Chloride ion battery for realizing bromine / chlorine synergistic chemistry and preparation method thereof

Abstract

The invention discloses a chloride ion battery for realizing bromine / chlorine synergistic chemistry and a preparation method thereof, and belongs to the technical field of redox batteries. The chloride ion battery takes graphite paper coated with vanadium pentoxide and graphite as a positive electrode, wherein the mass ratio of the vanadium pentoxide to the graphite is (0.5: 1)-(2: 1); zinc foil is used as a negative electrode, and an electrolyte is a mixed aqueous solution of tetramethylammonium chloride and lithium bromide. A double-halogen system of a V2O5-graphite composite positive electrode is adopted, chlorine species are chemically stabilized through the action of bromine, BrCl is generated in the charging process to inhibit Cl2 formation, and meanwhile, the intercalation energy barrier of chlorine is reduced; according to the salt-in-water electrolyte based on tetramethylammonium chloride, an electrochemical window is expanded to 3.0 V, and BrCl hydrolysis is effectively inhibited. The high-voltage halogen ion battery prepared by the method can realize a 2.3 V discharge platform, provides a specific capacity of 600mAh g <-1 >, has a capacity retention rate of 90% after 200 cycles, and opens up a safe development path for the high-voltage halogen ion battery without toxic gas emission. In addition, the battery system is simple in structure and has remarkable cost benefits.

Description

Technical Field

[0001] The present invention belongs to the field of batteries, and relates to a chloride ion battery realizing bromine / chlorine synergistic chemistry and a preparation method thereof, and is a novel low-cost, high-capacity chloride ion battery and a preparation method thereof. Background Art

[0002] Recent technological breakthroughs have made lithium-ion intercalation systems an important solution for energy storage applications, and have made significant progress. Although traditional lithium-ion batteries still maintain their dominant position in various industries, the frequent safety accidents related to them in recent years have prompted the industry to deeply reflect on their operational reliability. The classic intercalation battery system (represented by lithium-ion batteries) has the characteristics of a high discharge platform, but its capacity is limited by the intrinsic properties of the material; while the redox battery configuration (represented by chloride ion batteries) exhibits completely opposite electrochemical performance characteristics. Despite operating at a lower voltage, conversion battery systems generally exhibit better energy density than intercalation systems. For cost-effective applications, redox chemical mechanisms may provide a viable technical solution. Given that chlorine, bromine and iodine have 755, 335 and 211 mAh g, respectively -1 The calculated value of theoretical specific capacity shows that salt water batteries have significant advantages in both economy and specific capacity characteristics.

[0003] However, due to the high vapor pressure of Cl2 and Br2 in aqueous electrolytes, these active substances are prone to volatilization during the redox process, which not only leads to battery capacity decay and shortened cycle life, but also raises major concerns about its safety. Therefore, conductive halogen host materials are the key to realizing reversible solid-state halogen ion battery electrochemical systems, because the inherent electron transport limitations of active halides must rely on external conductive pathways to achieve efficient redox processes. Graphite is widely used as an ideal electrode material for electrochemical energy storage systems due to its structural adjustability, surface configuration designability and excellent conductivity. However, under room temperature conditions, a single Cl 0 Embedment into the graphite lattice is still thermodynamically restricted unless accompanied by Br 0 Co-intercalation or introduction of catalytic mediators into the electrode structure.

[0004] Since their introduction, chloride-ion batteries have struggled to find suitable cathode materials. Plagued by issues like easy dissolution and poor reversibility, they have resulted in short cycle lives. Chloride-ion batteries have also been plagued by chlorine gas emissions, which not only impact battery performance but also pose serious toxicity and safety concerns. Consequently, chloride-ion batteries are still in their infancy, plagued by low current density and voltage. Summary of the Invention

