A zinc-iodine battery and electrode carrier capable of simultaneously inhibiting multiple iodine ion shuttling and regulating zinc deposition behavior

Abstract

This invention discloses a zinc-iodine battery and an electrode carrier that can simultaneously suppress polyiodine ion shuttle and regulate zinc deposition behavior, wherein the electrode carrier is Cu. + Coordinated poly(3,4-ethylenedioxythiophene) (Cu-PEDOT), via a solvothermal method, to convert Cu... + It was prepared by coordinating with S atoms in the PEDOT framework. I₂ was loaded onto this support as the positive electrode, and Zn was electrochemically deposited as the negative electrode to assemble a battery. The atomically monodisperse Cu in this invention... + It not only enhances the chemisorption of polyiodides as a Lewis active site, but also significantly reduces I... ‑ / I 0 Conversion energy barrier, accelerates reaction kinetics and suppresses shuttle effect; at the same time, Cu + The zinc-affinity property of the substrate reduces the Zn nucleation overpotential, guides Zn to deposit uniformly along the (002) crystal plane, and suppresses dendrites. Zinc-iodine batteries based on this substrate exhibit excellent rate performance and ultra-long cycle stability, and achieve dendrite-free negative electrode growth even under high depth-of-discharge conditions. This invention solves the problem of simultaneous multi-iodide shuttle in the positive electrode and zinc dendrite growth in the negative electrode using a single substrate, significantly improving the energy density and cycle life of the battery.

Description

Technical Field

[0001] This invention belongs to the field of zinc-iodine battery technology, specifically relating to a zinc-iodine battery and electrode carrier that can simultaneously suppress polyiodine ion shuttle and regulate zinc deposition behavior. Background Technology

[0002] In recent years, aqueous zinc-iodine batteries have gained popularity due to their high safety, abundant natural zinc and iodine resources, and the multi-electron conversion reactions involved in the iodine cathode (I0). - / I 0 Zinc-iodine batteries, with their advantages such as I0 properties, have become a research hotspot in the field of large-scale energy storage. Theoretically, zinc-iodine batteries, with their I0 properties, have become a research hotspot in the field of large-scale energy storage. - / I 0 The conversion can achieve 211 mAh g -1 Specific capacity and approximately 290 Wh kg -1 Its energy density demonstrates broad application prospects.

[0003] Despite the advantages mentioned above, the practical application of zinc-iodine batteries still faces a series of key challenges, specifically: (1) On the positive electrode side, the electronic conductivity of iodine species itself and its conversion product, elemental iodine, is extremely low (approximately 10). -6 ~10 -9 S cm -1 (2) In a typical aqueous electrolyte, I - / I 0 The conversion process does not occur directly and is highly susceptible to generating soluble intermediates (such as I3) during charging and discharging. - and I5 - These polyiodine ions easily shuttle to the zinc anode under the action of concentration gradient, and react with zinc metal, resulting in zinc anode corrosion, severe self-discharge effect and irreversible loss of active iodine material, which is the so-called "shuttle effect". (3) On the anode side, during repeated deposition / dissolution, due to uneven electric field distribution and insufficient nucleation sites, zinc metal is prone to uncontrollable zinc dendrite growth. In addition, water-induced hydrogen evolution reaction and by-product accumulation will further aggravate interface instability, which together affect the coulombic efficiency, safety and cycle life of the battery. (4) Due to the above problems, the utilization rate of zinc metal anode is usually low and it is difficult to work stably under high depth of discharge (DOD) conditions, which directly restricts the actual energy density of zinc-iodine batteries.

