Preparation method and application of nanometer TPA / PEDOT composite film with uniform thickness

Abstract

The application relates to a preparation method and application of a nanoscale TPA / PEDOT composite film with uniform thickness, and belongs to the field of water-based zinc ion battery metal zinc negative electrodes. The application aims to solve the problems that the interface protection layer of the existing zinc negative electrode causes slow zinc ion transmission and poor cycle stability. The method is as follows: concentrated hydrochloric acid is added to an EDOT solution and then left standing, TPA solution is added dropwise to the surface of the solution and then left standing, APS solution is injected into the bottom of the solution and then left standing after heating, and a nanoscale TPA / PEDOT composite film with uniform thickness is obtained at the interface of air and water. The application is used for the preparation and application of the nanoscale TPA / PEDOT composite film with uniform thickness.

Description

Technical Field

[0001] This invention belongs to the field of metallic zinc anodes in aqueous zinc-ion batteries. Background Technology

[0002] Aqueous zinc-ion batteries (AZIBs) have garnered significant attention as a promising candidate battery system for future large-scale energy storage. Zinc metal anodes possess advantages such as high theoretical specific capacity (820 mAh / g), relatively low redox potential (-0.76 V vs. the standard hydrogen electrode), low cost, abundant content, and safety and environmental friendliness. However, zinc anodes in aqueous electrolytes suffer from severe corrosion, hydrogen evolution reaction, and dendrite growth due to uneven zinc deposition. Uncontrolled zinc dendrites increase zinc metal corrosion in the electrolyte and significantly reduce coulombic efficiency (CE). In severe cases, they can puncture the separator, leading to internal short circuits and drastically shortening battery life. Therefore, regulating uniform zinc deposition and effectively preventing corrosion and hydrogen evolution reactions are crucial for improving the electrochemical performance of aqueous zinc-ion batteries. To address the issues of zinc dendrites and corrosion, constructing an artificial interface protective layer to regulate zinc ion deposition behavior is an effective strategy for achieving high reversibility and utilization. Most of the artificial interface protective layers reported in current work are prepared by in-situ growth and coating methods. However, these methods can affect the transport of zinc ions, causing problems such as slow zinc ion transport, which seriously affect the polarization voltage and cycle stability of the battery. Summary of the Invention

[0003] This invention aims to address the problems of slow zinc ion transport and poor cycle stability caused by the interface protective layer of existing zinc anodes, and provides a method for preparing and applying a uniformly thick nanoscale TPA / PEDOT composite film.

[0004] A method for preparing a uniform thickness nanoscale TPA / PEDOT composite film, comprising the following steps:

[0005] 1. Add 4-amino-p-terphenyl to chloroform solution, stir to dissolve, and obtain TPA solution;

[0006] 2. Add 3,4-ethylenedioxythiophene monomer to deionized water, stir to dissolve, and obtain EDOT solution;

[0007] 3. Add ammonium persulfate to deionized water, stir to dissolve, and obtain APS solution;

[0008] 4. Add concentrated hydrochloric acid to the EDOT solution and let it stand. Then, add TPA solution to the surface of the solution and let it stand. Finally, inject APS solution into the bottom of the solution and heat and let it stand. A uniform nanoscale TPA / PEDOT composite film is obtained at the air-water interface.

[0009] The molar ratio of 3,4-ethylenedioxythiophene monomer in the EDOT solution to 4-amino-p-terphenyl in the TPA solution is 1:(0.0005-0.001); the molar ratio of 3,4-ethylenedioxythiophene monomer in the EDOT solution to ammonium persulfate in the APS solution is 1:(1-3).

[0010] The application of uniformly thick nanoscale TPA / PEDOT composite films as an interfacial protective layer for the zinc anode in aqueous zinc-ion batteries.