[0005] In response to the above problems, the present invention proposes a novel chlorine fixation method, and realizes the innovative application of this method in zinc-chloride battery systems by strategically introducing low-potential bromine species into the electrochemical system dominated by high-potential chlorine. The present invention utilizes the synergistic effect between halogens to not only improve the thermodynamic reversibility of the chlorine redox reaction, but also activates the 1.0-1.3V low-voltage platform that was originally dormant in the zinc-chloride battery through electrochemical activation, thereby significantly improving the battery capacity and energy conversion efficiency by optimizing the halogen utilization. The vanadium pentoxide-graphite composite positive electrode realizes the gradient intercalation of electrochemically generated bromine and chlorine species through synergistic halogen redox chemistry to form a stable graphite intercalation compound. This new salt-in-water battery system based on tetramethylammonium chloride not only significantly expands the electrochemical stability window of aqueous batteries to 3.0V, but also effectively regulates the zinc negative electrode interface dynamics through the double-layer reconstruction mechanism, thereby inhibiting dendrite growth while improving the surface reaction activity. The dihalogen redox couple (Br 0 / Br - and Cl 0 / Cl - ) to achieve three characteristic discharge platforms of 2.3-1.9V, 1.9-1.7V and 1.7-1.6V, and obtain 600mAh g -1 The battery system uses only commercially available raw materials and does not require an ion exchange membrane, demonstrating excellent cost-effectiveness through a simplified manufacturing process.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A chloride ion battery that achieves bromine / chlorine synergistic chemistry. This chloride ion battery utilizes a dual-halogen system with a V2O5-graphite composite positive electrode. Bromine chemically stabilizes chlorine species, generating BrCl during charging to inhibit Cl2 formation and simultaneously lower the chlorine insertion barrier. Specifically, the chloride ion battery utilizes graphite paper coated with vanadium pentoxide and graphite as the positive electrode, with the mass ratio of vanadium pentoxide to graphite being 0.5:1-2:1. It also utilizes zinc foil as the negative electrode, and the electrolyte is a mixed aqueous solution of tetramethylammonium chloride and lithium bromide.

[0008] Furthermore, in the mixed aqueous solution, the concentration of tetramethylammonium chloride is 5 mol / L, and the concentration of lithium bromide is 1-2 mol / L.

[0009] Furthermore, the mass ratio of the positive electrode, vanadium pentoxide and graphite is preferably 1:1.

[0010] Furthermore, the mixed aqueous solution preferably contains 5 mol / L tetramethylammonium chloride and 2 mol / L lithium bromide.

[0011] A method for preparing a chloride ion battery based on a water-in-salt electrolyte, comprising the following steps:

[0012] Step (1): Grind the zinc sheet with sandpaper to remove surface oxides, then wash the graphite paper and zinc sheet with ethanol and distilled water respectively, and then vacuum dry them.

[0013] In step (2), tetramethylammonium chloride is first added into a stirred reactor, and then deionized water is continuously added and stirred to obtain a tetramethylammonium chloride solution with a concentration of 5 mol / L.

[0014] Step (3), adding lithium bromide to the tetramethylammonium chloride solution in step (2) to obtain an electrolyte.

[0015] Step (4) prepares a positive electrode material slurry, weighs vanadium pentoxide and graphite in proportion, then grinds them thoroughly in an agate mortar, adds an appropriate amount of N-methylpyrrolidone to make it a flowing slurry, and then evenly coats it on graphite paper and vacuum-dries it at 50-70°C for 2-3 hours to obtain the required positive electrode sheet.

[0016] Step (5), using the positive electrode sheet in step (4) as the positive electrode and the zinc sheet as the negative electrode to assemble into a soft pack battery.

[0017] Step (6) is to perform charge and discharge cycles on the battery to activate it and achieve optimal performance.

[0018] Furthermore, in the step (4), every 1 cm 2 0.1~0.2ml of the homogenate was applied on the graphite paper.

[0019] Furthermore, in step (6), the current density used in the activation process is 0.6A g -1 The activation charge and discharge cycles are approximately 5 cycles.