[0004] To address the issues on the positive electrode side, researchers have focused on loading active iodine onto support materials with high specific surface areas. Common supports include porous carbon materials, metal-organic frameworks (MOFs), and porous aromatic frameworks (PAFs), which can mitigate the diffusion of polyiodides to some extent through physical adsorption. Further introducing heteroatoms or polar functional groups into these materials can enhance chemisorption by utilizing the strong interactions between polar groups and iodine species, thereby more effectively suppressing the shuttle effect. However, these physical or chemisorption strategies have not fundamentally accelerated the diffusion of I-. - / I 0 The conversion reaction still cannot completely avoid soluble I3. - and I5 - The formation of intermediates. Recent studies have shown that carbon-based single-atom catalysts can significantly reduce I... - and I3 - The conversion energy barrier between them effectively inhibits the formation and shuttle of polyiodine intermediates from the perspective of catalytic conversion, and significantly accelerates the conversion of I... - / I 0 The conversion kinetics of traditional carbon materials are limited. However, the limited intrinsic conductivity of these materials restricts further improvement in their redox kinetics at high current densities. Meanwhile, to address the issues on the anode side, constructing anodes with zinc-affinity deposition supports is considered an effective strategy to guide uniform zinc nucleation and improve the adaptability of zinc anodes at high discharge depths. However, most reported alloy and carbon-based deposition supports have limited zinc-affinity sites or insufficient structural stability, and still cannot meet the long-cycle requirements under high discharge depths (e.g., above 50%).

[0005] In summary, the challenges faced by the positive and negative electrodes of zinc-iodine batteries are interconnected and mutually influential. Improvement strategies targeting only one electrode are insufficient to address the dual needs of both, thus limiting the overall performance improvement of zinc-iodine batteries. Therefore, there is an urgent need to develop a bifunctional carrier material that can simultaneously solve the problems of polyiodide shuttle in the positive electrode and dendrite growth and high DOD adaptability in the negative electrode. Summary of the Invention

[0006] The purpose of this invention is to solve the key technical problem of the simultaneous presence of positive and negative electrodes in zinc-iodine batteries, specifically including: slow kinetics of iodine species conversion on the positive electrode side, and soluble polyiodide ions (I3) - / I5 - To address the issues of active material loss and self-discharge caused by severe shuttle effect, uncontrolled growth of zinc dendrites on the negative electrode side, water-induced side reactions, and poor adaptability under high depth of discharge (DOD) conditions, this paper proposes a dual-functional carrier material that can simultaneously solve the problems of positive electrode polyiodide shuttle and negative electrode dendrite growth and high DOD adaptability.

[0007] To achieve the above objectives, the present invention provides a zinc-iodine battery electrode carrier that can simultaneously suppress polyiodine ion shuttle and regulate zinc deposition behavior, wherein the electrode carrier is Cu. + Coordinated poly(3,4-ethylenedioxythiophene), wherein Cu + Coordinated with the S atom on the thiophene ring, and Cu + It exists in an atomically monodisperse state.

[0008] Furthermore, the Cu + The preparation method of coordinated poly(3,4-ethylenedioxythiophene) is as follows: copper chloride is completely dissolved in ethanol, 3,4-ethylenedioxythiophene (EDOT) is added and mixed evenly, the resulting mixed solution is transferred to a reaction vessel with a polytetrafluoroethylene substrate, argon gas is introduced and the reaction is carried out at 80-120 °C for 20-30 h, washed with deionized water and ethanol and dried at 60-100 °C for 8-12 h.

[0009] Furthermore, the feeding ratio of copper chloride to 3,4-ethylenedioxythiophene is 100-300 mg: 100-300 μL.

[0010] The present invention also provides a zinc-iodine battery, wherein the positive electrode of the battery is made of the aforementioned Cu. + The battery is prepared by loading iodine onto a coordinated poly(3,4-ethylenedioxythiophene) carrier, and the negative electrode of the battery is made of the aforementioned Cu. + It was prepared by depositing zinc on a carrier of coordinated poly(3,4-ethylenedioxythiophene).

[0011] The above-mentioned positive electrode is prepared by: using iodine-loaded Cu... + Coordinated poly(3,4-ethylenedioxythiophene) is uniformly mixed with Ketjen black and polyvinylidene fluoride at a mass ratio of 7-9:1:1. N-methylpyrrolidone is added and stirred for 4-10 h to obtain a viscous slurry. The slurry is uniformly coated on a stainless steel mesh and vacuum dried at 30-50 °C for 8-12 h. The mesh is then stamped into a circular electrode.

[0012] Furthermore, the iodine-loaded Cu + The preparation method of coordinated poly(3,4-ethylenedioxythiophene) is as follows: Cu + Coordinated poly(3,4-ethylenedioxythiophene) and iodine were placed in a sealed container at a mass ratio of 1 to 3:1 and heated at 90 to 110 °C for 8 to 12 hours for iodine loading treatment. Subsequently, the adsorbed iodine was removed by heating at 50 to 70 °C for 1 to 2 hours in air.