[0011] The beneficial effects of this invention are:

[0012] This invention discloses a method for large-area preparation of a uniformly thick nanoscale TPA / PEDOT composite film. PEDOT is used as a crosslinking agent to link TPA molecules into a nanoscale film, which is then attached to a zinc foil. The aromatic ring portion of the upper TPA layer exhibits cation-π bond interactions with zinc ions, promoting zinc ion transport. Furthermore, the hydrophobic nature of the TPA layer isolates the electrolyte from direct contact with the electrode, thus inhibiting corrosion to some extent. The lower PEDOT layer not only enhances the mechanical strength of the film but also promotes uniform zinc ion deposition. Using the zinc foil with the protective layer as the electrode and assembling a symmetrical battery, an area capacity of 1 mAh / cm² is achieved. 2 and current density of 1 mA / cm 2 At that time, the symmetrical battery can cycle stably for more than 3200 hours; when the areal capacity is 10mAh / cm² 2 and current density of 10 mA / cm 2 At this point, the zinc utilization rate reaches 62%, and the battery can cycle stably for over 280 hours. A half-cell was assembled using a titanium foil with a protective layer as the positive electrode and a zinc foil with a protective layer as the negative electrode, achieving an area capacity of 1 mAh / cm². 2 and a current density of 2 mA / cm 2 At this time, it can stably cycle for more than 3000 times, and the average coulombic efficiency is as high as 99.78%. In summary, the film prepared by this invention has excellent protective effect, and its ability to be prepared on a large scale demonstrates its commercial potential.

[0013] Instruction manual illustrations

[0014] Figure 1The image shows the TPA / PEDOT composite film prepared in Example 1 floating on the air-water interface. a is a plastic container, b is a petri dish, the black substance in b is the precipitate generated during film preparation, and c is the TPA / PEDOT composite film with a diameter of 16 cm.

[0015] Figure 2 A scanning electron microscope image of the TPA / PEDOT composite film prepared in Example 1;

[0016] Figure 3 A transmission electron microscope image of the TPA / PEDOT composite film prepared in Example 1;

[0017] Figure 4 An atomic force microscope image of the TPA / PEDOT composite film prepared in Example 1;

[0018] Figure 5 The full spectrum of XPS test results for the TPA / PEDOT composite film prepared in Example 1;

[0019] Figure 6 The fine N1s spectrum of the TPA / PEDOT composite film prepared in Example 1 is obtained from XPS testing.

[0020] Figure 7 The graph shows a comparison of the contact angle test results of zinc sulfate electrolyte with a concentration of 2 mol / L. a) is the untreated zinc sheet, and b) is the zinc negative electrode with a protective layer prepared in Example 2.

[0021] Figure 8 Example 2: Aqueous Zinc-Ion Zn||Zn Symmetric Cell at a Current Density of 1 mA / cm² 2 and a capacity of 1mAh / cm² 2 Long-cycle performance diagram under the given conditions;

[0022] Figure 9 To compare the experimental setup, an aqueous zinc-ion Zn||Zn symmetric cell was used at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm² 2 Long-cycle performance diagram under the given conditions;

[0023] Figure 10 Example 2: Aqueous Zinc-Ion Zn||Zn Symmetric Cell at a Current Density of 10 mA / cm² 2 and a capacity of 10mAh / cm² 2 Under these conditions, the cycle performance diagram shows that the zinc anode utilization rate is 62%.

[0024] Figure 11 To compare the experimental setup, an aqueous zinc-ion Zn||Zn symmetric cell was used at a current density of 10 mA / cm².2 and a capacity of 10mAh / cm² 2 Under these conditions, the cycle performance diagram shows that the zinc anode utilization rate is 62%.

[0025] Figure 12 Example 3: Aqueous Zinc-Ion Zn||Ti Half-Cell at a Current Density of 2 mA / cm² 2 and a capacity of 1mAh / cm² 2 Long-cycle performance under certain conditions;

[0026] Figure 13 To compare the two aqueous zinc-ion Zn||Ti half-cells, the current density was 2 mA / cm². 2 and a capacity of 1mAh / cm² 2 Long-cycle performance under certain conditions;

[0027] Figure 14 Example 2: Aqueous Zinc-Ion Zn||Zn Symmetric Cell at a Current Density of 1 mA / cm² 2 and a capacity of 1mAh / cm² 2 XRD pattern of zinc anode after 50 cycles under the specified conditions;

