Proton library interface based on proton coupling electron transfer and application of proton library interface in aqueous zinc ion battery

Abstract

The invention discloses a proton library interface based on proton coupling electron transfer and application of the proton library interface in an aqueous zinc ion battery, and belongs to the field of metal zinc negative electrodes of the aqueous zinc ion battery. The invention aims to solve the problems of dendritic crystal growth, hydrogen evolution reaction and interface corrosion of a zinc metal negative electrode in an aqueous zinc ion battery in the prior art. And the proton library interface is formed by combining the polyoxometalates and a conductive polymer through electrostatic interaction, and the polyoxometalates are uniformly distributed in the conductive polymer. The application is as follows: in an aqueous zinc ion battery, the multi-metal oxygen cluster in a proton library interface provides a proton coupling electron transfer mechanism, and the conductive polymer provides uniform potential distribution, inhibits zinc dendritic crystal initiation, inhibits hydrogen evolution reaction and inhibits interface corrosion.

Description

Technical Field

[0001] The invention belongs to the field of metallic zinc negative electrodes of aqueous zinc ion batteries. Background Art

[0002] Aqueous zinc-ion batteries (AZIBs) have become a promising next-generation energy storage system due to the intrinsic safety, cost-effectiveness, and natural abundance of zinc resources offered by their aqueous electrolytes. However, the inherent uncontrollable dendrite growth, vigorous hydrogen evolution reaction (HER), and persistent interfacial corrosion of the zinc metal anode have severely hindered its large-scale commercialization. During the electrochemical deposition of zinc on the pristine metal surface, structural defects such as scratches, dents, and cracks can cause local electric field distortion and concentration polarization, thereby inducing uncontrollable dendrite growth. Dendrite accumulation not only increases surface activity and accelerates parasitic side reactions, but also leads to short circuits. Because the potential of zinc electroplating (-0.76 V vs. the standard hydrogen electrode potential) is lower than that of the standard hydrogen electrode, the HER and zinc deposition reactions are in constant competition. The HER rapidly raises the local pH, promoting the formation of byproducts such as Zn4SO4(OH)6·xH2O (at pH > 5), further destabilizing the electrode. This self-reinforcing vicious cycle ultimately leads to a significant decrease in the coulombic efficiency (CE) of the zinc anode, severely limiting the battery's cycle life.

[0003] Although significant progress has been made in zinc anode modification through artificial solid electrolyte interface (SEI) engineering strategies, existing single-component protective layers all have functional defects: for example, organic polymer layers can inhibit dendrite penetration, but it is difficult to precisely control ion flux; while inorganic interfacial phases can partially passivate the interface, their inhibitory effect on water-induced side reactions is limited. More importantly, existing strategies cannot simultaneously address the problems of dendrite growth, hydrogen evolution reaction, and interfacial corrosion at the zinc metal anode in aqueous zinc-ion batteries. Therefore, to overcome these persistent challenges, a new multidimensional interface engineering strategy that can synergistically integrate ion transport control, charge distribution regulation, and directional electrochemical reaction management is needed. Summary of the Invention

[0004] The present invention aims to solve the problems that existing strategies cannot simultaneously solve the dendrite growth, hydrogen evolution reaction and interface corrosion of the zinc metal negative electrode in aqueous zinc ion batteries, and further provides a proton reservoir interface based on proton-coupled electron transfer and its application in aqueous zinc ion batteries.

[0005] A proton reservoir interface based on proton-coupled electron transfer, which is formed by combining polyoxometallic clusters with conductive polymers through electrostatic interaction, and the polyoxometallic clusters are uniformly distributed in the conductive polymers;

[0006] The polymetallic oxygen cluster is PMo 11 V; the conductive polymer is poly (3,4-ethylenedioxythiophene).

[0007] The application of proton reservoir interface based on proton-coupled electron transfer in aqueous zinc-ion batteries. In aqueous zinc-ion batteries, the polymetallic oxygen clusters in the proton reservoir interface provide a proton-coupled electron transfer mechanism, and the conductive polymer provides a uniform potential distribution, which inhibits the initiation of zinc dendrites, inhibits hydrogen evolution reaction, and inhibits interface corrosion.

[0008] The beneficial effects of the present invention are:

[0009] In order to enhance electron transport and ensure uniform dispersion of POM clusters, the present invention 11 V was embedded in the conductive polymer PEDOT to construct an artificial solid electrolyte interface (SEI) on the surface of the zinc negative electrode, named PP / Zn. The comparative experiment used pure PEDOT (PA / Zn) without POM clusters as a control. The POM clusters with electron-coupled proton transfer mechanism constructed a proton buffer reservoir, which made the zinc negative electrode 2 The research team achieved 3,000 cycles (with an average coulombic efficiency of 99.77%) under low temperature and high pressure conditions, and the capacity retention rate of the soft-pack battery reached 87% after 100 cycles. At the same time, the interfacial hydrogen evolution reaction was inhibited, the amount of by-products generated was reduced, and the pH fluctuation of the electrolyte was stabilized through the in-situ proton regulation mechanism, which overcame the problem of coordinated regulation of zinc metal negative electrode dendrite growth, hydrogen evolution corrosion and ion transport hysteresis, and provided a solution with both theoretical innovation and process feasibility for the industrialization of high-safety and long-life aqueous zinc batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Schematic diagram of the proton fixation mechanism of the proton reservoir interface at the electrode-electrolyte interface based on proton-coupled electron transfer of the present invention;

[0011] Figure 2 For PMo in Example 1 11 Differential pulse voltammetry curves of V measured at different pH values, E pa is the anode peak potential, E pc is the cathode peak potential;

[0012] Figure 3 To utilize Figure 2 The fitted potential-pH relationship diagram, E pa is the anode peak potential, E pc is the cathode peak potential, E 1 / 2 is the half-wave potential;

