode prepared in Comparative Example 1, g is the electrode prepared in Comparative Example 3, and h is the electrode prepared in Comparative Example 2.

[0037] Fig.13 For pure zinc electrode and PEDOT 150 Contact angle test diagram of coated zinc electrode under different contact time with electrolyte. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be understood as limiting the present invention. The protection scope of the present invention shall be based on the contents recorded in the claims. Any modification or replacement made by those skilled in the art to the technical solution of the present invention without creative work shall fall within the protection scope of the present invention.

[0039] Example 1 (1) Cleaning of negative electrode materials: Place the zinc foil in an ethanol solution and perform ultrasonic cleaning for 2 min to obtain a clean and tidy zinc foil. Then cut the foil into a size of 2.5 cm*2.5 cm and seal the side that does not need to be polymerized with tape. (2) Preparation of electrolyte: Accurately weigh 5.407 g of sodium dodecyl sulfate (SDS) and 1.558 g of potassium perchlorate (KClO4), disperse them in 120 ml of deionized water, then use a pipette to take 380 μL of EDOT and disperse it in the solution, mix and clarify to obtain the electrolyte; (3) Electrochemical polymerization: The zinc foil obtained in step (1) was used as a working electrode, Pt was used as a counter electrode, and Ag / AgCl was used as a reference electrode. The two electrodes were immersed in an electrolyte and polymerized at 1.2 V for 100 s to prepare a zinc electrode. (4) After the electrochemical polymerization is completed, the electrode is removed, and the impurities and easily detached PEDOT on the surface are washed off with deionized water. Then the tape is removed and dried at 60°C for 4 hours to obtain PEDOT 100 Coated zinc electrode.

[0040] Example 2 The method and steps are the same as those in Example 1, except that the polymerization time in step (3) is changed to 150 s to prepare PEDOT 150 Coated zinc electrode.

[0041] Example 3 The method and steps are the same as those in Example 1, except that the polymerization time in step (3) is changed to 250 s to prepare PEDOT 250 Coated zinc electrode.

[0042] Example 4 The method and steps are the same as those in Example 1, except that the polymerization time in step (3) is changed to 350 s to prepare PEDOT 350 Coated zinc electrode.

[0043] Example 5 The method and steps are the same as those in Example 1, except that the polymerization time in step (3) is changed to 450 s to prepare PEDOT 450 Coated zinc electrode.

[0044] Example 6 The method and steps were the same as those in Example 2, except that the amount of EDOT in step (2) was changed to 0.19 μL, so that the molar ratio of EDOT, SDS and KClO4 was 0.5:5:3, and a PEDOT-coated zinc electrode was prepared.

[0045] Example 7 The method and steps were the same as those in Example 2, except that the amount of EDOT in step (2) was changed to 1.9 mL, so that the molar ratio of EDOT, SDS and KClO4 was 5:5:3, and a PEDOT-coated zinc electrode was prepared.

[0046] Comparative Example 1 The method and steps are the same as in Example 2, except that EDOT is not used to prepare a zinc electrode.

[0047] Comparative Example 2 The method and steps are the same as those in Example 2, except that sodium dodecyl sulfate is not used to prepare a zinc electrode.

[0048] Comparative Example 3 The method and steps are the same as in Example 2, except that potassium perchlorate is not used to prepare a zinc electrode.

[0049] Comparative Example 4 The method and steps are the same as in Example 2, except that EDOT is replaced by ethylene glycol to prepare a zinc electrode.

[0050] Result detection: The zinc electrodes prepared in the above examples and comparative examples were taken, and the coating thickness was detected using a metallographic optical microscope (Table 1), and Fourier infrared spectroscopy and X-ray diffraction detection were performed.