[0020] The reaction mechanism of the present invention is as follows:

[0021] In the tetramethylammonium chloride salt-water electrolyte system, graphite paper is used as the positive electrode and zinc sheet is used as the negative electrode. During the battery activation stage, Zn is generated on the negative electrode surface. 2+ layer, providing a reaction interface for the negative electrode chemical reaction, thereby changing the charge and discharge mechanism of the zinc negative electrode. During the battery charging process, Br - First oxidized to Br 0 and inserted into the graphite layer, then Cl -Under the catalytic action of vanadium pentoxide, it is oxidized and combines with Br0 to form BrCl, which is then inserted into the graphite layer. The presence of a high concentration of tetramethylammonium chloride in the electrolyte prevents the hydrolysis of BrCl. Therefore, no free Cl2 is generated during the entire reaction, achieving chlorine fixation and solving the toxicity problem of chloride ion batteries. The battery reaction equation is as follows:

[0022] Positive electrode: BrCl + Br2 + 4e - ↔ 3Br - + Cl -

[0023] Anode: 2Zn – 4e - ↔ 2Zn 2+

[0024] Overall reaction equation: BrCl + Br2 + 2Zn ↔ 2Zn 2+ + 3Br - + Cl -

[0025] Compared with the prior art, the present invention has the following significant advantages and beneficial effects:

[0026] (1) The innovative technology provided by the present invention utilizes the Br- / Br0-Cl- / Cl0 dihalogen redox pair to construct a synergistic halogen chemical mechanism: the charge transfer kinetics of lithium bromide improves the intercalation efficiency of chlorine, while the high redox potential of lithium bromide stabilizes the reversibility of chlorine redox from a thermodynamic perspective, achieving a capacity retention rate of 90% after 200 cycles through a self-regulating halogen compensation mechanism.

[0027] (2) The strategic integration of the novel, economical and efficient tetramethylammonium chloride-based salt-in-water electrolyte and vanadium pentoxide-graphite composite electrode provided by the present invention synergistically improves the specific capacity and discharge platform voltage. The innovative analysis is as follows: the high concentration of chloride ions in the salt-in-water electrolyte promotes the formation of BrCl, while the abundant quaternary ammonium ions not only inhibit the hydrolysis of BrCl, but also regulate the formation of polyhalogen polymers, effectively binding the halogen molecules inside the cathode, thereby completely blocking their escape path. Under 1C constant current discharge conditions, the optimized battery system exhibits a discharge platform voltage of 2.3V and a maximum areal capacity of 600 mAh / g. The static chloride ion battery architecture using this technology shows strong commercial potential due to its balanced electrochemical performance and economic feasibility, providing an innovative solution for large-scale energy storage applications. Through carefully designed redox coupling and charge transfer optimization, the intentional introduction of halogen synergistic mechanisms has opened up unprecedented research opportunities for advancing halogen battery technology.

[0028] (3) In addition, the bromine-mediated regulation of the generation of zero-valent chlorine species combined with chemical fixation technology has constructed a general method system applicable to various chemical fields, providing practical solutions for catalytic systems, environmental remediation technologies and industrial halogenation processes, and effectively addressing key challenges in large-scale chemical manufacturing. This chlorine fixation strategy also provides innovative solutions for diversified applications in the chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a charge and discharge curve diagram of Example 1.

[0030] Figure 2 2 are charge and discharge curves of Comparative Examples 1 and 4.

[0031] Figure 3 is the capacity retention rate of the battery of Examples 1-5.

[0032] Figure 4 This is the XRD test diagram of the positive electrode during the charging and discharging process of the battery in Example 1. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the embodiments of the present invention are further described below with reference to examples.

[0034] Example 1

[0035] Electrode preparation: The zinc sheet was sanded to remove surface oxides, and then the graphite paper and zinc sheet were washed with ethanol and distilled water for 5 minutes respectively and dried in vacuum for 30 minutes. The graphite paper and zinc sheet were cut into 2.5*2.5cm 2 The size of the sheet is used as the current collector of the battery. Then, the corresponding mass of positive electrode material is weighed according to the ratio of vanadium pentoxide to graphite of 1:1, and then it is put into the agate mortar and ground thoroughly. Then, an appropriate amount of N-methylpyrrolidone is added to make it into a flowing slurry, and then it is evenly coated on the graphite paper, every 1cm 2 0.1 ml of the slurry was coated on graphite paper and dried at 50°C for 2 hours to obtain the required positive electrode sheet.

[0036] Prepare the electrolyte: First, place 5.48g of tetramethylammonium chloride in a test tube. Add deionized water until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is Solution A. Then, place 1.736g of anhydrous lithium bromide in a test tube. Add Solution A until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is the electrolyte. The concentration of tetramethylammonium chloride is 5mol / L, and the concentration of lithium bromide is 2mol / L. Assemble the soft-pack battery.