[0013] Figure 4 Cyclic voltammetry curves of Zn||Ti battery in 2 mol / L zinc sulfate aqueous solution and PP nanofilm in 1 mol / L sulfuric acid aqueous solution;

[0014] Figure 5The linear sweep voltammetry (LSV) curves and corresponding hydrogen evolution potentials of the Zn||Cu half-cells assembled with different zinc negative electrodes in Example 1 and the comparative experiment are shown;

[0015] Figure 6 At 10mA / cm 2 In situ pH monitoring in a Zn||Zn symmetric cell during down-cycling;

[0016] Figure 7 This is the element distribution diagram of PP / Zn prepared in Example 1;

[0017] Figure 8 is the Tafel curve of Zn||Zn symmetric battery;

[0018] Figure 9 X-ray diffraction images of different electrode surfaces of the Zn||Zn symmetric battery after 20 cycles;

[0019] Figure 10 Kelvin probe force microscopy images of PP / Zn and bare zinc prepared in Example 1;

[0020] Figure 11 Actual photos and scanning electron microscope images of the PP nanofilm prepared in Example 1 and the PA nanofilm prepared in the comparative experiment, a is a photo of the PP nanofilm taken before transfer, b is a scanning electron microscope image of the PP nanofilm transferred to the silica substrate, c is a photo of the PA nanofilm taken before transfer, d is a scanning electron microscope image of the PA nanofilm transferred to the silica substrate;

[0021] Figure 12 Young's modulus images of the PP nanofilm prepared in Example 1 and the PA nanofilm prepared in the comparative experiment, a is the PP nanofilm, b is the PA nanofilm;

[0022] Figure 13 The UV-visible spectra of the PP nanofilm prepared in Example 1 and the PA nanofilm prepared in the comparative experiment, and the IV curves measured when loaded on interdigital electrodes, a is the UV-visible spectra, and b is the IV curve;

[0023] Figure 14 To perform linear voltammetric scans at a scan rate of 10 mV / s, the limiting current of the Zn||Zn symmetric cell was measured;

[0024] Figure 15 The double layer capacitance test of Ti||Ti symmetric battery and the calculation of zinc ion migration number of Zn||Zn symmetric battery are shown in Figure 1. a is the Ti||Ti symmetric battery and b is the Zn||Zn symmetric battery.

[0025] Figure 16Voltage-capacity curves of Zn||Zn symmetric batteries assembled with different electrodes;

[0026] Figure 17 At a current density of 2 mA / cm 2 The surface capacity is 1 mAh / cm 2 Under the conditions of constant current cycling performance of Zn||Zn symmetric battery;

[0027] Figure 18 At a current density of 5 mA / cm 2 The surface capacity is 1 mAh / cm 2 Under the conditions of constant current cycling performance of Zn||Zn symmetric battery;

[0028] Figure 19 At a current density of 10 mA / cm 2 The surface capacity is 1 mAh / cm 2 Under the conditions of constant current cycling performance of Zn||Zn symmetric battery;

[0029] Figure 20 It is the rate performance test of Zn||Zn symmetric battery;

[0030] Figure 21 At a current density of 1 mA / cm 2 The surface capacity is 10mAh / cm 2 Under the conditions of constant current cycling performance of Zn||Zn symmetric battery at high depth of discharge;

[0031] Figure 22 At a current density of 5 mA / cm 2 The surface capacity is 1 mAh / cm 2 Coulombic efficiency test of Zn||Cu half-cell under the conditions of;

[0032] Figure 23 The Zn||Cu half-cell assembled with bare copper and bare zinc was tested at 40 mA / cm 2 In situ optical microscopy image of the first plating / stripping cycle performed under ;

[0033] Figure 24 The Zn||Cu half-cell assembled with PA / Cu and PA / Zn was tested at 40 mA / cm 2 In situ optical microscopy image of the first plating / stripping cycle performed under ;

[0034] Figure 25 The Zn||Cu half-cell assembled with PP / Cu and PP / Zn was tested at 40 mA / cm 2 In situ optical microscopy image of the first plating / stripping cycle performed under ;

[0035] Figure 26 For Zn||Ti half-cell at 20 mA / cm 2 After electroplating for 1 h at a current density of , photographs were taken on both sides of the zinc layer obtained at the positive electrode;

[0036] Figure 27 For zinc-iodine full cell at 50 mA / cm 2 Long cycle performance at high current density;

[0037] Figure 28 For zinc-iodine full cell at 10 mA / cm 2 Cycling performance under

[0038] Figure 29 It is a negative electrode-free zinc-iodine full battery at 6.4mA / cm 2 Cycling performance under

[0039] Figure 30 The cycling performance of zinc-iodine soft-pack batteries. DETAILED DESCRIPTION

[0040] Specific embodiment 1: This embodiment is a proton reservoir interface based on proton-coupled electron transfer, which is formed by combining polymetallic oxide clusters and conductive polymers through electrostatic interaction, and the polymetallic oxide clusters are uniformly distributed in the conductive polymer;

[0041] The polymetallic oxygen cluster is PMo 11 V; the conductive polymer is poly (3,4-ethylenedioxythiophene).

[0042] Figure 1 Schematic diagram of the proton fixation mechanism of the proton reservoir interface at the electrode-electrolyte interface based on proton-coupled electron transfer in the present invention; As can be seen from the figure, the inherent proton fixation-release mechanism of polymetallic oxygen clusters can effectively remove excess free protons at the electrode-electrolyte interface, thereby reducing the local proton concentration and suppressing the driving force of HER by thermodynamics. 11 V can act as a dynamic proton reservoir, stabilizing the interfacial pH by competitively adsorbing protons, significantly alleviating side reactions such as dendrite growth, electrode corrosion, and HER, ultimately improving electrode stability.