[0051] Table 1 Coating thickness of PEDOT-coated zinc electrode

[0052] like Figure 1 As shown, PEDOT 150 The coated zinc electrode has a peak at 2920 cm -1 and 2850 cm -1 The peak at about 1630 cm is the absorption peak generated by the stretching vibration of C—H and CH2 in the PEDOT structure. -1 The peak at 1466 cm -1 The absorption peak at 1200 cm is due to the stretching vibration of the C—C single bond; -1 and 1058 cm -1 The two peaks are the absorption peaks of stretching vibration of C—O bond and C—S bond, respectively, which verifies the successful preparation of PEDOT on the zinc surface.

[0053] like Figure 2 As shown, PEDOT 150 The peaks of the coated zinc electrode at 284.6 eV, 286.0 eV, and 289.2 eV are attributed to the characteristic peaks of carbon-carbon single / double bonds, carbon-sulfur bonds, and carbon-oxygen bonds, respectively, further verifying the existence of PEDOT.

[0054] Example 8 Take the PEDOT prepared in Example 2 150 The zinc electrode obtained by coating zinc electrode and pure zinc electrode was used as negative electrode, activated carbon was used as positive electrode, glass fiber was used as separator, and ZnSO4 aqueous solution was used as electrolyte to form an aqueous zinc ion battery. -1The SEM image of the zinc electrode was detected after 1800 cycles. Figure 3 As shown in the figure, after cycling, there are many disordered and large dendrites growing on the surface of the pure zinc electrode, and the surface structure collapses significantly. The collapse of these structures may first occur on the cracks on the zinc foil surface; while after cycling, the PEDOT 150 The coated zinc electrode has little surface collapse and can inhibit dendrite growth to a certain extent. Example 9 Take the PEDOT prepared in Example 2 150 The coated zinc electrode, the pure zinc electrode and the zinc electrode prepared in Comparative Examples 1-4 were immersed in 2M ZnSO4 at room temperature for 7 days, and then the pure zinc and the coated zinc were subjected to XRD detection. Figure 4 As shown in the figure, after the pure zinc electrode was immersed in the electrolyte for one week, the XRD characteristic peak of the byproduct Zn4SO4(OH)6∙xH2O appeared on its surface, while PEDOT 150 No by-product was generated on the electrode surface of the coated zinc electrode, confirming that the PEDOT coating has the effect of inhibiting the generation of by-products.

[0055] Example 10 Take the PEDOT prepared in Example 2 150 The coated zinc electrode, the pure zinc electrode and the zinc electrode prepared in Comparative Examples 1-4 were subjected to Tafel polarization test, where Pt was used as the counter electrode, pure zinc or coated zinc or comparative zinc was used as the working electrode, Ag / AgCl was used as the reference electrode, and the Tafel polarization test in the Chenhua electrochemical workstation chi660d was used as the technique. Then the Tafel test results after the test were fitted to obtain the corrosion current jcorr. The results are shown in Figure 5 As shown in Figure 2, the corrosion current of the pure zinc electrode is 2.34 mA cm -2 , while PEDOT 150 The corrosion current of the coated zinc electrode was 1.66 mA cm -2 The corrosion current of the zinc electrode prepared in Comparative Example 1 was 2.95 mA cm -2 The corrosion current of the zinc electrode prepared in comparative example 2 was 2.97 mA cm -2 The corrosion current of the zinc electrode prepared in comparative example 3 was 1.86 mA cm -2 The corrosion current of the zinc electrode prepared in Comparative Example 4 was 1.88 mA cm -2 Among them, PEDOT 150The corrosion current of the coated zinc electrode is the smallest, which proves that the PEDOT coating obtained in Example 2 has the best resistance to hydrogen evolution, and the corrosion current of the zinc electrode prepared without adding EDOT and SDS during the preparation process is larger than that of pure zinc, which means that EDOT and SDS play a key role in the preparation process.

