Zinc iodide-fullerene chloride composite positive electrode material and preparation method thereof

Abstract

This invention provides a zinc iodide-fullerene chloride composite cathode material and its preparation method. The preparation method comprises the following steps: Step 1: Zinc iodide, fullerene chloride, and a conductive agent are added to a quartz mortar in proportion and ground thoroughly; Step 2: A dispersant is added to the ground composite powder and continuously stirred to form a slurry with uniform component distribution; Finally, a binder is added to the slurry and further stirred; During the stirring process, the gradual volatilization of the dispersant promotes the increase of the solid content of the system, causing the mixture to gradually change from a slurry state to a semi-dry agglomerate until there is no obvious solid adhesion on the side wall of the container; Step 3: The obtained semi-dry agglomerate is formed into a film by a roll forming process, and then the film is subjected to pressure compaction treatment; The compacted film is placed in a vacuum oven for vacuum drying to completely remove residual dispersant, and finally a dry and dense self-supporting zinc iodide-fullerene chloride composite cathode film is obtained.

Description

Technical Field

[0002] This invention relates to the field of aqueous zinc-iodine battery technology, specifically to zinc iodide-fullerene chloride composite cathode material and its preparation method. Background Technology

[0004] Currently, aqueous zinc-iodine batteries have become an important research direction in the energy storage field in recent years due to their advantages such as high safety, environmental friendliness, abundant raw material reserves, and low manufacturing costs. Zinc accounts for approximately 0.0075% of the Earth's crust, while iodine content in seawater is approximately 50–60 μg / L, making resources widely available and easily accessible. Furthermore, aqueous zinc-iodine batteries also possess high theoretical specific capacity (approximately 820 mAh / g for the zinc anode and approximately 211 mAh / g for the iodine cathode) and a voltage rating of approximately 1.3 V (vs Zn). 2+ The discharge plateau voltage of / Zn) is therefore considered to have good application potential in the field of large-scale energy storage.

[0005] Despite this, existing aqueous zinc-iodine batteries still face several key technical bottlenecks in practical applications. First, elemental iodine and its conversion products have poor electronic conductivity, easily leading to slow reaction kinetics at the positive electrode interface, making it difficult to achieve rapid, stable, and reversible redox reactions under high loading conditions. Second, during battery charging and discharging, I3 is typically generated within the system. - I5 - The presence of polyiodide intermediates in aqueous electrolytes leads to their easy dissolution and further diffusion and migration, resulting in a significant shuttle effect. This phenomenon not only causes continuous loss of active iodine components but may also induce zinc anode corrosion and side reactions, leading to problems such as accelerated battery self-discharge, increased capacity decay rate, and decreased coulombic efficiency, ultimately affecting the cycle life and long-term stability of aqueous zinc-iodine batteries.

[0006] To address the aforementioned issues, existing technologies typically employ porous carbon materials as carriers or conductive frameworks for iodine-based active substances to construct iodine-based composite cathode systems. Due to their high specific surface area, well-developed pore structure, and excellent electronic conductivity, porous carbon materials facilitate the establishment of a continuous electron transport network within the electrode and improve electrolyte wettability and ion diffusion behavior, thereby enhancing the utilization rate of iodine active substances and the overall electrochemical performance of the battery to a certain extent.

[0007] However, the application of porous carbon materials in existing iodine-based cathode systems still has certain limitations, including the following aspects:

[0008] (1) Existing porous carbon materials mainly rely on pore structure confinement and physical adsorption to act on iodine and polyiodides, and their ability to chemically fix iodine species is relatively limited. Under long-term cycling or high loading conditions, it is still difficult to effectively inhibit the dissolution, diffusion and migration of polyiodides, resulting in continuous loss of active materials, thereby limiting the further improvement of battery cycle stability (Journal of Energy Storage 2024, 84, 110765. DOI: 10.1016 / j.est.2024.110765).

[0009] (2) There is still room for further optimization of the dispersion uniformity between existing porous carbon materials and iodine-based active substances. Currently, wet or dry processes are mostly used to achieve the composite of the two, but the relevant processes still have certain defects. For example, when Zhang et al. used the wet electrode preparation process, there were problems such as easy volatilization of iodine, limited loading of active material, low electrode compaction density, and obvious shuttle effect of polyiodides (Advanced Materials 2022, 34 (23), e2201716. DOI:10.1002 / adma.202201716); the dry preparation process proposed by Wu et al. alleviated the problems of insufficient iodine loading, easy sublimation of iodine, and limited large-scale preparation to a certain extent, but it was prone to local heat accumulation during PTFE fiberization, which caused some iodine sublimation loss and further affected the utilization rate of active material (Joule 2025, 9 (7), 102000.DOI: 10.1016 / j.joule.2025.102000).