[0028] Figure 15 To compare the experimental setup, an aqueous zinc-ion Zn||Zn symmetric cell was used at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm² 2 XRD pattern of zinc anode after 50 cycles under the specified conditions;

[0029] Figure 16 Example 2: Aqueous Zinc-Ion Zn||Zn Symmetric Cell at a Current Density of 1 mA / cm² 2 and a capacity of 1mAh / cm² 2 The surface morphology of the zinc anode after 50 cycles under the given conditions;

[0030] Figure 17 To compare the experimental setup, an aqueous zinc-ion Zn||Zn symmetric cell was used at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm² 2 The surface morphology of the zinc anode after 50 cycles under the given conditions;

[0031] Figure 18 Example 3: Aqueous Zinc-Ion Zn||Ti Half-Cell at a Current Density of 2 mA / cm² 2 and a capacity of 1mAh / cm² 2 Capacity-voltage curve under the given conditions;

[0032] Figure 19To compare the aqueous zinc ion Zn||Ti half-cell in Experiment 2 at a current density of 2 mA / cm² 2 and a capacity of 1mAh / cm² 2 Capacity-voltage curve under the given conditions;

[0033] Figure 20 The images show fine Zn 2p spectra obtained by XPS analysis. 1 is ZnSO4 powder, and 2 is a mixture of protonated TPA and ZnSO4.

[0034] Figure 21 Nuclear magnetic resonance 1 H-spectrum, 1 is protonated TPA, 2 is a mixture of protonated TPA and ZnSO4. Detailed Implementation

[0035] Specific Implementation Method 1: This implementation method is a method for preparing a uniform thickness nanoscale TPA / PEDOT composite film, which is carried out according to the following steps:

[0036] 1. Add 4-amino-p-terphenyl to chloroform solution, stir to dissolve, and obtain TPA solution;

[0037] 2. Add 3,4-ethylenedioxythiophene monomer to deionized water, stir to dissolve, and obtain EDOT solution;

[0038] 3. Add ammonium persulfate to deionized water, stir to dissolve, and obtain APS solution;

[0039] 4. Add concentrated hydrochloric acid to the EDOT solution and let it stand. Then, add TPA solution to the surface of the solution and let it stand. Finally, inject APS solution into the bottom of the solution and heat and let it stand. A uniform nanoscale TPA / PEDOT composite film is obtained at the air-water interface.

[0040] The molar ratio of 3,4-ethylenedioxythiophene monomer in the EDOT solution to 4-amino-p-terphenyl in the TPA solution is 1:(0.0005-0.001); the molar ratio of 3,4-ethylenedioxythiophene monomer in the EDOT solution to ammonium persulfate in the APS solution is 1:(1-3).

[0041] This embodiment provides a bilayer nanoscale thin film capable of large-area fabrication for zinc anode protection in aqueous zinc-ion batteries. The upper 4-amino-p-terphenyl (TPA) layer exhibits cation-π bond interactions with zinc ions through its aromatic ring portion, promoting zinc ion adsorption and transport. Furthermore, the TPA layer's hydrophobicity helps inhibit corrosion to some extent. The lower PEDOT layer, acting as a crosslinking agent, not only enhances the film's mechanical strength but also promotes uniform zinc deposition. Through the synergistic effect of these two components, the problems of zinc dendrite formation and corrosion are resolved.

[0042] The beneficial effects of this embodiment are:

[0043] This embodiment discloses a large-area preparation method for a uniformly thick nanoscale TPA / PEDOT composite film. PEDOT is used as a crosslinking agent to link TPA molecules into a nanoscale film, which is then attached to a zinc foil. The aromatic ring portion of the upper TPA layer exhibits cation-π bond interactions with zinc ions, promoting zinc ion transport. Furthermore, the hydrophobic nature of the TPA layer isolates the electrolyte from direct contact with the electrode, thus inhibiting corrosion to some extent. The lower PEDOT layer not only enhances the mechanical strength of the film but also promotes uniform zinc ion deposition. Using the zinc foil with the protective layer as the electrode and assembling a symmetrical battery, an area capacity of 1 mAh / cm² is achieved. 2 and current density of 1 mA / cm 2 At that time, the symmetrical battery can cycle stably for more than 3200 hours; when the areal capacity is 10mAh / cm² 2 and current density of 10 mA / cm 2 At this point, the zinc utilization rate reaches 62%, and the battery can cycle stably for over 280 hours. A half-cell was assembled using a titanium foil with a protective layer as the positive electrode and a zinc foil with a protective layer as the negative electrode, achieving an area capacity of 1 mAh / cm². 2 and a current density of 2 mA / cm 2 At this time, it can stably cycle for more than 3000 times, and the average coulombic efficiency is as high as 99.78%. In summary, the film prepared by this invention has excellent protective effect, and its ability to be prepared on a large scale demonstrates its commercial potential.

[0044] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the concentration of 4-amino-p-terphenyl in the TPA solution described in step one is 1 mmol / L to 3 mmol / L. Everything else is the same as in Specific Implementation Method One.

[0045] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the concentration of 3,4-ethylenedioxythiophene monomer in the EDOT solution described in step two is 3 mmol / L to 15 mmol / L. Everything else is the same as in Specific Implementation Method One or Two.

[0046] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the concentration of ammonium persulfate in the APS solution described in step three is 0.2 mol / L to 0.5 mol / L. Everything else is the same as in Specific Implementation Methods One to Three.

[0047] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the concentration of concentrated hydrochloric acid mentioned in step four is 8 mol / L to 12 mol / L. Everything else is the same as in Specific Implementation Methods One to Four.

[0048] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the volume ratio of EDOT solution to concentrated hydrochloric acid in step four is (12-15):1. Everything else is the same as in Specific Implementation Methods One to Five.

[0049] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: in step four, concentrated hydrochloric acid is added to the EDOT solution, and the solution is allowed to stand at room temperature for 1 to 5 minutes. Everything else is the same as in Specific Implementation Methods One to Six.

[0050] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: in step four, TPA solution is added dropwise to the solution surface at a dropping rate of 4 μL / s to 6 μL / s, and the solution is allowed to stand at room temperature for 30 to 40 minutes. Everything else is the same as in Specific Implementation Methods One to Seven.

[0051] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: in step four, APS solution is injected into the bottom of the solution at an injection rate of 0.1 mL / s to 0.2 mL / s, and then heated and allowed to stand for 7 to 12 hours at a temperature of 30°C to 80°C. Everything else is the same as in Specific Implementation Methods One to Eight.

[0052] Specific Implementation Method 10: This implementation method utilizes a uniformly thick nanoscale TPA / PEDOT composite film, which serves as an interface protection layer for the zinc anode in an aqueous zinc-ion battery.

[0053] The beneficial effects of the present invention are verified using the following embodiments:

[0054] Example 1:

[0055] A method for preparing a uniform thickness nanoscale TPA / PEDOT composite film, comprising the following steps:

[0056] 1. Add 4-amino-p-terphenyl to chloroform solution, stir to dissolve, and obtain TPA solution; the concentration of 4-amino-p-terphenyl in the TPA solution is 1.8 mmol / L;

[0057] 2. Add 3,4-ethylenedioxythiophene monomer to deionized water, stir to dissolve, and obtain EDOT solution; the concentration of 3,4-ethylenedioxythiophene monomer in the EDOT solution is 5 mmol / L;

[0058] 3. Add ammonium persulfate to deionized water and stir to dissolve to obtain an APS solution; the concentration of ammonium persulfate in the APS solution is 0.26 mol / L;

[0059] IV. Add 70 mL of EDOT solution to a 16 cm diameter petri dish, add 5 mL of 12 mol / L concentrated hydrochloric acid to the EDOT solution, and let it stand for 1 min at 25 °C. Then, add 141 μL of TPA solution to the surface of the solution at a dropping rate of 4 μL / s to 6 μL / s, and let it stand for 30 min at 25 °C. Finally, inject 1.47 mL of LAPS solution into the bottom of the solution at an injection rate of 0.1 mL / s to 0.2 mL / s, and heat and let it stand for 7 h at 60 °C to obtain a TPA / PEDOT composite film at the air-water interface.