[0037] The battery was charged and discharged for activation, where the current density used in the activation process was 0.6 A g -1 The activation charge and discharge cycles were 5 cycles.

[0038] Example 2

[0039] Electrode preparation: The zinc sheet was sanded to remove surface oxides, and then the graphite paper and zinc sheet were washed with ethanol and distilled water for 5 minutes respectively and dried in vacuum for 30 minutes. The graphite paper and zinc sheet were cut into 2.5*2.5cm 2 The size of the sheet is used as the current collector of the battery. Then, the corresponding mass of positive electrode material is weighed according to the ratio of vanadium pentoxide: graphite of 0.5:1, and then it is put into the agate mortar and ground thoroughly. Then, an appropriate amount of N-methylpyrrolidone is added to make it into a flowing slurry, and then it is evenly coated on the graphite paper, every 1cm 2 0.1 ml of the slurry was coated on graphite paper and dried at 60° C. for 2.5 hours to obtain the required positive electrode sheet.

[0040] Prepare the electrolyte: First, place 5.48g of tetramethylammonium chloride in a test tube. Add deionized water until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is Solution A. Then, place 1.736g of anhydrous lithium bromide in a test tube. Add Solution A until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is the electrolyte. The concentration of tetramethylammonium chloride is 5mol / L, and the concentration of lithium bromide is 2mol / L. Assemble the soft-pack battery.

[0041] The battery was charged and discharged for activation, where the current density used in the activation process was 0.6 A g -1 The activation charge and discharge cycles were 5 cycles.

[0042] Example 3

[0043] Electrode preparation: The zinc sheet was sanded to remove surface oxides, and then the graphite paper and zinc sheet were washed with ethanol and distilled water for 5 minutes respectively and dried in vacuum for 30 minutes. The graphite paper and zinc sheet were cut into 2.5*2.5cm 2 The size of the sheet is used as the current collector of the battery. Then, the corresponding mass of positive electrode material is weighed according to the ratio of vanadium pentoxide to graphite of 2:1, and then it is put into the agate mortar and ground thoroughly. Then, an appropriate amount of N-methylpyrrolidone is added to make it into a flowing slurry, and then it is evenly coated on the graphite paper, every 1cm 2 0.2 ml of the slurry was coated on graphite paper and dried at 60° C. for 3 hours to obtain the required positive electrode sheet.

[0044] Prepare the electrolyte: First, place 5.48g of tetramethylammonium chloride in a test tube. Add deionized water until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is Solution A. Then, place 1.736g of anhydrous lithium bromide in a test tube. Add Solution A until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is the electrolyte. The concentration of tetramethylammonium chloride is 5mol / L, and the concentration of lithium bromide is 2mol / L. Assemble the soft-pack battery.

[0045] The battery was charged and discharged for activation, where the current density used in the activation process was 0.6 A g -1 The activation charge and discharge cycles were 5 cycles.

[0046] Example 4

[0047] Electrode preparation: The zinc sheet was sanded to remove surface oxides, and then the graphite paper and zinc sheet were washed with ethanol and distilled water for 5 minutes respectively and dried in vacuum for 30 minutes. The graphite paper and zinc sheet were cut into 2.5*2.5cm 2 The size of the sheet is used as the current collector of the battery. Then, the corresponding mass of positive electrode material is weighed according to the ratio of vanadium pentoxide: graphite of 0.5:1, and then it is put into the agate mortar and ground thoroughly. Then, an appropriate amount of N-methylpyrrolidone is added to make it into a flowing slurry, and then it is evenly coated on the graphite paper, every 1cm 2 0.2 ml of the slurry was coated on graphite paper and dried at 70° C. for 3 hours to obtain the required positive electrode sheet.

[0048] Prepare the electrolyte: First, place 5.48g of tetramethylammonium chloride in a test tube. Add deionized water until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is Solution A. Then, place 0.868g of anhydrous lithium bromide in a test tube. Add Solution A until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is the electrolyte. The concentration of tetramethylammonium chloride is 5mol / L, and the concentration of lithium bromide is 1mol / L. Assemble the soft-pack battery.