[0056] Embodiment 11 Take the PEDOT prepared in the above example 150 The zinc electrodes prepared by the coated zinc electrode and the pure zinc electrode were -2 and 0.25 mAh cm -2 Lower, 5 mA cm -2 and 2.5 mAh cm -2 Symmetric cycles were performed under the condition of 200 μm / s, in which two identical zinc foils or coated zinc foils were selected to assemble symmetrical batteries, and constant current charge and discharge tests were performed using the LAND battery test system. The results showed that PEDOT 150 The coated zinc electrode was -2 and 0.25 mAh cm -2 Under the same conditions, the polarization of 34.4 mV was stably cycled for 1250 h, while pure zinc cycled for 448 h at 95 mV. Figure 6 and Table 2). PEDOT 150 The coated zinc electrode was -2 and 2.5 mAh cm -2 Under the same conditions, the electrode was stably cycled at a polarization of 77.8 mV for 240 h, while pure zinc was cycled at a polarization of 91.8 mV for 75 h; ( Figure 7 ); indicates that PEDOT 150 The coated zinc electrode has good cycling stability, and at higher current density, its stability and reversibility are better than those of the pure zinc electrode.

[0057] Table 2 Symmetrical battery cycling performance and symmetric battery polarization potential of electrodes

[0058] Example 12 Take the PEDOT prepared in Example 2 150 The coated zinc electrode and the pure zinc electrode were used as the negative electrode, AC activated carbon was used as the positive electrode, glass fiber was used as the separator, and ZnSO4 aqueous solution was used as the electrolyte to form an aqueous zinc ion capacitor. -1 , 10g -1 The charge and discharge cycle performance was tested under the conditions of 150 The capacitor composed of the coated zinc electrode and the AC positive electrode was assembled at 2 A g -1The number of cycles under the condition of pure zinc electrode reached 40,000 times, and the capacity retention rate reached 84%, while the capacity decayed after only 1550 cycles under the condition of pure zinc electrode. Figure 8 ); indicating that the PEDOT-coated zinc anode has stable capacitor performance and excellent capacity retention. 150 The capacitor assembled with the coated zinc electrode and the AC positive electrode has a capacitance of 10 g. -1 The number of cycles under this condition reached 80,000, and the capacity retention rate was close to 100%, while the pure zinc electrode was blocked after only 28,600 cycles under this condition ( Fig. 9 ). The full battery cycle test results at both current densities show that PEDOT 150 Good cycling performance of the coated zinc electrode.

[0059] Example 13 Take the PEDOT prepared in Example 2 150 The coated zinc electrode, the pure zinc electrode and the zinc electrodes prepared in Comparative Examples 1-4 were respectively -2 The nucleation overpotential was measured under the following conditions. The results are as follows Fig.10 As shown, the nucleation overpotential of pure zinc is 72.3 mV, the nucleation overpotential of the zinc electrode prepared without EDOT is 78.0 mV (Comparative Example 1), the nucleation overpotential of the zinc electrode prepared without SDS is 69.0 mV (Comparative Example 2), the nucleation overpotential of the zinc electrode prepared without KClO4 is 74.0 mV (Comparative Example 3), the nucleation overpotential of the PEDOT-coated zinc electrode prepared by PEDOT polymerization for 150 s is 42.5 mV, and the nucleation overpotential of the PEG prepared by replacing EDOT with EG is 42.5 mV. 150 The nucleation overpotential of Zn is 68 mV (Comparative Example 4). 150 The nucleation overpotential of Zn is the smallest, which means that the hydrophilic PEDOT coating helps to reduce the nucleation energy barrier of zinc ions and improve the deposition of zinc ions. In addition, in the preparation process, if any of EDOT, SDS, and KClO4 is not added, the prepared zinc electrode is not conducive to the deposition of zinc ions. And the zinc deposition of the electropolymerized PEDOT-coated zinc electrode is better than that of the electropolymerized PEG-coated zinc electrode.