[0043] In this embodiment, the proton-coupled electron transfer mechanism is provided by polyoxometalates, a unique property of these clusters. Because polyoxometalates are readily soluble in water and cannot be used directly as a coating for the zinc cathode, they are instead incorporated into a conductive polymer, an organic component. The electrostatic interaction between the two allows for a uniform distribution of the polyoxometalates throughout the conductive polymer.

[0044] The polyoxometallic cluster described in this embodiment is H4PMo 11 VO40 (PMo 11 V, namely POM), the anion part is [PMo 11 VO 40 ] 4- , the counter ion is H + .

[0045] The conductive polymer described in this embodiment is poly (3,4-ethylenedioxythiophene) (PEDOT), which is obtained by oxidative polymerization of 3,4-ethylenedioxythiophene monomer. The oxidant is directly selected from PMo 11 V.

[0046] In this embodiment, PEDOT acts as an electron averaging layer to eliminate local electric field distortion and inhibit the initiation of zinc dendrites; the highly electronegative POM clusters provide uniform nucleation sites to guide Zn 2+ At the same time, POM dynamically captures interfacial protons through the proton-coupled electron transfer mechanism to form stable intermediates, reducing the local proton concentration and thermodynamically inhibiting the hydrogen evolution reaction (HER), synergistically stabilizing the pH value of the electrolyte and accelerating the Zn 2+ Migration dynamics. This design provides a breakthrough solution for high-stability zinc-based energy storage systems and the rational design of metal electrode interfaces.

[0047] This specific embodiment is based on the innovative strategy of triple synergistic regulation of "electric field-ion-proton". By integrating the conductive polymer poly(3,4-ethylenedioxythiophene) and proton-coupled electron transfer (PCET) active polyoxometalates (POM) at the molecular level, a multifunctional composite interface PP / Zn is constructed, which effectively solves the problems of dendrite growth, hydrogen evolution reaction and interface corrosion of the zinc metal negative electrode.

[0048] The beneficial effects of this embodiment are:

[0049] In this embodiment, PMo is used to enhance electron transport and ensure uniform dispersion of POM clusters. 11 V was embedded in the conductive polymer PEDOT to construct an artificial solid electrolyte interface (SEI) on the surface of the zinc negative electrode, named PP / Zn. The comparative experiment used pure PEDOT (PA / Zn) without POM clusters as a control. The POM clusters with electron-coupled proton transfer mechanism constructed a proton buffer reservoir, which made the zinc negative electrode 2 The research team achieved 3,000 cycles (with an average coulombic efficiency of 99.77%) under low temperature and high pressure conditions, and the capacity retention rate of the soft-pack battery reached 87% after 100 cycles. At the same time, the interfacial hydrogen evolution reaction was inhibited, the amount of by-products generated was reduced, and the pH fluctuation of the electrolyte was stabilized through the in-situ proton regulation mechanism, which overcame the problem of coordinated regulation of zinc metal negative electrode dendrite growth, hydrogen evolution corrosion and ion transport hysteresis, and provided a solution with both theoretical innovation and process feasibility for the industrialization of high-safety and long-life aqueous zinc batteries.

[0050] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the construction method of the proton reservoir interface based on proton-coupled electron transfer is carried out according to the following steps:

[0051] PMo 11 The aqueous solution of V and 3,4-ethylenedioxythiophene was mixed to obtain a mixed solution, a surfactant solution was added dropwise to the surface of the mixed solution and allowed to stand, and PEDOT and PMo were obtained at the air-water interface. 11 V composite multifunctional organic-inorganic materials, PEDOT and PMo 11 The multifunctional organic-inorganic material V was transferred to the zinc substrate, and after drying, PEDOT / PMo was obtained on the zinc substrate. 11 The V modified layer completes the proton reservoir interface construction method based on proton coupled electron transfer. Other aspects are the same as those of the first embodiment.

[0052] Specific embodiment 3: This embodiment differs from specific embodiment 1 or 2 in that the surfactant solution is a chloroform solution of 2,2'-diamino-1,1'-binaphthyl with a concentration of 1.8 mmol / L to 2 mmol / L. Other aspects are the same as specific embodiment 1 or 2.

[0053] Specific embodiment 4: This embodiment is different from the specific embodiments 1 to 3 in that: the PMo in the mixed solution 11 The molar ratio of V to 3,4-ethylenedioxythiophene is 3:(15-20). Other aspects are the same as those of the first to third embodiments.

[0054] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that: PMo in the mixed solution 11 The molar ratio of V to the volume of water is 1 mmol: (1.3-1.4) L. Other aspects are the same as those of the first to fourth embodiments.

[0055] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that: the PMo 11 The molar ratio of V to the surfactant in the surfactant solution is (208-209): 1. Other aspects are the same as those in the first to fifth embodiments.

[0056] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the surfactant solution is added dropwise onto the surface of the mixed solution at a dropping speed of 5 μL / s to 10 μL / s. Other aspects are the same as specific embodiments 1 to 6.

[0057] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that: the mixture is left to stand at room temperature for 10 to 20 hours.

[0058] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the zinc substrate is the negative electrode of an aqueous zinc ion battery. Other aspects are the same as specific embodiments 1 to 8.

[0059] Specific embodiment ten: This embodiment is based on the application of the proton reservoir interface of proton-coupled electron transfer in aqueous zinc-ion batteries. In aqueous zinc-ion batteries, the polymetallic oxygen clusters in the proton reservoir interface provide a proton-coupled electron transfer mechanism, and the conductive polymer provides a uniform potential distribution, which inhibits the initiation of zinc dendrites, inhibits hydrogen evolution reaction, and inhibits interface corrosion.