[0013] The above-mentioned negative electrode is prepared by: Cu +A negative electrode carrier electrode was prepared by coating coordinated poly(3,4-ethylenedioxythiophene) onto a stainless steel mesh. This carrier electrode served as the working electrode, and a zinc foil of the same size as the counter electrode. A mixed aqueous solution containing ZnSO4, Na2SO4, and H3BO3 was used as the electrolyte. Electrolysis was carried out at 8–12 mAh / cm³. -2 Electrochemical deposition of zinc was performed by constant current discharge at a current density for 0.5–2 h, and the working electrode was rinsed with deionized water after deposition.

[0014] Furthermore, the concentration of ZnSO4 in the electrolyte is 1–3 mol / L. -1 The concentration of Na2SO4 is 0.5–2 mol / L. -1 The concentration of H3BO3 is 0.2–0.8 mol / L. -1 .

[0015] Furthermore, the method for preparing the negative electrode carrier electrode is as follows: Cu + Coordinated poly(3,4-ethylenedioxythiophene) and polyvinylidene fluoride are uniformly mixed at a mass ratio of 8 to 10:1. N-methylpyrrolidone is added and stirred for 4 to 10 hours to obtain a viscous slurry. The slurry is uniformly coated on a stainless steel mesh and vacuum dried at 30 to 50 °C for 8 to 12 hours. The mesh is then stamped into a circular electrode.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This invention introduces atomically monodisperse Cu on the backbone of the conductive polymer poly(3,4-ethylenedioxythiophene). + A cathode support possessing both catalytic activity and adsorption capacity was constructed. Cu in this support... + The sulfur atom coordinates with the sulfur atom on the thiophene ring, forming a stable single-atom active site. Experiments have shown that this structure can significantly reduce I... - / I 0 The energy barrier of the conversion reaction accelerates redox kinetics and enhances the chemisorption of polyiodide intermediates, thereby inhibiting I3 production at its source. - and I5 - The generation and shuttle of iodine-loaded Cu. + A battery was assembled using coordinated poly(3,4-ethylenedioxythiophene) as the positive electrode and bare zinc as the negative electrode, at 0.1 A g. -1 The following shows a capacity of 192 mAh g. -1 The initial discharge capacity was maintained at 89.4% after 100 cycles; at 5 A g -1 After 15,000 cycles at high current density, the capacity retention rate is still as high as 72.0%.

[0018] 2. This invention uses Cu +Coordinated poly(3,4-ethylenedioxythiophene) was used as the negative electrode support for zinc deposition, in which atomically dispersed Cu + As a highly efficient zinc-loving site, it can significantly reduce the nucleation overpotential of zinc, enabling uniform nucleation of zinc ions in the early stages of deposition. Meanwhile, Cu... + The introduction of this material induces zinc to preferentially deposit horizontally along the (002) crystal plane, effectively avoiding the formation of vertically growing zinc dendrites. A symmetric cell based on this support operates at 1 mA cm⁻¹. -2 and 0.5 mAh cm -2 Under certain conditions, it can cycle stably for more than 480 hours, and the electrode surface is smooth and dendrite-free. Under high discharge depth conditions of 50% and 60%, it can operate stably for 96 hours and 20 hours, respectively, which is significantly better than traditional zinc foil anodes.

[0019] 3. The Cu of the present invention + The coordinated poly(3,4-ethylenedioxythiophene) support was used in both the positive and negative electrodes, and the assembled Zn@Cu-PEDOT││I2@Cu-PEDOT full cells exhibited excellent overall performance. At 5 A g... -1 At a current density of 123 mAh g, the initial discharge capacity of the full battery is 123 mAh g. -1 It still maintains 80 mAh g after 4600 long cycles. -1 More importantly, by using this carrier as the negative electrode, the energy density of the full cell is more than twice that of the comparison cell using commercial zinc foil, due to the effective suppression of side reactions and improved zinc utilization. Attached Figure Description

[0020] Figure 1 These are SEM, TEM, and HADDF-STEM images of Cu-PEDOT prepared in Example 1.