[0049] The battery was charged and discharged for activation, where the current density used in the activation process was 0.6 A g -1 The activation charge and discharge cycles were 5 cycles.

[0050] Example 5

[0051] Electrode preparation: The zinc sheet was sanded to remove surface oxides, and then the graphite paper and zinc sheet were washed with ethanol and distilled water for 5 minutes respectively and dried in vacuum for 30 minutes. The graphite paper and zinc sheet were cut into 2.5*2.5cm 2The size of the sheet is used as the current collector of the battery. Then, the corresponding mass of positive electrode material is weighed according to the ratio of vanadium pentoxide: graphite of 0.5:1, and then it is put into the agate mortar and ground thoroughly. Then, an appropriate amount of N-methylpyrrolidone is added to make it into a flowing slurry, and then it is evenly coated on the graphite paper, every 1cm 2 0.2 ml of the slurry was coated on graphite paper and dried at 60° C. for 3 hours to obtain the required positive electrode sheet.

[0052] Prepare the electrolyte: First, place 5.48g of tetramethylammonium chloride in a test tube. Add deionized water until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is Solution A. Then, place 1.30g of anhydrous lithium bromide in a test tube. Add Solution A until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is the electrolyte. The concentration of tetramethylammonium chloride is 5mol / L, and the concentration of lithium bromide is 2mol / L. Assemble the soft-pack battery.

[0053] The battery was charged and discharged for activation, where the current density used in the activation process was 0.6 A g -1 The activation charge and discharge cycles were 5 cycles.

[0054] Comparative Example 1

[0055] Electrode preparation: The zinc sheet was sanded to remove surface oxides, and then the graphite paper and zinc sheet were washed with ethanol and distilled water for 5 minutes respectively and dried in vacuum for 30 minutes. The graphite paper and zinc sheet were cut into 2.5*2.5cm 2 Then, only vanadium pentoxide was put into an agate mortar and ground thoroughly, and then an appropriate amount of N-methylpyrrolidone was added to make it into a flowing slurry, and then it was evenly coated on the graphite paper, every 1 cm 2 0.2 ml of the slurry was coated on graphite paper and dried at 60° C. for 3 hours to obtain the required positive electrode sheet.

[0056] Prepare the electrolyte: First, place 5.48g of tetramethylammonium chloride in a test tube. Add deionized water until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is Solution A. Then, place 1.736g of anhydrous lithium bromide in a test tube. Add Solution A until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is the electrolyte. The concentration of tetramethylammonium chloride is 5mol / L, and the concentration of lithium bromide is 2mol / L. Assemble the soft-pack battery.

[0057] The battery was charged and discharged for activation, where the current density used in the activation process was 0.6 A g -1The activation charge and discharge cycles were 5 cycles.

[0058] Comparative Example 2

[0059] Electrode preparation: The zinc sheet was sanded to remove surface oxides, and then the graphite paper and zinc sheet were washed with ethanol and distilled water for 5 minutes respectively and dried in vacuum for 30 minutes. The graphite paper and zinc sheet were cut into 2.5*2.5cm 2 The size of the sheet is used as the current collector of the battery. Then, the graphite powder is put into the agate mortar and ground thoroughly. Then, an appropriate amount of N-methylpyrrolidone is added to make it into a flowing slurry. 2 0.2 ml of the slurry was coated on the graphite paper, and then evenly coated on the graphite paper and dried at 60° C. for 3 hours to obtain the required positive electrode sheet.

[0060] Prepare the electrolyte: First, place 5.48g of tetramethylammonium chloride in a test tube. Add deionized water until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is Solution A. Then, place 1.736g of anhydrous lithium bromide in a test tube. Add Solution A until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is the electrolyte. The concentration of tetramethylammonium chloride is 5mol / L, and the concentration of lithium bromide is 2mol / L. Assemble the soft-pack battery.

[0061] The battery was charged and discharged for activation, where the current density used in the activation process was 0.6 A g -1 The activation charge and discharge cycles were 5 cycles.