[0010] Therefore, while maintaining the good electronic conductivity and structural stability of the cathode system, how to further improve the uniform dispersion and stable fixation of iodine-based active materials, especially to achieve long-term effective confinement of iodine species and inhibit their migration and diffusion under high load conditions, remains an important technical problem that urgently needs to be solved in this field. Summary of the Invention

[0012] To address the problems of insufficient conductivity of iodine-based active materials, severe polyiodide shuttle effect, and poor cycle stability under high loading conditions in existing aqueous zinc-iodine batteries, this invention provides a zinc iodide-fullerene chloride composite cathode material and its application. By introducing fullerene chloride into the zinc iodide cathode system, stable anchoring and interface control of polyiodides are achieved, thereby improving the cycle performance and capacity performance of aqueous zinc-iodine batteries under high loading conditions.

[0013] The present invention adopts the following technical solution:

[0014] A zinc iodide-fullerene chloride composite cathode material, characterized in that it comprises: zinc iodide and fullerene chloride, wherein the fullerene chloride has the molecular formula:

[0015] C 60 Cl6,

[0016] A method for preparing a zinc iodide-fullerene chloride composite cathode, characterized by comprising the following steps:

[0017] Step 1: Zinc iodide, fullerene chloride, and a conductive agent are added to a quartz mortar in a specific ratio and ground thoroughly to obtain a fine composite powder. Step 2: A dispersant is added to the composite powder and continuously stirred to form a slurry with uniform component distribution. A binder is then added to the slurry and stirred further. During stirring, the gradual volatilization of the dispersant increases the solid content of the system, causing the mixture to gradually transform from a slurry state to a semi-dry agglomerate until no obvious solid adheres to the container sidewalls. Step 3: The obtained semi-dry agglomerate is rolled into a film using a roll forming process, followed by pressure compaction. The compacted film is then placed in a vacuum oven for vacuum drying to completely remove residual dispersant, ultimately obtaining a dry and dense self-supporting zinc iodide-fullerene chloride composite cathode film.

[0018] Furthermore, the total mass fraction of zinc iodide, fullerene chloride, conductive agent and binder in the slurry is 50-90%, and the mass ratio of the four is (10-85):(5-10):(5-40):(5-40).

[0019] Furthermore, the conductive agent in step one is at least one of activated carbon, carbon black, carbon nanotubes, graphite, and graphene.

[0020] Furthermore, the dispersant in step two is at least one of methanol, ethanol, isopropanol, and n-butanol.

[0021] Furthermore, the adhesive in step two is at least one of polytetrafluoroethylene, polyvinylidene fluoride, sodium carboxymethyl cellulose, and styrene-butadiene rubber.

[0022] Furthermore, the vacuum drying time in step three is 12–24 h.

[0023] Furthermore, the thickness of the self-supporting composite cathode film in step three is 50–1000 μm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The carbon atoms in the existing porous carbon framework are mainly sp. 2 and sp 3The hybrid orbitals exist, but their interaction with polyiodide anions is weak, mainly relying on surface physical adsorption induced by van der Waals forces and the physical confinement effect of pores. In contrast, the fullerene C chloride used in this invention... 60 The Cl6 molecule's unique geometric curvature causes the C–C bonds to bend, resulting in the sp orbitals of the carbon atoms becoming more hybridized. 2 with sp 3 The non-standard state between these states. This special electronic structure endows the fullerene chloride molecule with significant electron acceptor properties, enabling it to interact with polyiodide anions through charge transfer. The strength of this interaction far exceeds the physical adsorption energy of traditional porous carbon materials, thereby enhancing the anchoring effect on iodine-based active materials at the molecular level, effectively suppressing the loss of active materials, and significantly improving the capacity performance of the battery (Cell Reports Physical Science 2021, 2 (12), 100646. DOI: 10.1016 / j.xcrp.2021.100646).