[0060] The TPA / PEDOT composite film has a diameter of 16 cm and a thickness of 12 nm with uniform thickness.

[0061] Example 2: The aqueous zinc-ion battery is a Zn||Zn symmetric battery.

[0062] 1. Use sandpaper to polish the surface of the zinc sheet, then coat the polished zinc sheet with the TPA / PEDOT composite film prepared in Example 1 and dry it to obtain a zinc positive electrode and a zinc negative electrode with a protective layer.

[0063] 2. Assemble a button cell in the order of positive electrode, separator and negative electrode. The positive electrode is a zinc positive electrode with a protective layer, the negative electrode is a zinc negative electrode with a protective layer, the separator is a glass fiber membrane, and the electrolyte is a 2 mmol / L zinc sulfate aqueous solution to obtain an aqueous zinc ion Zn||Zn symmetric cell.

[0064] At a current density of 1 mA·cm -2 and a capacity of 1 mAh·cm -2Under the conditions described in Example 2, a constant current charge-discharge long-cycle test was conducted on the aqueous zinc-ion Zn||Zn symmetric battery. The test was conducted at a current density of 10 mA·cm⁻¹. -2 and a capacity of 10mAh·cm -2 Under the conditions specified, the aqueous zinc-ion Zn||Zn symmetric battery of Example 2 was subjected to constant current charge-discharge cycle test with a discharge depth of 62%.

[0065] Example 3: The aqueous zinc-ion battery is a Zn||Ti half-cell:

[0066] 1. The TPA / PEDOT composite film prepared in Example 1 is coated onto titanium foil and dried to obtain a titanium positive electrode with a protective layer; the surface of the zinc sheet is polished smooth with sandpaper, and then the TPA / PEDOT composite film prepared in Example 1 is coated onto the polished zinc sheet and dried to obtain a zinc negative electrode with a protective layer.

[0067] 2. Assemble a coin cell in the order of positive electrode, separator and negative electrode. The positive electrode is a titanium positive electrode with a protective layer, the negative electrode is a zinc negative electrode with a protective layer, the separator is a glass fiber membrane, and the electrolyte is a 2 mmol / L zinc sulfate aqueous solution to obtain an aqueous zinc ion Zn||Ti half cell.

[0068] At a current density of 2 mA·cm -2 and a capacity of 1 mAh·cm -2 Under the conditions specified, the aqueous zinc-ion Zn||Ti half-cell of Example 3 was subjected to constant current charge-discharge long cycle test.

[0069] Comparative Experiment 1: The difference between this embodiment and Embodiment 2 is that both the positive and negative electrodes are ordinary zinc sheets that have been polished. Everything else is the same as in Embodiment 2.

[0070] Comparative Experiment 2: The difference between this embodiment and Embodiment 3 is that the positive electrode is ordinary titanium foil; the negative electrode is ordinary zinc sheet after polishing. Everything else is the same as in Embodiment 3.

[0071] The transfer process of the TPA / PEDOT composite film prepared in Example 1: A petri dish (16 cm in diameter) containing the TPA / PEDOT composite film was placed in a plastic container (35 cm in diameter). Water was added to the petri dish along its edge until it was full. Then, water was added to the plastic container until the water level covered the petri dish. At this point, the TPA / PEDOT composite film floated out of the petri dish as the liquid level rose and floated at the air-water interface. A solid substrate (such as a zinc sheet) was placed under the film and then lifted upwards. The film was then transferred to the solid substrate. Figure 1The image shows the TPA / PEDOT composite film prepared in Example 1 floating on the air-water interface. a is a plastic container, b is a petri dish, the black substance in b is the precipitate generated during film preparation, and c is a TPA / PEDOT composite film with a diameter of 16 cm.