[0062] Comparative Example 3

[0063] Electrode preparation: The zinc sheet was sanded to remove surface oxides, and then the graphite paper and zinc sheet were washed with ethanol and distilled water for 5 minutes respectively and dried in vacuum for 30 minutes. The graphite paper and zinc sheet were cut into 2.5*2.5cm 2 The thin sheets of different sizes are used as the current collector of the battery. Graphite paper is used as the positive electrode.

[0064] Prepare the electrolyte: First, place 5.48g of tetramethylammonium chloride in a test tube. Add deionized water until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is Solution A. Then, place 1.736g of anhydrous lithium bromide in a test tube. Add Solution A until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is the electrolyte. The concentration of tetramethylammonium chloride is 5mol / L, and the concentration of lithium bromide is 2mol / L. Assemble the soft-pack battery.

[0065] The battery was charged and discharged for activation, where the current density used in the activation process was 0.6 A g-1 The activation charge and discharge cycles were 5 cycles.

[0066] Comparative Example 4

[0067] Electrode preparation: The zinc sheet was sanded to remove surface oxides, and then the graphite paper and zinc sheet were washed with ethanol and distilled water for 5 minutes respectively and dried in vacuum for 30 minutes. The graphite paper and zinc sheet were cut into 2.5*2.5cm 2 The size of the sheet is used as the current collector of the battery. Then, the corresponding mass of positive electrode material is weighed according to the ratio of vanadium pentoxide to graphite of 1:1, and then it is put into the agate mortar and ground thoroughly. Then, an appropriate amount of N-methylpyrrolidone is added to make it into a flowing slurry, and then it is evenly coated on the graphite paper, every 1cm 2 0.2 ml of the slurry was coated on graphite paper and dried at 60° C. for 3 hours to obtain the required positive electrode sheet.

[0068] Prepare the electrolyte: First, place 5.48g of tetramethylammonium chloride in a test tube. Add deionized water until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is Solution A. Then, place 0.848g of anhydrous lithium chloride in a test tube. Add Solution A until the total liquid volume is 10ml. Shake well until the solid powder is completely dissolved. This is the electrolyte. The concentration of tetramethylammonium chloride is 5mol / L, and the concentration of lithium chloride is 2mol / L. Assemble the soft-pack battery.

[0069] The battery was charged and discharged for activation, where the current density used in the activation process was 0.6 A g -1 The activation charge and discharge cycles were 5 cycles.

[0070] The charge cut-off voltage of Examples 1-5 and Comparative Examples 1-4 was 2.5 V, the charge time was 1 hour, the discharge cut-off voltage was 0.5 V, and the number of charge and discharge cycles was 200. Table 1 shows the coulombic efficiency, voltage efficiency, and energy efficiency of Examples 1-5 and Comparative Examples 1-4. Figure 2 The discharge curves of the battery composed of Example 1 and the batteries composed of Comparative Examples 1-4 are compared. Figure 3 It represents the capacity retention rate of the battery composed of Examples 1-5, Figure 4 It shows the capacity retention rate of the batteries composed of Comparative Examples 1-4.

[0071] Table 1 Battery performance of examples and comparative examples

[0072]

[0073] It can be seen from Table 1 that the battery performance of Examples 1-5 is significantly higher than that of Comparative Examples 1-4.

[0074] Depend on Figure 1 and Figure 2 It can be seen from the comparison that the discharge platform, discharge capacity and efficiency of Example 1 are significantly better than those of Comparative Example 1 and Comparative Example 4. Figure 3 Cycling performance analysis shows that the battery systems constructed in Examples 1-5 exhibit excellent capacity retention, maintaining >95% of their initial capacity after 200 deep cycles, with a capacity decay rate of less than 0.012% / cycle. This significant difference is attributed to the following synergistic mechanisms:

[0075] (1) Redox activity regulation: The introduction of bromide ions generates an intermediate halogen compound BrCl through the interaction between halogens, which reduces the electrochemical barrier of chloride intercalation.

[0076] (2) Catalytic effect of positive electrode active material: vanadium pentoxide in the positive electrode acts as a catalyst to catalyze the formation of halogen compounds during the charge and discharge process; graphite in the positive electrode acts as a host of halogen to prevent the escape of gaseous halogen molecules. The role of positive electrode active material can be seen from Figure 4 see.