[0026] (2) With unfunctionalized fullerene C 60 In comparison, the fullerene C chloride used in this invention 60 When chlorine atoms are introduced into some carbon atoms of the Cl6 molecule, its π-conjugated system is disrupted to some extent, resulting in a decrease in the overall electron delocalization ability of the material and a reduction in conductivity. However, C 60 The polar C–Cl bonds and surface chlorine functional groups in Cl6 enhance the interaction between it and polyiodide species, which is more conducive to the anchoring of polyiodides. This effectively inhibits the diffusion and migration of polyiodides in the electrolyte and improves the cycle performance of the battery. In addition, the increased surface polarity after chlorination modification can weaken the strong π–π stacking interaction between fullerene molecules, which is beneficial for constructing a uniform and stable composite cathode structure, resulting in better dispersion uniformity in the zinc iodide system.

[0027] (3) In the application of the zinc iodide-fullerene chloride composite cathode material of this patent, the present invention gradually mixes and stirs the zinc iodide-fullerene chloride composite material, conductive agent, binder and dispersant, so that the system forms a semi-dry agglomerate and is directly rolled and molded, which greatly improves the loading of active material in the cathode. At the same time, the rolling process gives the electrode a higher compaction density, which optimizes the charge transport path and enhances the structural integrity of the electrode, providing reliable technical support for the large-scale practical application of aqueous zinc-iodine batteries. Attached Figure Description

[0029] Figure 1 C 60 Optical photograph of the positive electrode film of the Cl6-0-80 blank sample.

[0030] Figure 2 C 60 Optical photograph of the positive electrode thin film of the Cl6-0.1-80 target sample.

[0031] Figure 3 For C 60 UV-Vis absorption spectrum of electrolyte in Cl6-0-80 electrolytic cell.

[0032] Figure 4 For C 60 UV-Vis absorption spectrum of electrolyte in an electrolytic cell with a temperature range of -0.1 to 80°C.

[0033] Figure 5 For C 60 UV-Vis absorption spectrum of electrolyte in Cl6-0.1-80 electrolytic cell.

[0034] Figure 6 For C 60 Cl6-0-80, C 60 -0.1-80 and C 60 The peak absorbance of the electrolyte at 360 nm in an electrolytic cell of Cl6-0.1-80.

[0035] Figure 7 C 60 Cl6-0-80 is used for the discharge voltage-discharge specific capacity curve of zinc-iodine batteries.

[0036] Figure 8 C 60 Cl6-0-80 was used to measure the discharge specific capacity-cycle count curve and capacity retention-cycle count curve of zinc-iodine batteries.

[0037] Figure 9 C 60 -0.1-80 Discharge voltage-discharge specific capacity curves for zinc-iodine batteries.

[0038] Figure 10 C 60 -0.1-80 is used for the discharge specific capacity-cycle number curve and capacity retention-cycle number curve of zinc-iodine batteries.

[0039] Figure 11 C 60 Cl6-0.1-80 is used for the discharge voltage-discharge specific capacity curve of zinc-iodine batteries.

[0040] Figure 12 C 60 Cl6-0.1-80 is used for the discharge specific capacity-cycle number curve and capacity retention-cycle number curve of zinc-iodine batteries. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0043] Example 1

[0044] In this embodiment, the positive electrode thin film preparation process is as follows:

[0045] (1) C 60 Preparation of the target sample positive electrode film Cl6-0.1-80: Ethanol was used as a dispersant to mix zinc iodide (ZnI2) and fullerene chloride (C6-0.1-80). 60 Zinc iodide (C16), activated carbon (AC), and polytetrafluoroethylene (PTFE) were mixed in a mass ratio of 72:8:10:10. First, zinc iodide, fullerene chloride, and activated carbon were thoroughly ground and mixed in a quartz mortar to obtain a fine powder. Then, an appropriate amount of ethanol was added and stirred to form a homogeneous slurry. Finally, PTFE emulsion was added. As stirring continued, the dispersant in the system gradually decreased, causing the mixture to transform from a thin slurry to a concentrated state. After the slurry transformed into a semi-dry agglomerate with no sidewall adhesion, it was rolled into shape using a roller press (roller gap set to 1 mm). The resulting film was wrapped with filter paper and further compacted in a fixture, then dried in a 45°C vacuum oven for 12 h to remove residual dispersant. Finally, a dry and dense self-supporting positive electrode film was obtained and cut into electrode sheets with a diameter of 8 mm for later use. The zinc iodide loading in the film was determined to be 50-55 mg / cm³. 2 .

[0046] (2) C 60 Preparation of the -0.1-80 comparative sample positive electrode film: The preparation process and proportions are the same as above, the only difference being the use of unmodified fullerene (C 60 ) to replace fullerene chloride (C 60 Cl6). The zinc iodide loading of the finally cut electrode sheets also remained at 50-55 mg / cm³. 2 Within the range.