[0072] Figure 2 The image shows a scanning electron microscope image of the TPA / PEDOT composite film prepared in Example 1; as can be seen from the image, the film is uniform and continuous.

[0073] Figure 3 The image shows a transmission electron microscope image of the TPA / PEDOT composite film prepared in Example 1; as can be seen from the image, the film is uniform and dense.

[0074] Figure 4 The image shows an atomic force microscope image of the TPA / PEDOT composite film prepared in Example 1; as can be seen from the image, the thickness of the film is approximately 12 nm.

[0075] Figure 5 The figure shows the full spectrum of XPS test of the TPA / PEDOT composite film prepared in Example 1. As can be seen from the figure, the characteristic peaks of C1s, O1s, S2p orbitals are clearly present, proving the presence of the PEDOT part of the film.

[0076] Figure 6 The XPS test N1s fine spectrum of the TPA / PEDOT composite film prepared in Example 1 shows that the characteristic peak of the N1s orbital confirms the presence of the TPA film.

[0077] Figure 7 The figure shows a comparison of the contact angle test results of zinc sulfate electrolyte with a concentration of 2 mol / L. a) is the untreated zinc sheet, and b) is the zinc negative electrode with protective layer prepared in Example 2. As can be seen from the figure, the contact angle between the untreated zinc sheet and the 2 mol / L zinc sulfate aqueous solution is 75°, and the contact angle between the protective layer and the 2 mol / L zinc sulfate aqueous solution is 91°. This shows that the zinc sheet is hydrophobic and can isolate the direct contact between the electrolyte and the zinc negative electrode, thus inhibiting corrosion.

[0078] Figure 8 Example 2: Aqueous Zinc-Ion Zn||Zn Symmetric Cell at a Current Density of 1 mA / cm² 2 and a capacity of 1mAh / cm² 2 The graph shows the long-cycle performance under certain conditions. As can be seen from the graph, the Zn||Zn symmetric cell assembled with zinc sheets with protective layers has an ultra-long cycle life of 3200h, which proves that the protective layer has the effect of promoting uniform deposition of zinc ions. In addition, the low polarization voltage (24mV) proves that the protective layer promotes the rapid transport of zinc ions, thus making nucleation easier.

[0079] Figure 9 To compare the experimental setup, an aqueous zinc-ion Zn||Zn symmetric cell was used at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm² 2 The figure shows the long-cycle performance under the specified conditions. As can be seen from the figure, the Zn||Zn symmetric cell assembled without the zinc sheet with the protective layer has a cycle life of 380h. After that, due to the uneven deposition of zinc ions, dendrite growth occurs, which punctures the separator and causes a short circuit in the cell. In addition, the cell has a large polarization voltage (41mV), indicating that the zinc ion transport is slow and the cell reaction kinetics are slow.

[0080] Figure 10 Example 2: Aqueous Zinc-Ion Zn||Zn Symmetric Cell at a Current Density of 10 mA / cm² 2 and a capacity of 10mAh / cm² 2 The figure shows the cycle performance of the zinc anode with a utilization rate of 62% under the harsh conditions. As can be seen from the figure, the Zn||Zn symmetric battery assembled with zinc foil with protective layer can still operate stably for 280h under the harsh condition of peeling depth reaching 62%, which proves its application prospect of realizing high volumetric energy density aqueous zinc-ion batteries.

[0081] Figure 11 To compare the experimental setup, an aqueous zinc-ion Zn||Zn symmetric cell was used at a current density of 10 mA / cm². 2 and a capacity of 10mAh / cm² 2 The graph shows the cycle performance of the zinc anode with a utilization rate of 62% under the harsh conditions. As can be seen from the graph, the Zn||Zn symmetric cell assembled without a protective layer of zinc foil cannot operate normally under the harsh condition of a peeling depth of 62%.