[0060] The following examples are used to verify the beneficial effects of the present invention:

[0061] Example 1:

[0062] A proton reservoir interface based on proton-coupled electron transfer, which is formed by combining polyoxometallic clusters with conductive polymers through electrostatic interaction, and the polyoxometallic clusters are uniformly distributed in the conductive polymers;

[0063] The polymetallic oxygen cluster is PMo 11 V(POM); the conductive polymer is poly(3,4-ethylenedioxythiophene).

[0064] The above-mentioned method for constructing the proton reservoir interface based on proton-coupled electron transfer is carried out according to the following steps:

[0065] PMo 11 The aqueous solution of V and 3,4-ethylenedioxythiophene was mixed to obtain a mixed solution. The surfactant solution was added dropwise on the surface of the mixed solution at a dropping speed of 10 μL / s. The mixed solution was allowed to stand at room temperature for 15 h. After standing, PEDOT and PMo were obtained at the air-water interface. 11 V composite multifunctional organic-inorganic materials, PEDOT and PMo 11 The multifunctional organic-inorganic material of V composite is transferred to a zinc substrate, a copper substrate or a titanium substrate, and after drying, PEDOT / PMo is obtained on the zinc substrate, the copper substrate or the titanium substrate. 11 V modified layer (PP nanofilm), namely zinc electrode (PP / Zn), copper electrode (PP / Cu) or titanium electrode (PP / Ti) at the proton reservoir interface with proton-coupled electron transfer characteristics.

[0066] The surfactant solution is a chloroform solution of 2,2'-diamino-1,1'-binaphthyl with a concentration of 1.8 mmol / L.

[0067] PMo in the mixed solution 11 The molar ratio of V to 3,4-ethylenedioxythiophene is 3:20.

[0068] PMo in the mixed solution 11 The molar ratio of V to the volume of water is 1mmol:1.33L.

[0069] The PMo 11 The molar ratio of V to the surfactant in the surfactant solution was 208:1.

[0070] The PMo described in this embodiment 11 V was prepared according to the following reference: Wei, P.; Yang, Y.; Li, W.; Li, G., Keggin-POM@rht-MOF-1 composite as heterogeneous catalysts towards ultra-deep oxidative fuel desulfurization. Fuel 2020, 274, 117834.

[0071] Comparative experiment: Preparation of pure conductive polymer material without proton-coupled electron transfer properties is carried out according to the following steps:

[0072] An aqueous solution of ammonium persulfate and 3,4-ethylenedioxythiophene is mixed to obtain a mixed solution. A surfactant solution is added dropwise to the surface of the mixed solution at a dropping speed of 10 μL / s. The solution is allowed to stand at room temperature for 15 hours. After standing, poly(3,4-ethylenedioxythiophene) is obtained at the air-water interface. The poly(3,4-ethylenedioxythiophene) is transferred to a zinc substrate, a copper substrate or a titanium substrate. After drying, a PEDOT modified layer (PA nanofilm) is obtained on the zinc substrate, the copper substrate or the titanium substrate, i.e., a zinc electrode (PA / Zn), a copper electrode (PA / Cu) or a titanium electrode (PA / Ti) with a pure conductive polymer modified layer.

[0073] The surfactant solution is a chloroform solution of 2,2'-diamino-1,1'-binaphthyl with a concentration of 1.8 mmol / L.

[0074] The molar ratio of ammonium persulfate to 3,4-ethylenedioxythiophene in the mixed solution is 12:1.

[0075] The volume ratio of ammonium persulfate to water in the mixed solution is 6 mmol:1 L.

[0076] The molar ratio of the ammonium persulfate to the surfactant in the surfactant solution is 1667:1.

[0077] (1) Assembling Zn||Zn symmetrical cells and Ti||Ti symmetrical cells:

[0078] The Zn||Zn symmetrical battery is a CR2032 button cell assembled in the order of positive electrode, separator, and negative electrode. The positive electrode is PP / Zn, PA / Zn, or bare zinc, the negative electrode is PP / Zn, PA / Zn, or bare zinc, the separator is a glass fiber membrane, the electrolyte is a 2 mol / L zinc sulfate aqueous solution, the electrode is a disc with a diameter of 1 cm, and the volume of the electrolyte is 80 μL.

[0079] Ti||Ti symmetric cells were assembled according to the above method, with only the positive and negative electrodes replaced with PP / Ti, PA / Ti or bare titanium.

[0080] (2) Assembling Zn||Cu half-cell:

[0081] The Zn||Cu half-cell is assembled in the order of positive electrode, separator, and negative electrode. The positive electrode is PP / Cu, PA / Cu, or bare copper; the negative electrode is PP / Zn, PA / Zn, or bare zinc; the separator is a glass fiber membrane; the electrolyte is a 2 mol / L zinc sulfate aqueous solution; the electrode is a disc with a diameter of 1 cm; and the volume of the electrolyte is 80 μL.

[0082] Zn||Ti half-cells were assembled as described above, with the positive electrode replaced by PP / Ti, PA / Ti, or bare titanium (1 cm × 1 cm), and the negative electrode replaced by 1 cm × 1 cm PP / Zn, PA / Zn, or bare zinc.

[0083] (3) Assembling the zinc-iodine full battery:

[0084] 1. The negative electrode of the full battery uses PP / Zn or bare zinc (pressed into a disc with a diameter of 1 cm), and the positive electrode is an iodine electrode (a disc with a diameter of 1 cm);

[0085] 2. Preparation of iodine electrode: First, 0.5 g of activated carbon, SuperP conductive agent and polytetrafluoroethylene (PTFE) (mass ratio of 8:1:1) were added to 30 mL of ethanol solution to mix to obtain a slurry. Then, the slurry was applied to the surface of the titanium mesh current collector (area size of 5 cm × 5 cm) at a coating amount of 0.7 g, and dried at a temperature of 60 ° C for 12 hours to obtain a self-supporting current collector; the obtained self-supporting current collector was pressed into a disc with a diameter of 1 cm using a tablet press; after dissolving 1 g of iodine in 10 mL of ethanol, if 53 μL of the drop coating amount was applied to the above disc, the surface loading of the active substance iodine was 6.8 mg / cm 2 If 196 μL of drop coating is applied to the above disc, the surface loading of active substance iodine is 25 mg / cm 2, dried at room temperature for 24 hours to obtain an iodine electrode;

[0086] 3. The full battery uses 2 mol / L zinc sulfate electrolyte with an electrolyte volume of 80 μL. The diaphragm is a glass fiber membrane. The CR2032 button cell is assembled in the order of positive electrode, diaphragm and negative electrode.