[0021] Figure 2 The normalized curves of Cu K-edge XANES spectra of Cu-PEDOT prepared in Example 1 and standard samples (Cu2S, CuS and copper foil) are shown.

[0022] Figure 3 The Cu-PEDOT prepared in Example 1 and the PEDOT prepared in Comparative Example 1 were compared at 1.0 mV. -1 The CV curve below.

[0023] Figure 4 The cycle performance of zinc-iodine batteries using zinc foil as the negative electrode in Example 1 and Comparative Example 1 is shown.

[0024] Figure 5 These are the time-voltage curves and corresponding in-situ Raman spectra of zinc-iodine batteries using zinc foil as the negative electrode in Example 1 and Comparative Example 1.

[0025] Figure 6 The images show the XRD patterns of Cu-PEDOT prepared in Example 1 after deposition of different capacities of metallic zinc.

[0026] Figure 7 The cycling performance of the symmetrical cells in Example 1 and Comparative Example 1 is shown.

[0027] Figure 8 This is a Ragone diagram of the zinc-iodine batteries assembled using the Zn-Cu-P negative electrode in Example 1 and the Zn-P negative electrode in Comparative Example 1.

[0028] Figure 9 The cycle performance of the zinc-iodine batteries assembled using the Zn-Cu-P anode in Example 1 and the Zn-P anode in Comparative Example 1 is shown. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0030] Example 1

[0031] Cu + Preparation of coordinated poly(3,4-ethylenedioxythiophene) (Cu-PEDOT): 225 mg CuCl2·2H2O was added to 5 mL of anhydrous ethanol, and the mixture was sonicated for 10 min to obtain a clear solution. 200 μL of EDOT monomer was slowly added dropwise to the clear solution and sonicated for 5 min. The mixture was then transferred to a reaction vessel with a polytetrafluoroethylene substrate, and reacted at 100 °C for 24 h after purging with argon gas. The product was washed several times by centrifugation with deionized water and ethanol, and then vacuum dried at 60 °C for 10 h to obtain Cu-PEDOT. Figure 1 As can be seen, Cu-PEDOT exhibits a spherical particle morphology with a particle diameter of approximately 200 nm. Monodisperse Cu atoms are stably present in Cu-PEDOT, and no crystalline substances were observed. Figure 2 As can be seen, the CuK-edge XANES spectrum normalization curve of Cu-PEDOT differs from that of CuS, Cu2S, and copper foil, indicating that Cu atoms in Cu-PEDOT exhibit an atomic-level distribution. Simultaneously, the near-edge absorption position of Cu-PEDOT falls between that of copper foil and the CuS control sample, suggesting that the valence state of Cu in Cu-PEDOT is between 0 and +2.

[0032] Cu +Preparation of a coordinated poly(3,4-ethylenedioxythiophene) iodine-loaded (I2-Cu-P) cathode: 20 mg I2 and 40 mg Cu-PEDOT were mixed thoroughly and placed in a 5 mL sealed glass bottle. The mixture was heated at 100 °C for 10 h for iodine loading treatment. Subsequently, the open glass bottle was heated at 60 °C for 1 h to remove residual I2 molecules from the Cu-PEDOT surface, yielding iodine-loaded Cu-PEDOT. 40 mg of iodine-loaded Cu-PEDOT, 5 mg Ketjen Black, and 5 mg polyvinylidene fluoride were mixed, and 200 mL of N-methylpyrrolidone was added. The mixture was stirred to form a viscous slurry, which was then evenly coated onto a 200-mesh stainless steel mesh with a brush. The mesh was dried in a vacuum oven at 60 °C for 10 h and then stamped into a circular electrode with a diameter of 10 mm to obtain the I2-Cu-P cathode. The iodine loading on the I2-Cu-P cathode was 1.0 mg cm⁻¹. -2 .