[0047] (3) C 60 Preparation of the positive electrode film for the Cl6-0.1-80 blank sample: Using the same process, zinc iodide, activated carbon (AC), and polytetrafluoroethylene (PTFE) were mixed at a mass ratio of 80:10:10. The zinc iodide loading of the final cut electrode was maintained at 50-55 mg / cm³. 2 Within the range.

[0048] like Figure 1 and Figure 2 As shown, C 60 Optical photographs of the positive electrode film of the Cl6-0-80 blank sample and C60 Optical photographs of the positive electrode film of the Cl6-0.1-80 target sample. Macroscopically, both are self-supporting films with uniform texture.

[0049] In this embodiment, the polyiodide shuttle behavior during the charging and discharging process is monitored using ultraviolet-visible absorption spectroscopy:

[0050] Assemble the zinc-iodine quartz electrolytic cell: Using 2M ZnSO4 as the electrolyte, fix the above-mentioned positive electrode film and zinc negative electrode on opposite sides of a quartz cuvette. Charge-discharge tests were conducted at a mass current density of 100 mA / g and a voltage window of 0.6–1.6 V, and spectral signals in the range of 250–500 nm were acquired simultaneously.

[0051] Analysis of experimental results: such as Figure 3 , 4 As shown in Figure 5, I3 in the three electrolytic cell systems - The intensity of the characteristic absorption peaks (at 292 nm and 360 nm) gradually increases with the charging and discharging process; such as Figure 6 As shown, during the charging and discharging process, based on C 60 I3 in an electrolytic cell with Cl6-0.1-80 - The peak absorbance increased from 0.0937 (day 1) to 0.5708 (day 7), based on C 60 I3 in an electrolytic cell of -0.1-80°C - The peak absorbance increased from 0.0921 (day 1) to 1.077 (day 7), based on C 60 I3 in a Cl6-0-80 electrolytic cell - The peak absorbance increased from 0.1058 (day 1) to 2.0709 (day 7); compared with the blank sample and the control sample, the target sample increased I3 on ​​day 7. - Peak intensities decreased by 72.44% and 47.99% respectively, effectively reducing I3 during charging and discharging. - The dissolution and diffusion behavior of C in the electrolyte. This indicates that C 60 Cl6 has a stronger polyiodide anchoring ability, which can effectively constrain the dissolution and diffusion of polyiodides in the electrolyte.

[0052] In this embodiment, the performance of the battery assembled with the positive electrode film is tested as follows:

[0053] (1) Assembly of Zinc-Iodine Button Cells: In this embodiment, the assembly of zinc-iodine button cells was completed under an air atmosphere, using the CR2032 type battery. The specific assembly structure started from the negative electrode shell, and the spring sheet, gasket, zinc negative electrode, glass fiber separator, positive electrode film, and positive electrode shell were stacked sequentially from bottom to top. The zinc negative electrode had a thickness of 200 μm, and the separator was made of Whatman GF / D (thickness: 675 μm). Before encapsulation, 200 μL of 2M ZnSO4 electrolyte was injected into the system to ensure that the separator and electrode materials were fully wetted. After all components were arranged, mechanical sealing was performed using a sealing machine to finally obtain the zinc-iodine button cell to be tested.

[0054] (2) Electrochemical performance test: The theoretical capacity and long-term cycle stability of the above coin cells were tested by constant current charge-discharge test. The cutoff voltage window was set to 0.6–1.6 V, and the mass current density during the test was uniformly set to 100 mA / g.