[0087] (4) Assembling a negative electrode-free zinc-iodine full battery:

[0088] 1. The iodine electrode was prepared by the method (3), except that the amount of the drop coating was 71 μL and the surface loading of the active material iodine was 9.09 mg / cm 2 The negative electrode used PP / Zn or bare zinc (pressed into a disc with a diameter of 1 cm), the electrolyte was 2 mol / L zinc sulfate electrolyte, the electrolyte volume was 80 μL, and the separator was a glass fiber membrane. CR2032 button cells were assembled in the order of positive electrode, separator, and negative electrode. The assembled zinc-iodine full battery was discharged to 0.3 V.

[0089] 2. Disassemble the battery, soak the positive electrode (iodine electrode) in ultrapure water, and then dry it as the positive electrode of the battery without negative electrode;

[0090] 3. The negative electrode was replaced with PP / Cu or bare Cu (evenly pressed into a disc with a diameter of 1 cm). The electrolyte was a mixture of zinc sulfate and zinc trifluoromethanesulfonate in a molar ratio of 3:1 (total concentration 1.5 mol / L), and then zinc chloride was added to make the total zinc ion concentration reach 2 mol / L; the electrolyte volume was 80 μL, and the separator was a glass fiber membrane. CR2032 button batteries were assembled in the order of positive electrode, separator and negative electrode to obtain a zinc-iodine full battery without a negative electrode (the negative electrode was copper instead of zinc).

[0091] (5) Assembling zinc-iodine soft pack batteries:

[0092] 1. Prepare three 6 cm × 6 cm self-supporting current collectors using method (3);

[0093] 2. 60 mL of iodine solution (6 g of iodine dissolved in 60 mL of ethanol) was drop-coated on the surface of the self-supporting current collector in batches and dried at room temperature for 48 hours to obtain a positive electrode sheet (iodine positive electrode);

[0094] 3. The positive electrode sheet needs to be soaked in 2 mol / L zinc sulfate electrolyte for 24 hours before battery assembly. The amount of electrolyte used is 30 mL.

[0095] 4. The negative electrode uses four 6cm×6cm PP / Zn pieces;

[0096] 5. The electrolyte used is 2mol / L zinc sulfate electrolyte, the electrolyte dosage is 30mL, and the diaphragm is a glass fiber membrane. The soft-pack battery is assembled in the order of negative electrode, diaphragm, positive electrode, diaphragm, negative electrode, diaphragm, positive electrode, diaphragm, negative electrode, diaphragm, positive electrode, diaphragm, and negative electrode.

[0097] PMo 11 V was loaded onto a glassy carbon electrode as the working electrode, a platinum wire electrode was selected as the counter electrode, and a silver / silver chloride electrode was selected as the reference electrode. PMo was tested in a 1 mol / L sulfuric acid electrolyte. 11 Differential pulse voltammetry curves of V at different pH; Figure 2 For PMo in Example 1 11 Differential pulse voltammetry curves of V measured at different pH values, E pa is the anode peak potential, E pc is the cathode peak potential; as shown in the figure, with the increase of electrolyte pH, the anode peak potential and the cathode peak potential shift to a lower potential.

[0098] Figure 3 To utilize Figure 2 The fitted potential-pH relationship diagram, E pa is the anode peak potential, E pc is the cathode peak potential, E 1 / 2 is the half-wave potential; the half-wave potential is the thermodynamic equilibrium potential, and E pa and E pc The figure shows that the anodic peak potential, cathodic peak potential and half-wave potential are linearly related to the pH of the electrolyte, and the slope is close to the theoretical value of 59mV / pH, confirming the proton-coupled electron transfer mechanism. The transfer of one electron is accompanied by the transfer of one proton. The Nernst equation is as follows:

[0099]

[0100] In the equation, n is the number of electrons transferred, m is the number of protons transferred, and E 0 is the standard electrode potential, and E is the actual electrode potential.

[0101] A three-electrode system was used, with a 1 cm × 1 cm titanium foil as the working electrode, a 1 cm × 1 cm zinc foil as the counter electrode, a silver / silver chloride electrode as the reference electrode, and a 2 mol / L zinc sulfate aqueous solution as the electrolyte. Cyclic voltammetry curves of the Zn||Ti battery were tested at a scan rate of 10 mV / s. A glassy carbon electrode loaded with a PP nanofilm was used as the working electrode, a platinum wire electrode as the counter electrode, and a silver / silver chloride electrode as the reference electrode. The electrolyte was a 1 mol / L sulfuric acid aqueous solution, and cyclic voltammetry curves of the PP nanofilm were tested at a scan rate of 10 mV / s. Figure 4The cyclic voltammetry curves of Zn||Ti battery in 2 mol / L zinc sulfate aqueous solution and PP nanofilm in 1 mol / L sulfuric acid aqueous solution are shown in the figure. As can be seen from the figure, there are three obvious redox processes in the PP nanofilm (attributed to PMo 11 V, corresponding to the redox reaction of polyoxometalates), and its potential window is significantly earlier than the zinc deposition potential.