[0060] Embodiment 14 Take the PEDOT prepared in Example 2 150 The coated zinc electrode and the pure zinc electrode were used as the negative electrode, and copper was used as the positive electrode to assemble a half-cell for the coulombic efficiency test. The test method was to use a LAND test system at 2 mA cm -2 0.5 mAhcm -2 The constant current charge and discharge test was carried out under the conditions, and the results were as follows Fig.11As shown, PEDOT 150 The Coulombic efficiency of the coated zinc electrode remained stable at around 99.5% after 450 cycles, while the Coulombic efficiency of the pure zinc electrode fluctuated between 80% and 130%. The results showed that PEDOT 150 The coated zinc electrode has more stable cycle performance and more stable Coulombic efficiency, and the PEDOT 150 The modified Zn in the coated zinc electrode is deposited and then removed very thoroughly, indicating good reversibility and stability.

[0061] Embodiment 15 Take the PEDOT prepared in the above example 150 A drop of ZnSO4 aqueous solution was dropped on the surface of the coated zinc electrode, the pure zinc electrode and the zinc electrode prepared in Comparative Examples 1-4 to detect the PEDOT 150 The contact angle between the coated zinc electrode and the ZnSO4 aqueous solution. Fig.12 As shown in the figure, with the increase of the amount of PEDOT added, the contact angle of the prepared electrode gradually increases. Therefore, the prepared good electrophilic electrolyte electrode needs to be selected under the condition of a small EDOT ratio. Under the condition that other conditions are not changed, no matter which one is removed during the preparation process, the contact angle of the prepared electrode is greater than that of the PEDOT-coated electrode, indicating that each material is essential for the preparation of a PEDOT-coated zinc electrode with good electrophilic electrolyte performance, and the selected ratio is also critical, which helps the zinc ions to diffuse rapidly on the electrode and is more conducive to reducing the polarization effect caused by the concentration difference on the zinc anode surface during the cycle.

[0062] like Fig.13 As shown, at the same time, PEDOT 150 The contact angles of the coated zinc electrode with the ZnSO4 aqueous solution were significantly smaller, indicating that PEDOT 150 The coated zinc electrode has better electrolyte wetting ability, which helps zinc ions to diffuse rapidly on the electrode and is more conducive to reducing the polarization effect caused by concentration differences on the zinc anode surface during the cycle.

Claims

1. A modified zinc electrode material, Features: The zinc negative electrode material is coated with a PEDOT coating by electrochemical polymerization; the coating thickness is 30-65 μm.

2. A method for preparing the modified zinc electrode material as claimed in claim 1, Features: The steps include: (1) Cleaning of negative electrode materials: ultrasonically clean the zinc negative electrode materials in an organic solvent; (2) Preparation of electrolyte: 3,4-ethylenedioxythiophene, sodium dodecyl sulfate and potassium perchlorate are placed in a solvent and mixed to prepare an electrolyte; (3) The zinc negative electrode material obtained in step (1) is used as a working electrode, and a three-electrode system is adopted to electrochemically polymerize to obtain a modified zinc electrode material.

3. The preparation method according to claim 2, Features: The organic solvent in step (1) is ethanol, with a mass percentage of ≥95%.

4. The preparation method according to claim 2, Features: The molar ratio of 3,4-ethylenedioxythiophene, sodium dodecyl sulfate and potassium perchlorate in step (2) is 0.5:5:3-5:5:

3.

5. The preparation method according to claim 2, Features: The amount of the solvent used in step (2) is 15-20 times the sum of the masses of 3,4-ethylenedioxythiophene, sodium dodecyl sulfate and potassium perchlorate.

6. A method for preparing a modified zinc electrode material according to claim 2, Features: Before the electrochemical polymerization described in step (3), one side of the zinc negative electrode material is coated, and after the electrochemical polymerization is completed, the coating is removed to achieve single-sided electrochemical polymerization.

7. The preparation method according to claim 6, Features: The coating is an electrical insulating tape.

8. The preparation method according to claim 2, Features: The electrochemical polymerization conditions in step (3) are voltage 1.0-1.5V and time 100-500s.

9. The preparation method according to claim 2, Features: In the three-electrode system described in step (3), the counter electrode is Pt and the reference electrode is Ag / AgCl.

10. A use of the modified zinc electrode material as claimed in claim 1, Features: The application is to use the modified zinc electrode material as a negative electrode material in an aqueous zinc ion battery.

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