[0055] like Figure 7 As shown, during the cyclic charge and discharge process, based on C 60 The specific discharge capacities of the Cl6-0-80 zinc-iodine battery in the 1st, 50th, 500th, and 911th cycles were 157.42 mAh / g, 150.37 mAh / g, 144.75 mAh / g, and 125.92 mAh / g, respectively. Figure 8 As shown, based on the first-cycle discharge specific capacity, and using C... 60 The specific capacity retention rates of the Cl6-0-80 zinc-iodine battery after 50, 500, and 911 cycles were 95.52%, 91.95%, and 79.99%, respectively. Figure 9 As shown, during the cyclic charge and discharge process, based on C 60 The discharge specific capacities of the -0.1-80 zinc-iodine battery in the 1st, 50th, 500th, 1000th, 2000th, 3000th, 4000th, and 5000th cycles are 165.66 mAh / g, 165.18 mAh / g, 160.59 mAh / g, 157.71 mAh / g, 155.18 mAh / g, 152.4 mAh / g, 146.33 mAh / g, and 142.91 mAh / g, respectively. Figure 10 As shown, based on the first-cycle discharge specific capacity, and using C... 60 The discharge specific capacity retention rates of the -0.1-80 zinc-iodine battery after 50, 500, 1000, 2000, 3000, 4000, and 5000 cycles are 99.71%, 96.94%, 95.2%, 93.67%, 91.99%, 88.33%, and 86.27%, respectively. Figure 11As shown, during the cyclic charge and discharge process, based on C 60 The specific discharge capacities of the Cl6-0.1-80 zinc-iodine battery in the 1st, 50th, 500th, 1000th, 2000th, 3000th, 4000th, and 5000th cycles are 178.84 mAh / g, 176.45 mAh / g, 173.61 mAh / g, 171.22 mAh / g, 169.26 mAh / g, 164.73 mAh / g, 161.87 mAh / g, and 159.39 mAh / g, respectively. Figure 12 As shown, based on the first-cycle discharge specific capacity, and using C... 60 The specific capacity retention rates of the Cl6-0.1-80 zinc-iodine battery after 50, 500, 1000, 2000, 3000, 4000, and 5000 cycles were 98.66%, 97.66%, 97.08%, 94.64%, 92.11%, 90.51%, and 89.12%, respectively. (Based on C...) 60 Cl6-0-80, C 60 -0.1-80 and C 60 The initial discharge specific capacities of the C16-0.1-80 zinc-iodine battery were 157.42 mAh / g, 165.66 mAh / g, and 178.84 mAh / g, respectively. Regarding the initial discharge specific capacity, C... 60 Cl6-0.1-80 compared to C 60 -0.1-80, an increase of 7.37%, C 60 Cl6-0.1-80 compared to C 60 The Cl6-0-80 increased by 11.98%, indicating that C 60 The target sample positive electrode film of Cl6-0.1-80 has the advantage of improving capacity performance. Using a discharge specific capacity retention rate of less than 80% as the criterion for battery failure, C... 60 The zinc-iodine battery with Cl6-0-80 retained 79.99% of its discharge specific capacity after 911 cycles, and its cycle life was less than 1000 cycles; C 60 The zinc-iodine battery with a discharge specific capacity retention of 86.27% after 5000 cycles (-0.1-80) has a cycle life exceeding 5000 cycles; C 60 The zinc-iodine battery with Cl6-0.1-80 exhibits a discharge specific capacity retention rate of 89.12% after 5000 cycles, indicating a cycle life exceeding 5000 cycles. Regarding the discharge specific capacity retention rate after 5000 cycles, C... 60 Cl6-0.1-80 compared to C 60 -0.1-80 increased by 2.85%, which indicates that C 60The Cl6-0.1-80 target sample cathode film exhibits a significant advantage in improving cycle performance. Battery capacity and cycle performance test results show that, compared to C... 60 Cl6-0-80 blank sample positive electrode film and C 60 -0.1-80 Comparison sample positive electrode film, C 60 The target sample cathode film of Cl6-0.1-80 has the advantage of improving capacity performance and cycle performance.

[0056] Based on the combined results of ultraviolet-visible absorption spectroscopy and battery charge-discharge performance tests, and using the content disclosed in this patent, C was prepared. 60 The target sample positive electrode film of Cl6-0.1-80 has the advantages of suppressing the polyiodide shuttle effect, improving battery capacity and cycle performance.

[0057] Li et al. proposed a porous nitrogen-doped carbon (NC) host strategy derived from metal-organic frameworks (MOFs). Through the synergistic effect of graphite-N and pyridine-N, active sites are formed, enabling the adsorption and catalytic conversion of polyiodides. This effectively suppresses the shuttle effect and improves the cycle stability of zinc-iodine batteries (Advanced Science 2025, 12 (26), 2502563. DOI: 10.1002 / advs.202502563). Although this study achieved a long lifetime of tens of thousands of cycles, the main achievement was at 1 mg / cm³. 2 The electrochemical performance of the material was evaluated under low loading conditions. This invention directly introduces chlorinated fullerene-based active materials into the cathode system, eliminating the need for complex metal-organic framework (MOF)-derived hierarchical porous structures. The unique electron acceptor properties of chlorinated fullerenes enable the confinement and regulation of polyiodides, and the excellent dispersibility of chlorinated fullerenes promotes the uniform distribution of zinc iodide active components, improving the uniformity of electrode interface reactions. Crucially, the cathode system constructed in this invention maintains extremely high stability even with iodine-based active material loadings as high as 50-55 mg / cm², significantly exceeding conventional loading levels reported in existing literature, greatly enhancing the practical value of the electrode. Furthermore, after 5000 cycles, the system retains a high capacity retention rate, demonstrating excellent cycle stability. Therefore, compared to reported technologies, the technology disclosed in this patent exhibits significant advantages for cathode films with high active material loadings, and pouch cells assembled based on this technology have potentially superior energy density.