[0102] Figure 5 The linear sweep voltammetry (LSV) curves and corresponding hydrogen evolution potentials of the Zn||Cu half-cells assembled with different zinc negative electrodes in Example 1 and the comparative experiment; the electrolyte was replaced with a 1 mol / L sodium sulfate aqueous solution to eliminate the influence of zinc ions in the electrolyte; as can be seen from the figure, the HER onset potential of the PP / Zn battery shifted significantly negatively, which inhibited the occurrence of HER to a certain extent.

[0103] The positive and negative electrodes of the Zn||Zn symmetric battery are 1 cm × 1 cm in size and are 2 The battery was continuously charged and discharged at a current density of 100 nm to perform in situ pH monitoring. Figure 6 At 10mA / cm 2 In situ pH monitoring in the Zn||Zn symmetric cell during the down cycle; as can be seen from the figure, the pH of the bare zinc electrode rises sharply (continuously rising from 4 to 4.8), indicating intense HER activity, while the pH of the PP / Zn electrode is stable (basically stable around 4.2), providing in situ evidence for the proton buffering effect of the PP nanomembrane.

[0104] Figure 7 This is the element distribution diagram of PP / Zn prepared in Example 1; it can be seen from the figure that PMo 11 V is evenly distributed in the PEDOT matrix, confirming its successful immobilization and uniform dispersion.

[0105] Figure 8 The Tafel curve of the Zn||Zn symmetric battery is shown in the figure. As shown in the figure, the symmetric battery assembled with zinc electrodes modified by PP nanofilm exhibits a higher corrosion potential, which is 18mV higher than that of the bare zinc symmetric battery, indicating that PP / Zn has stronger chemical corrosion resistance and inhibits the corrosion of the electrode interface to a certain extent.

[0106] The Zn||Zn symmetric battery assembled with different electrodes was tested at 10 mA / cm 2 and 1mAh / cm 2 The battery was cycled 20 times, and then the battery was disassembled, the electrode sheets were taken out, rinsed with water and dried for X-ray diffraction measurement; Figure 9Figure 2 is the X-ray diffraction image of different electrode surfaces after the Zn||Zn symmetric battery was cycled 20 times; as shown in the figure, there is no characteristic peak of by-products (hydroxylated zinc sulfate) on the surface of the PP / Zn electrode, only the characteristic peak of zinc metal. In contrast, the surface of the bare zinc electrode has obvious characteristic peaks of by-products (before 10° and 20°), indicating that the PP nanofilm inhibits the formation of interfacial by-products.

[0107] Figure 10 Kelvin probe force microscopy images of PP / Zn and bare zinc prepared in Example 1; as can be seen from the figure, PP / Zn exhibits a significantly reduced and highly uniform surface potential distribution. The lower surface potential indicates that the PP coating enhances the interfacial electronegativity and promotes the rapid and uniform deposition of zinc ions through electrostatic interaction with positively charged zinc ions. The highly uniform surface potential distribution is conducive to the homogenization of zinc ion distribution and promotes uniform zinc ion deposition.

[0108] Figure 11 The following are photos and scanning electron microscope images of the PP nanofilm prepared in Example 1 and the PA nanofilm prepared in the comparative experiment. a is a photo of the PP nanofilm before transfer, b is a scanning electron microscope image of the PP nanofilm transferred to the silica substrate, c is a photo of the PA nanofilm before transfer, and d is a scanning electron microscope image of the PA nanofilm transferred to the silica substrate. As can be seen from Figure a, the PP nanofilm exhibits a highly continuous and uniform morphology before transfer. As can be seen from Figure b, the nanofilm still maintains its intact structure after transfer to the substrate. Its stability mainly comes from the PMo 11 V and PEDOT form an organic-inorganic composite structure. As shown in Figure c, the PA nanofilm is broken before transfer. As shown in Figure d, there is obvious structural cracking after transfer, highlighting the PMo 11 The role of V.

[0109] Figure 12 Figures (a) and (b) show the Young's modulus of the PP nanofilm prepared in Example 1 and the PA nanofilm prepared in a comparative experiment. The PP nanofilm has a Young's modulus of 18 GPa, while the PA nanofilm has a Young's modulus of approximately 4 GPa, demonstrating the PP nanofilm's good mechanical stability.

[0110] The PP nanofilm prepared in Example 1 and the PA nanofilm prepared in the comparative experiment were loaded onto interdigitated electrodes (10 pairs of 20 fingers, with a finger spacing of 100 μm, a finger width of 100 μm, and a finger length of 4 mm). After drying, IV curves were measured using a 2450 source meter. Figure 13 The UV-visible spectra of the PP nanofilm prepared in Example 1 and the PA nanofilm prepared in the comparative experiment and the IV curves measured when loaded on the interdigital electrodes, a is the UV-visible spectra, b is the IV curve; As can be seen from Figure a, the π-π* The electron transition absorption is significantly enhanced, indicating that PEDOT and PMo 11 The strong interaction of V extends the conjugated chain and improves the order of the polymer. As shown in Figure b, the conductivity of the PP nanofilm / interdigital electrode is 9 orders of magnitude higher than that of the PA nanofilm / interdigital electrode. This improvement in conductivity directly promotes electron transfer at the electrode-electrolyte interface and strengthens the PMo 11 Proton-coupled electron transfer effect of V.

[0111] Figure 14 A linear voltammetric scan was performed at a scan rate of 10 mV / s to measure the limiting current of the Zn||Zn symmetric cell. As can be seen from the figure, the diffusion-controlled limiting current of the PP / Zn electrode was delayed (-0.39 V) compared with the bare zinc electrode (-0.34 V), indicating improved stability against concentration polarization. In addition, the PP / Zn electrode had a higher limiting current (217 mA) than the bare zinc electrode (183 mV), which directly demonstrated the accelerated zinc ion charge transfer kinetics and highlighted the enhanced transport capacity imparted by the PP nanofilm.