[0077] In summary, we have successfully constructed a high-performance static zinc halide battery system by strategically introducing bromine into the zinc-chloride electrochemical system. - / Br 0 -Cl - / Cl 0 The dual redox couple establishes a synergistic halogen chemical mechanism - the bromine-mediated charge transfer kinetics improves the intercalation efficiency of chlorine. At the same time, the high redox potential of bromine stabilizes the redox reversibility of chlorine from a thermodynamic point of view, and achieves a capacity retention rate of 90% after 200 cycles through a self-regulating halogen compensation mechanism. By strategically integrating a new low-cost tetramethylammonium chloride-based aqueous electrolyte with a vanadium pentoxide-graphite composite electrode, the specific capacity and discharge platform voltage are synergistically improved. The high chloride ion concentration of the electrolyte promotes the formation of BrCl, while the abundant quaternary ammonium ions not only inhibit the hydrolysis of BrCl, but also mediate the formation of polyhalogen polymers to confine the halogen molecules in the positive electrode, effectively preventing them from escaping. Under 1C constant current discharge conditions, the battery system exhibited a discharge platform of 2.3V and a capacity of 600 mAh g -1 The static zinc-halide battery architecture using this electrolyte technology demonstrates strong commercial potential with its balanced electrochemical performance and economic feasibility, providing an innovative solution for large-scale energy storage applications.

[0078] The above-described embodiments merely express the implementation methods of the present invention, but should not be understood as limiting the scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A chloride ion battery that realizes bromine / chlorine cooperative chemistry, characterized in that: The chloride ion battery is a chloride ion battery based on a salt-in-water electrolyte, which uses graphite paper coated with vanadium pentoxide and graphite as the positive electrode, wherein the mass ratio of vanadium pentoxide to graphite is 0.5:1-2:1; uses zinc foil as the negative electrode, and the electrolyte is a mixed aqueous solution of tetramethylammonium chloride and lithium bromide.

2. A chloride ion battery realizing bromine / chlorine synergistic chemistry according to claim 1, characterized in that: In the mixed aqueous solution, the concentration of tetramethylammonium chloride is 5 mol / L, and the concentration of lithium bromide is 1-2 mol / L.

3. A chloride ion battery realizing bromine / chlorine synergistic chemistry according to claim 1, characterized in that: In the mixed aqueous solution, the concentration of tetramethylammonium chloride is 5 mol / L, and the concentration of lithium bromide is 2 mol / L.

4. A chloride ion battery realizing bromine / chlorine synergistic chemistry according to claim 1, characterized in that: In the positive electrode, the mass ratio of vanadium pentoxide to graphite is preferably 1:

1.

5. A method for preparing a chloride ion battery realizing bromine / chlorine synergistic chemistry according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step (1), grinding the zinc sheet, washing the graphite paper and the zinc sheet, and then vacuum drying; Step (2), adding tetramethylammonium chloride into a stirred reactor, and then continuously adding deionized water and stirring to obtain a tetramethylammonium chloride solution; Step (3), adding lithium bromide to the tetramethylammonium chloride solution in step (2) to obtain an electrolyte; Step (4) prepares a positive electrode material slurry, weighs vanadium pentoxide and graphite in proportion, grinds them thoroughly, adds N-methylpyrrolidone to make them into a flowing slurry, evenly coats them on graphite paper, and vacuum-dries them to obtain a positive electrode sheet; Step (5), using the positive electrode sheet in step (4) as the positive electrode and the zinc sheet as the negative electrode to assemble into a soft pack battery; Step (6) is to perform charge and discharge cycles on the battery to activate it and achieve optimal performance.

6. The method for preparing a chloride ion battery realizing bromine / chlorine synergistic chemistry according to claim 5, characterized in that: In the step (4), every 1 cm 2 0.1~0.2ml of the homogenate was applied on the graphite paper.

7. The method for preparing a chloride ion battery realizing bromine / chlorine synergistic chemistry according to claim 5, characterized in that: In the step (6), the current density used in the activation process is 0.6A g -1 ; The number of activation charge and discharge cycles is about 5 cycles.

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