[0082] Figure 12 Example 3: Aqueous Zinc-Ion Zn||Ti Half-Cell at a Current Density of 2 mA / cm² 2 and a capacity of 1mAh / cm² 2 The graph shows the long-cycle performance under the specified conditions. As can be seen from the graph, the Zn||Ti half-cell assembled with titanium foil and zinc foil with protective layer can run stably for 3000 cycles and has a coulombic efficiency of up to 99.78%. This indicates that the protective layer can not only make zinc uniformly deposited on titanium foil and prevent short circuit problems caused by excessive dendrite growth, but also suppress zinc loss caused by side reactions and other problems.

[0083] Figure 13 To compare the two aqueous zinc-ion Zn||Ti half-cells, the current density was 2 mA / cm². 2 and a capacity of 1mAh / cm² 2The graph shows the long-cycle performance under the specified conditions. As can be seen from the graph, the Zn||Ti half-cell assembled with titanium foil and zinc foil without protective layer can only cycle normally for 380 cycles. After that, short circuits occur due to dendrite problems, and the coulombic efficiency fluctuates greatly.

[0084] Figure 14 Example 2: Aqueous Zinc-Ion Zn||Zn Symmetric Cell at a Current Density of 1 mA / cm² 2 and a capacity of 1mAh / cm² 2 Under the specified conditions, the XRD pattern of the zinc anode after 50 cycles is shown in the figure. As can be seen from the figure, the diffraction peaks of Zn on the electrode of the Zn||Zn symmetric cell assembled with zinc foil with protective layer are present after cycling, and there are no diffraction peaks of other substances, which proves that the protective layer can effectively suppress the formation of by-products during cycling.

[0085] Figure 15 To compare the experimental setup, an aqueous zinc-ion Zn||Zn symmetric cell was used at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm² 2 Under the conditions of 50 cycles, the XRD test pattern of the zinc anode is shown. As can be seen from the figure, after cycling, the Zn||Zn symmetric cell assembled with zinc foil without a protective layer not only has the diffraction peak of Zn on the electrode, but also the diffraction peak of the byproduct hydroxylated zinc sulfate. This proves that without the protection of the protective layer, the electrode will generate a severe passivation layer during cycling, which will affect the transport of zinc ions.

[0086] Figure 16 Example 2: Aqueous Zinc-Ion Zn||Zn Symmetric Cell at a Current Density of 1 mA / cm² 2 and a capacity of 1mAh / cm² 2 The surface morphology of the zinc anode after 50 cycles under the specified conditions is shown in the figure. As can be seen from the figure, zinc ions are deposited more uniformly under the protection of the protective layer.

[0087] Figure 17 To compare the experimental setup, an aqueous zinc-ion Zn||Zn symmetric cell was used at a current density of 1 mA / cm². 2 and a capacity of 1mAh / cm² 2 The surface morphology of the zinc negative electrode after 50 cycles under the specified conditions is shown in the figure. As can be seen from the figure, the zinc ion deposition on the bare zinc electrode is uneven and the surface is rough.

[0088] Figure 18 Example 3: Aqueous Zinc-Ion Zn||Ti Half-Cell at a Current Density of 2 mA / cm² 2 and a capacity of 1mAh / cm² 2 The capacity-voltage curve under the given conditions; as shown in the figure, the overpotential for nucleation of the battery with the protective layer is 96mV.

[0089] Figure 19 To compare the aqueous zinc ion Zn||Ti half-cell in Experiment 2 at a current density of 2 mA / cm² 2 and a capacity of 1mAh / cm² 2 The capacity-voltage curves under the given conditions are shown in the figure. As can be seen from the figure, the nucleation overpotential of the battery without the protective layer is 136mV, which is much larger than that of the battery with the protective layer. The smaller nucleation overpotential means faster nucleation, indicating that the protective layer accelerates the transport kinetics of zinc ions due to cation-π interaction.

[0090] To verify the cation-π interaction, protonated TPA was prepared: 5 mg of commercial TPA powder was placed in a glass bottle, and 20 μL of 12 mol / L concentrated hydrochloric acid was added. The mixture was protonated for 1 h at room temperature and then air-dried in a ventilated area to obtain protonated TPA powder. A mixture of protonated TPA and ZnSO4 was prepared: The protonated TPA powder and commercial ZnSO4 powder were mixed at a molar ratio of 4:1 and ground for 20 min to obtain the mixture.