[0112] Figure 15 The double-layer capacitance test of Ti||Ti symmetric battery and the calculation of zinc ion migration number of Zn||Zn symmetric battery are shown in Figure 1. a is Ti||Ti symmetric battery and b is Zn||Zn symmetric battery. The double-layer capacitance of Ti||Ti symmetric battery was evaluated by cyclic voltammetry test. As shown in Figure 1, it is obvious that PP / Ti battery has the highest double-layer capacitance (182μF / cm 2 ), compared with PA / Ti battery (68μF / cm 2 ) and bare titanium battery (54μF / cm 2 ) are much higher. This significant increase in interfacial capacitance indicates enhanced zinc ion accumulation in the double layer, a key prerequisite for uniform zinc nucleation. As shown in Figure b, the PP / Zn symmetric cell has a high zinc ion transference number of 0.75, while the bare zinc symmetric cell has a zinc ion transference number of only 0.34. The PA / Zn symmetric cell has a zinc ion transference number of 0.49, indicating that the PP nanofilm accelerates zinc ion migration within the cell and exhibits rapid reaction kinetics.

[0113] In method (1), a Zn||Zn symmetrical battery was assembled using a zinc foil with a thickness of 30 μm. 2 Discharge continues at a current density of Figure 16 The voltage-capacity curves of Zn||Zn symmetric batteries assembled with different electrodes. As shown in the figure, the surface capacity of the completely stripped PP / Zn electrode is 14.4 mAh / cm 2 , close to the theoretical value of 15.7mAh / cm 2, while the surface capacity of bare zinc electrode is 1.4 mAh / cm 2 This indicates that the PP / Zn electrode can provide a uniform zinc ion flux, which promotes uniform zinc stripping, while the zinc ion flux of the bare zinc electrode is extremely uneven, and local rapid and complete stripping is achieved.

[0114] Figure 17 At a current density of 2 mA / cm 2 The surface capacity is 1 mAh / cm 2 Figure 3 shows the constant current cycling performance of Zn||Zn symmetric batteries under the conditions of 1.5 GHz and 1.5 GHz; as shown in the figure, the PP / Zn symmetric battery maintains a stable and low polarization voltage within 1300 h, while the PA / Zn and bare zinc symmetric batteries will experience dendrite-induced short circuits after 310 h and 180 h respectively.

[0115] Figure 18 At a current density of 5 mA / cm 2 The surface capacity is 1 mAh / cm 2 Under the conditions of constant current cycling performance of Zn||Zn symmetric battery; as shown in the figure, the PP / Zn symmetric battery can operate stably for 1400 hours.

[0116] Figure 19 At a current density of 10 mA / cm 2 The surface capacity is 1 mAh / cm 2 The constant current cycling performance of the Zn||Zn symmetric battery under the conditions of PP / Zn is shown in the figure. As shown in the figure, the PP / Zn symmetric battery can also significantly improve the cycle life at a low and stable polarization voltage (54mV vs. 85mV of bare zinc).

[0117] Figure 20 This is the rate performance test of Zn||Zn symmetric battery. As can be seen from the figure, the PP / Zn symmetric battery has a high rate performance when the current density is from 1mA / cm 2 Up to 50mA / cm 2 The overpotential is always kept low within the range of 50mA / cm 2 The polarization of the PP / Zn battery is only 120 mV, which is much lower than that of the bare Zn battery (230 mV) and the PA / Zn battery (170 mV).

[0118] Figure 21 At a current density of 1 mA / cm 2 The surface capacity is 10mAh / cm 2 Under the conditions of 1.5% and 2.5% depth of discharge, the constant current cycling performance of the Zn||Zn symmetrical battery at high depth of discharge is shown in the figure. As can be seen from the figure, at a depth of discharge of 64%, the cycle life of the PP / Zn symmetrical battery exceeds 300 hours, which is 3.5 times and 6.4 times that of PA / Zn and bare zinc respectively.

[0119] Figure 22 At a current density of 5 mA / cm 2 The surface capacity is 1 mAh / cm 2 Coulombic efficiency test of Zn||Cu half-cell under conditions of ; As can be seen from the figure, the Coulombic efficiency of the bare electrode fluctuates significantly, and after 500 cycles, it eventually fails due to a large amount of dendrite growth and side reactions; similarly, the half-cell assembled after PA protection fails after 650 cycles; It is worth noting that the half-cell after PP protection shows excellent stability, maintaining a high average Coulombic efficiency of 99.77% for more than 3000 cycles, highlighting the effectiveness of PP nanofilm in uniform zinc plating / stripping.

[0120] Figure 23 The Zn||Cu half-cell assembled with bare copper and bare zinc was tested at 40 mA / cm 2 In situ optical microscope image of the first electroplating / stripping cycle performed under the following conditions; charging (electroplating) was performed for 10 minutes, followed by discharging (stripping) for 10 minutes, with microscope images taken every 5 minutes. As can be seen from the image, severe dendrite accumulation and irregular protrusions quickly form on the surface of the bare Cu electrode, indicating uncontrolled deposition and violent side reactions; a large amount of zinc debris remains after stripping.

[0121] Figure 24 The Zn||Cu half-cell assembled with PA / Cu and PA / Zn was tested at 40 mA / cm 2 In situ optical microscope image of the first electroplating / stripping cycle performed under the following conditions; charging (electroplating) was performed for 10 minutes, followed by discharging (stripping) for 10 minutes, with microscope images taken every 5 minutes. As can be seen from the figure, although the PA / Cu electrode has reduced dendrites, uneven deposition still exists; zinc debris still remains after stripping.