[0033] Cu + Preparation of a coordinated poly(3,4-ethylenedioxythiophene) deposited zinc (Zn-Cu-P) anode: 45 mg Cu-PEDOT and 5 mg polyvinylidene fluoride were ground and mixed, and 100 mL N-methylpyrrolidone was added. The mixture was stirred to form a viscous slurry. The slurry was then evenly coated onto a 200-mesh stainless steel mesh with a brush. After drying in a vacuum oven at 60 °C for 10 h, the slurry was pressed into a circular electrode with a diameter of 10 mm to obtain the Cu-PEDOT electrode. Using the Cu-PEDOT electrode as the working electrode and a zinc foil of the same size as the counter electrode, a solution containing 2 mol L... -1 ZnSO4, 1 mol L -1 Na2SO4 and 0.4 mol L -1 A mixed aqueous solution of H3BO3 was used as the electrolyte, and a Whatman glass microfiber membrane (GF / D) was used as the separator. The electrolyte was measured at 10 mA cm⁻¹. -2 A constant current discharge was performed at a current density for 1 h to deposit metallic zinc onto the Cu-PEDOT electrode. The working electrode was then rinsed with a large amount of deionized water and dried to obtain a Zn-Cu-P negative electrode.

[0034] Assembly of Zinc-Iodine Batteries: Assemble the zinc-iodine batteries in air. The assembly sequence is: positive electrode shell, I₂-Cu-P positive electrode, glass fiber separator, and electrolyte (2 mol / L). -1 ZnSO4 aqueous solution), Zn-Cu-P negative electrode or zinc foil, gasket, spring, negative electrode shell, battery shell model CR2032 button cell, 120 μL of 2 mol L added to each cell. -1 ZnSO4 aqueous solution, glass fiber diaphragm model is Whatman glass microfiber membrane (GF / D).

[0035] Assembly of symmetrical cells: Assemble symmetrical cells in air. The assembly sequence is: Zn-Cu-P negative electrode, glass fiber membrane, electrolyte (2 mol L⁻¹). -1 ZnSO4 aqueous solution), Zn-Cu-P negative electrode, gasket, spring, negative electrode shell, battery shell model CR2032 coin cell, 120 μL of 2 mol L added to each cell. -1 ZnSO4 aqueous solution, glass fiber diaphragm model is Whatman glass microfiber membrane (GF / D).

[0036] Comparative Example 1

[0037] Preparation of poly(3,4-ethylenedioxythiophene) (PEDOT): 225 mg FeCl3·6H2O was added to 5 mL of anhydrous ethanol, and the mixture was sonicated for 10 min to obtain a clear solution. 200 μL of EDOT monomer was slowly added dropwise to the clear solution and sonicated for 5 min. The mixture was then transferred to a reaction vessel with a polytetrafluoroethylene substrate, and reacted at 100 °C for 24 h after purging with argon gas. The product was washed several times by centrifugation with deionized water and ethanol, and then vacuum dried at 60 °C for 10 h to obtain PEDOT.

[0038] Preparation of poly(3,4-ethylenedioxythiophene) iodine-loaded (I2-P) cathode: 20 mg I2 and 40 mg PEDOT were mixed evenly and placed in a 5 mL sealed glass bottle. The mixture was heated at 100 °C for 10 h for iodine loading treatment. Subsequently, the open glass bottle was heated at 60 °C for 1 h to remove residual I2 molecules on the PEDOT surface, obtaining iodine-loaded PEDOT. 45 mg of iodine-loaded PEDOT, 5 mg Ketjen Black, and 5 mg polyvinylidene fluoride were mixed, and 200 mL of N-methylpyrrolidone was added. The mixture was stirred to form a viscous slurry. The slurry was then evenly coated onto a 200-mesh stainless steel mesh with a brush and dried in a vacuum oven at 60 °C for 10 h. The resulting electrode was then stamped into a circular electrode with a diameter of 10 mm, yielding the I2-P cathode. The iodine loading on the I2-P cathode was 1.0 mg / cm³. -2 .