[0091] Figure 20 The image shows the fine spectrum of Zn 2p obtained by XPS testing. 1 is ZnSO4 powder, and 2 is a mixture of protonated TPA and ZnSO4. As can be seen from the figure, the shift of the Zn 2p orbital peak is caused by the cation-π interaction, which proves its weak interaction between zinc ions and the thin film.

[0092] Figure 21 Nuclear magnetic resonance 1 The H spectrum shows that 1 represents protonated TPA and 2 represents a mixture of protonated TPA and ZnSO4. As can be seen from the figure, the proton chemical shift on the benzene ring is caused by the cation-π interaction, which proves its weak interaction between zinc ions and the thin film.

Claims

1. A method for preparing a nanoscale TPA / PEDOT composite film with uniform thickness, characterized in that... It is done in the following steps:

1. Add 4-amino-p-terphenyl to chloroform solution, stir to dissolve, and obtain TPA solution; 2. Add 3,4-ethylenedioxythiophene monomer to deionized water, stir to dissolve, and obtain EDOT solution; 3. Add ammonium persulfate to deionized water, stir to dissolve, and obtain APS solution; 4. Add concentrated hydrochloric acid to the EDOT solution and let it stand. Then, add TPA solution to the surface of the solution and let it stand. Finally, inject APS solution into the bottom of the solution and heat and let it stand. A uniform nanoscale TPA / PEDOT composite film is obtained at the air-water interface. The molar ratio of 3,4-ethylenedioxythiophene monomer in the EDOT solution to 4-amino-p-terphenyl in the TPA solution is 1:(0.0005-0.001); the molar ratio of 3,4-ethylenedioxythiophene monomer in the EDOT solution to ammonium persulfate in the APS solution is 1:(1-3).

2. The method for preparing a uniformly thick nanoscale TPA / PEDOT composite film according to claim 1, characterized in that... The concentration of 4-amino-p-terphenyl in the TPA solution described in step one is 1 mmol / L to 3 mmol / L.

3. The method for preparing a uniformly thick nanoscale TPA / PEDOT composite film according to claim 1, characterized in that... The concentration of 3,4-ethylenedioxythiophene monomer in the EDOT solution described in step two is 3 mmol / L to 15 mmol / L.

4. The method for preparing a uniformly thick nanoscale TPA / PEDOT composite film according to claim 1, characterized in that... The concentration of ammonium persulfate in the APS solution mentioned in step three is 0.2 mol / L to 0.5 mol / L.

5. The method for preparing a uniformly thick nanoscale TPA / PEDOT composite film according to claim 1, characterized in that... The concentration of the concentrated hydrochloric acid mentioned in step four is 8 mol / L to 12 mol / L.

6. The method for preparing a uniformly thick nanoscale TPA / PEDOT composite film according to claim 3, characterized in that... The volume ratio of EDOT solution to concentrated hydrochloric acid in step four is (12-15):

1.

7. The method for preparing a uniformly thick nanoscale TPA / PEDOT composite film according to claim 1, characterized in that... In step four, concentrated hydrochloric acid is added to the EDOT solution, and the solution is allowed to stand at room temperature for 1 to 5 minutes.

8. The method for preparing a uniformly thick nanoscale TPA / PEDOT composite film according to claim 1, characterized in that... In step four, TPA solution is added to the surface of the solution at a dropping rate of 4 μL / s to 6 μL / s, and the solution is left to stand at room temperature for 30 min to 40 min.

9. The method for preparing a uniformly thick nanoscale TPA / PEDOT composite film according to claim 1, characterized in that... In step four, APS solution is injected into the bottom of the solution at an injection rate of 0.1 mL / s to 0.2 mL / s, and then heated and allowed to stand for 7 to 12 hours at a temperature of 30°C to 80°C.

10. The application of the uniformly thick nanoscale TPA / PEDOT composite film prepared according to claim 1, characterized in that... It is used as an interfacial protective layer for the zinc anode in aqueous zinc-ion batteries.

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