[0122] Figure 25 The Zn||Cu half-cell assembled with PP / Cu and PP / Zn was tested at 40 mA / cm 2 In situ optical microscope image of the first electroplating / stripping cycle performed under the conditions of 10 min of charging (electroplating) and 10 min of discharging (stripping), with microscope images taken every 5 min. As can be seen from the figure, the PP / Cu electrode exhibits a uniform and dense zinc deposition morphology, and there are no visible dendrites or abnormal structures during the entire electroplating process, confirming that the PP nanofilm can effectively regulate the zinc ion flux and suppress local deposition hotspots. The zinc layer is evenly removed during the stripping process.

[0123] Zn||Ti half-cell at 20 mA / cm 2 When discharged for 1 h at a current density of , 20 mAh / cm2 can be deposited on the positive electrode. 2 Zinc: peel the deposited zinc off the positive electrode and photograph its front and back sides; Figure 26For Zn||Ti half-cell at 20 mA / cm 2 After electroplating for 1 hour at a current density of 100 nm, photos were taken on the front and back of the zinc layer obtained at the positive electrode. As shown in the figure, the zinc layer peeled off from the PP / Ti substrate is dense and uniform, in sharp contrast to the rough layer peeled off from the bare Ti electrode.

[0124] Figure 27 For zinc-iodine full cell at 50 mA / cm 2 The long cycle performance at high current density is shown in the figure. As can be seen from the figure, the bare zinc battery fails after 3000 cycles due to short circuit caused by dendrites, while the PP / Zn battery can stably cycle 20000 times without capacity decay.

[0125] Figure 28 For zinc-iodine full cell at 10 mA / cm 2 The cycling performance under the condition of PP / Zn battery is 5.7 mAh / cm 2 The surface capacity of the battery can be stably cycled for 300 times, while the capacity of the bare zinc battery decays sharply after 90 cycles due to zinc depletion, highlighting the advantages of PP nanofilm in uniform zinc deposition and active material retention.

[0126] Figure 29 It is a negative electrode-free zinc-iodine full battery at 6.4mA / cm 2 Cycling performance under the conditions of 100 cycles; As can be seen from the figure, the negative electrode-free zinc-iodine full battery constructed with PP nanofilm achieves an energy density of 253Wh / kg (based on the mass of the positive and negative electrodes), stable cycling for 650 times, and a capacity retention rate of 72%, far exceeding that of bare zinc batteries (failure within 100 cycles). The energy density calculation process is as follows:

[0127]

[0128] Where M is the surface loading of the active substance iodine, which is 9.09 mg / cm 2 , S is the effective area, which is 0.785cm 2 , E is the energy of the first discharge, which is 1.82mWh.

[0129] Figure 30 The cycling performance of zinc-iodine soft pack battery is shown in the figure. As shown in the figure, the PP / Zn assembled ampere-hour soft pack battery (with the first discharge capacity of 1.34Ah) is 5.5mA / cm 2 The capacity retention rate reached 87% after 100 cycles, proving the feasibility of large-scale application of PP nanomembrane.

Claims

1. A proton reservoir interface based on proton-coupled electron transfer, characterized in that It is formed by combining polymetallic oxide clusters with conductive polymers through electrostatic interaction, and the polymetallic oxide clusters are evenly distributed in the conductive polymers; The polymetallic oxygen cluster is PMo 11 V; the conductive polymer is poly (3,4-ethylenedioxythiophene).

2. A proton reservoir interface based on proton coupled electron transfer according to claim 1, characterized in that Its construction method is carried out according to the following steps: PMo 11 The aqueous solution of V and 3,4-ethylenedioxythiophene was mixed to obtain a mixed solution, a surfactant solution was added dropwise to the surface of the mixed solution and allowed to stand, and PEDOT and PMo were obtained at the air-water interface. 11 V composite multifunctional organic-inorganic materials, PEDOT and PMo 11 The multifunctional organic-inorganic material V was transferred to the zinc substrate, and after drying, PEDOT / PMo was obtained on the zinc substrate. 11 The V modified layer completes the proton reservoir interface construction method based on proton-coupled electron transfer.

3. A proton reservoir interface based on proton coupled electron transfer according to claim 2, characterized in that The surfactant solution is a chloroform solution of 2,2'-diamino-1,1'-binaphthyl with a concentration of 1.8 mmol / L to 2 mmol / L.

4. A proton reservoir interface based on proton coupled electron transfer according to claim 2, characterized in that PMo in the mixed solution 11 The molar ratio of V to 3,4-ethylenedioxythiophene is 3:(15-20).

5. A proton reservoir interface based on proton coupled electron transfer according to claim 2, characterized in that PMo in the mixed solution 11 The molar ratio of V to the volume of water is 1mmol:(1.3~1.4)L.

6. A proton reservoir interface based on proton coupled electron transfer according to claim 2, characterized in that The PMo 11 The molar ratio of V to the surfactant in the surfactant solution is (208-209):

1.

7. A proton reservoir interface based on proton coupled electron transfer according to claim 2, characterized in that The surfactant solution is added dropwise onto the surface of the mixed solution at a dropping speed of 5 μL / s to 10 μL / s.

8. A proton reservoir interface based on proton coupled electron transfer according to claim 2, characterized in that Let stand at room temperature for 10 to 20 hours.

9. A proton reservoir interface based on proton coupled electron transfer according to claim 2, characterized in that The zinc substrate is the negative electrode of the aqueous zinc ion battery.

10. The use of the proton reservoir interface based on proton coupled electron transfer in aqueous zinc ion batteries according to claim 1, characterized in that In aqueous zinc-ion batteries, polymetallic oxygen clusters at the proton reservoir interface provide a proton-coupled electron transfer mechanism, and conductive polymers provide a uniform potential distribution, inhibiting the initiation of zinc dendrites, inhibiting hydrogen evolution reaction, and inhibiting interface corrosion.

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