[0039] Preparation of poly(3,4-ethylenedioxythiophene) deposited (Zn-P) anode: 45 mg PEDOT and 5 mg polyvinylidene fluoride were ground and mixed, and 100 mL of N-methylpyrrolidone was added. The mixture was stirred to form a viscous slurry. The slurry was then evenly coated onto a 200-mesh stainless steel mesh with a brush. After drying in a vacuum oven at 60 °C for 10 h, the mesh was stamped into a circular electrode with a diameter of 10 mm to obtain the PEDOT electrode. Using the PEDOT electrode as the working electrode and a zinc foil of the same size as the counter electrode, a solution containing 2 mol / L... -1 ZnSO4, 1 mol L -1 Na2SO4 and 0.4 mol L -1 A mixed aqueous solution of H3BO3 was used as the electrolyte, and a Whatman glass microfiber membrane (GF / D) was used as the separator. The electrolyte was measured at 10 mA cm⁻¹. -2 A constant current discharge was performed at a current density for 1 hour to deposit metallic zinc onto the PEDOT electrode. The working electrode was then rinsed with a large amount of deionized water and dried to obtain a Zn-P negative electrode.

[0040] The zinc-iodine battery was assembled using the I2-P positive electrode and the Zn-P negative electrode according to the method in Example 1.

[0041] The Zn-P negative electrode was assembled into a symmetrical cell according to the method in Example 1.

[0042] To investigate the differences in redox reactions between the I2-Cu-P cathode prepared in Example 1 and the I2-P cathode prepared in Comparative Example 1, Figure 3 The zinc-iodine battery assembled using zinc foil in Example 1 and the zinc-iodine battery assembled in Comparative Example 1 are shown at 1.0 mV s. -1 The CV curves were obtained below. In Example 1, the zinc-iodine battery assembled using zinc foil showed a pair of distinct redox peaks at 1.28 V and 1.18 V, corresponding to the oxidation and reduction processes of I₂, respectively. Compared to the zinc-iodine battery assembled using zinc foil in Comparative Example 1, the zinc-iodine battery in Example 1 exhibited a higher current response and a smaller potential difference between the oxidation and reduction peaks, indicating higher specific capacity, lower polarization, and better reversibility. The zinc-iodine battery in Comparative Example 1, assembled using zinc foil, observed two consecutive oxidation peaks between 1.2 and 1.5 V, with the peak at a low potential of 1.29 V corresponding to I₂ oxidation. - Convert to I3 - The oxidation process, the peak at a high potential of 1.42 V corresponds to I3. - Convert to I 0 The oxidation process. In Example 1, the zinc-iodine battery assembled using zinc foil did not show the aforementioned I3. - Oxidized to I 0This step indicates that the oxidation reaction of I2 proceeds rapidly on the Cu-PEDOT prepared in Example 1, thereby significantly suppressing the I3 oxidation reaction on the positive electrode side. - / I5 - The accumulation of intermediates reduces the shuttle of polyiodides.

[0043] To further confirm that the I2-Cu-P cathode prepared in Example 1 is beneficial for achieving a highly stable zinc-iodine battery, Figure 4 The zinc-iodine battery assembled using zinc foil in Example 1 and the zinc-iodine battery assembled using zinc foil in Comparative Example 1 are shown at 0.1 A g. -1 Cycling performance curves at a current density of 100 cycles. Example 1: Zinc-iodine battery assembled using zinc foil; Comparative Example 1: Zinc-iodine battery assembled using zinc foil; Cycling performance curves at 0.1 A g. -1 Under the conditions, it showed 192 mAh g -1 and 130 mAh g -1 The initial capacity remained at 171 mAh g after 100 cycles. -1 and 71 mAh g -1 The capacity retention rates were 89.1% and 54.6%, respectively, indicating that the Cu-PEDOT iodine-loaded cathode exhibits excellent reversibility and cycle stability.

[0044] To demonstrate that the Cu-PEDOT support enables rapid I2 conversion, the evolution of iodine species on the cathode side was monitored using in-situ Raman spectroscopy. Figure 5 As can be seen, the Raman spectrum of the zinc-iodine battery assembled using zinc foil in Comparative Example 1 during the charge and discharge process is at 108 cm⁻¹. -1 and 164 cm -1 Two strong peaks are observed at the wavenumber, which correspond to the intermediate state I3. - and I5 - The symmetrical stretching and contracting vibration band is mainly generated by I. - Side reactions triggered by the slow reaction kinetics between I2 and I2 (I - + I2 → I3 - I3 - + I2 → I5 - Specifically, during the initial charging phase (point A), the intensity of these two vibration bands gradually increases, reaching a peak at full charge (point B), reflecting I... - Gradually oxidized to I3 - (converted to I5) - The process of the intermediate state before. Subsequently, during the discharge process from point B to point D, due to the continuous reduction process (I5) - → I3 - → I -The vibration band intensity continued to decrease and eventually disappeared. In contrast, the Raman spectrum of the zinc-iodine battery assembled using zinc foil in Example 1 showed only extremely weak I3 during the charge and discharge process. - and I5 - The signal peak indicates that the concentration of polyiodide generated on the I2-Cu-P cathode side is extremely low, and Cu + Coordination can promote I - / I 0 Rapid conversion.