[0058] In summary, this invention provides a zinc iodide-fullerene chloride composite cathode material and its application, achieved by directly introducing fullerene chloride (C) into the cathode system. 60Cl6) was used as a functional active component, and combined with a high-loading roll forming process, an iodine-based cathode system was constructed that combines the high efficiency of multi-iodide confinement, high solid density, and long-cycle stability, with the following beneficial effects:

[0059] On the one hand, compared to traditional porous carbon materials that mainly rely on van der Waals forces and pore confinement to physically adsorb polyiodides, the fullerene chloride C used in this invention... 60 Due to its unique curved carbon cage structure and non-standard hybrid electronic state, the Cl6 molecule exhibits significant electron acceptor characteristics. It can form a strong charge transfer interaction with polyiodide anions, thereby enhancing the anchoring ability of iodine-based active materials at the molecular level. This effectively inhibits the dissolution, migration, and shuttle behavior of polyiodides during charge and discharge, reduces the loss of active materials, and improves the capacity performance of the battery.

[0060] On the other hand, with unfunctionalized fullerene C 60 In comparison, fullerene chloride C 60 The polar C–Cl bonds and chlorine functional groups on the surface of Cl6 molecules can further enhance the interfacial interaction between them and polyiodine species, while weakening the π–π stacking effect between fullerene molecules. This improves the dispersion uniformity of the material in the cathode system, which is beneficial for constructing a structurally stable and uniformly reacting composite cathode network. Furthermore, the present invention employs a composite slurry stepwise mixing and roll forming process, which can significantly increase the active material loading and electrode compaction density. This shortens the electron / ion transport path while enhancing the electrode structural integrity, thus maintaining excellent cycling stability under high loading and long cycling conditions.

[0061] In summary, this invention achieves effective regulation of polyiodide migration behavior and significant improvement of electrode interface stability through the unique electron acceptor properties, polar functional group effects, and highly dispersed composite structure of fullerene chloride. At the same time, combined with the high-activity material loaded electrode construction strategy, it further enhances the capacity retention, cycle life, and practical application feasibility of aqueous zinc-iodine batteries.

[0062] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any changes made based on the design principles of the present invention, or any non-creative modifications made thereon, shall fall within the scope of protection of the present invention.

Claims

1. A zinc iodide-fullerene chloride composite cathode material, characterized in that, include: Zinc iodide and fullerene chloride, wherein the fullerene chloride has the molecular formula: C 60 Cl6.

2. A method for preparing a zinc iodide battery positive electrode, characterized in that, include: Step 1: Add zinc iodide, fullerene chloride, and a conductive agent to a quartz mortar in a specific ratio and grind thoroughly to obtain a composite powder in the form of fine powder. Step 2: Add a dispersant to the composite powder and continuously stir to form a slurry with uniform component distribution. Then add a binder to the slurry and stir further. During stirring, the gradual volatilization of the dispersant promotes an increase in the solid content of the system, causing the mixture to gradually transform from a slurry state to a semi-dry agglomerate until no obvious solid adheres to the container sidewall. Step 3: Form the obtained semi-dry agglomerate into a film using a roll forming process, and then compact the film under pressure. Place the compacted film in a vacuum oven for vacuum drying to completely remove residual dispersant, ultimately obtaining a dry and dense self-supporting zinc iodide-fullerene chloride composite cathode film.

3. The method for preparing a zinc iodide battery positive electrode as described in claim 2, characterized in that: The total mass fraction of zinc iodide, fullerene chloride, conductive agent, and binder in the slurry is 50–90%.

4. The method for preparing a zinc iodide battery positive electrode as described in claim 2, characterized in that: The mass ratio of zinc iodide, fullerene chloride, conductive agent and binder is (10–85):(5–10):(5–40):(5–40).

5. The method for preparing a zinc iodide battery positive electrode as described in claim 2, characterized in that: The thickness of the self-supporting positive electrode film is 50-1000 μm.

6. The method for preparing a zinc iodide battery positive electrode as described in claim 2, characterized in that, The drying in step three is carried out in a vacuum oven at 45°C for 12-24 hours.

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