[0045] To investigate the effect of Cu-PEDOT prepared in Example 1 on Zn deposition behavior, Cu-PEDOT prepared in Example 1 was subjected to deposition at 10 mA cm⁻¹. -2 XRD analysis was performed after depositing metallic zinc of different capacities at varying current densities. Figure 6 As can be seen, the zinc metal deposited on the Cu-PEDOT prepared in Example 1 exhibits obvious diffraction peaks at 36.2°, 38.9°, and 43.2°, which correspond to the (002), (100), and (101) crystal planes of the densest hexagonal zinc packing, respectively. When the deposition capacities are 2, 4, 6, 8, and 10 mAh cm⁻¹, the diffraction peaks are observed. -2 When, the ratio of the intensity of the (002) crystal plane diffraction peak to the intensity of the (100) crystal plane diffraction peak (I (002) / I (100) The values ​​were 1.29, 1.54, 1.60, 1.78 and 1.84, respectively, which indicates that the zinc metal deposited on the Cu-PEDOT electrode prepared in Example 1 tends to expose more (002) crystal planes.

[0046] To investigate the Zn utilization efficiency of the Zn-Cu-P anode prepared in Example 1, the symmetrical cell assembled in Example 1 and the symmetrical cell assembled in Comparative Example 1 were subjected to cycle tests at different depths of discharge. Figure 7 As can be seen, the cycle times of the symmetrical cell assembled in Example 1 at 30%, 40%, 50%, and 60% discharge depths were 140 h, 110 h, 96 h, and 20 h, respectively, while the cycle times of the symmetrical cell assembled in Comparative Example 1 at 30%, 40%, 50%, and 60% discharge depths were 22 h, 9 h, 6 h, and 3 h, respectively. Example 1 is significantly superior to the symmetrical cell assembled in Comparative Example 1. This indicates that the coordinated Cu... + It provides abundant nucleation sites, ensuring the uniformity of Zn deposition and enabling symmetric cells to maintain stable deposition / dissolution behavior even at high discharge depths.

[0047] Depend on Figure 8As can be seen, the energy density and power density of the zinc-iodine battery assembled in Example 1 were calculated based on the total mass of the active material and the carrier. The energy density of the zinc-iodine battery assembled using a Zn-Cu-P negative electrode in Example 1 was 8.38 Wh / kg. -1 The zinc-iodine battery assembled using zinc foil in Example 1 has an energy density of 3.58 Wh kg. -1 This indicates that replacing zinc foil with Zn-Cu-P negative electrode can double the energy density of zinc-iodine batteries.

[0048] To verify that the Cu-PEDOT prepared in Example 1 can serve as both the positive and negative electrode carrier in a zinc-iodine battery, the zinc-iodine battery assembled in Example 1 using a Zn-Cu-P negative electrode was tested at 5 A g. -1 Cyclic performance tests were conducted at current densities. Figure 9 As can be seen, the zinc-iodine battery assembled using a Zn-Cu-P negative electrode in Example 1 initially had a capacity of 123 mAh g⁻¹. -1 The capacity has 80 mAh g after 4600 cycles. -1 The capacity. Comparative Example 1, a zinc-iodine battery assembled using a Zn-P negative electrode, initially had a capacity of 109 mAhg. -1 The battery failed after 500 cycles, indicating that the I2-Cu-P cathode accelerated the I2-Cu-P degradation. - / I 0 By converting and inhibiting the formation of polyiodides, the Zn-Cu-P anode can achieve rapid nucleation and guide uniform Zn deposition. Under the combined effect of these two factors, the electrochemical performance of zinc-iodine batteries is significantly improved.

Claims

1. A zinc-iodine battery electrode carrier capable of simultaneously suppressing polyiodine ion shuttle and regulating zinc deposition behavior, characterized in that: The carrier is Cu + Coordinated poly(3,4-ethylenedioxythiophene), wherein Cu + Coordinated with the S atom on the thiophene ring, and Cu + It exists in an atomically monodisperse state.

2. The zinc-iodine battery electrode carrier according to claim 1, which can simultaneously suppress polyiodine ion shuttle and regulate zinc deposition behavior, is characterized in that: The Cu + The preparation method of coordinated poly(3,4-ethylenedioxythiophene) is as follows: copper chloride is completely dissolved in ethanol, 3,4-ethylenedioxythiophene is added and mixed evenly, the resulting mixed solution is transferred to a reaction vessel with a polytetrafluoroethylene substrate, argon gas is introduced and the reaction is carried out at 80-120 °C for 20-30 h, washed with deionized water and ethanol and dried at 60-100 °C for 8-12 h.

3. The zinc-iodine battery electrode carrier according to claim 2, which can simultaneously suppress polyiodine ion shuttle and regulate zinc deposition behavior, is characterized in that: The feeding ratio of copper chloride to 3,4-ethylenedioxythiophene is 100-300 mg: 100-300 μL.

4. A zinc-iodine battery, characterized in that: The positive electrode of the battery is made of Cu as described in claim 1. + The battery is prepared by loading iodine onto a coordinated poly(3,4-ethylenedioxythiophene) carrier, and the negative electrode of the battery is made of Cu as described in claim 1. + It was prepared by depositing zinc on a carrier of coordinated poly(3,4-ethylenedioxythiophene).

5. The zinc-iodine battery according to claim 4, characterized in that: The positive electrode is prepared by: loading iodine-containing Cu... + Coordinated poly(3,4-ethylenedioxythiophene) is uniformly mixed with Ketjen black and polyvinylidene fluoride at a mass ratio of 7-9:1:

1. N-methylpyrrolidone is added and stirred for 4-10 h to obtain a viscous slurry. The slurry is uniformly coated on a stainless steel mesh and vacuum dried at 30-50 °C for 8-12 h. The mesh is then stamped into a circular electrode.

6. The zinc-iodine battery according to claim 5, characterized in that: The iodine-loaded Cu + The preparation method of coordinated poly(3,4-ethylenedioxythiophene) is as follows: Cu + Coordinated poly(3,4-ethylenedioxythiophene) and iodine were placed in a sealed container at a mass ratio of 1 to 3:1 and heated at 90 to 110 °C for 8 to 12 h, followed by heating in air at 50 to 70 °C for 1 to 2 h.

7. The zinc-iodine battery according to claim 4, characterized in that: The method for preparing the negative electrode is as follows: Cu + A negative electrode carrier electrode was prepared by coating coordinated poly(3,4-ethylenedioxythiophene) onto a stainless steel mesh. This carrier electrode served as the working electrode, and a zinc foil of the same size as the counter electrode. A mixed aqueous solution containing ZnSO4, Na2SO4, and H3BO3 was used as the electrolyte. Electrolysis was carried out at 8–12 mAh / cm³. -2 Electrochemical deposition of zinc was performed by constant current discharge at a current density for 0.5–2 h, and the working electrode was rinsed with deionized water after deposition.

8. The zinc-iodine battery according to claim 7, characterized in that: The concentration of ZnSO4 in the electrolyte is 1–3 mol / L. -1 The concentration of Na2SO4 is 0.5–2 mol / L. -1 The concentration of H3BO3 is 0.2–0.8 mol / L. -1 .

9. The zinc-iodine battery according to claim 7, characterized in that: The method for preparing the negative electrode carrier electrode is as follows: Cu + Coordinated poly(3,4-ethylenedioxythiophene) and polyvinylidene fluoride are uniformly mixed at a mass ratio of 8 to 10:

1. N-methylpyrrolidone is added and stirred for 4 to 10 hours to obtain a viscous slurry. The slurry is uniformly coated on a stainless steel mesh and vacuum dried at 30 to 50 °C for 8 to 12 hours. The mesh is then stamped into a circular electrode.

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