Aqueous zinc-bromine battery

Abstract

The application provides a water-based zinc-bromine battery, and belongs to the field of energy storage batteries.The water-based zinc-bromine battery comprises a positive electrode, a negative electrode and a water-based electrolyte, wherein the positive electrode comprises a first substrate and a solid-phase bromide active substance coated on the first substrate; the negative electrode comprises a second substrate, a metal / metal zinc heterojunction interface layer and metal zinc electrodeposited on the metal / metal zinc heterojunction interface layer; the water-based electrolyte comprises a mixed aqueous solution of a zinc salt, a bromine salt, a pH regulator and a zinc negative electrode stabilizer; wherein a complexing agent is reacted with bromine to obtain the solid-phase bromide active substance, and the solid-phase bromide active substance is mixed with a conductive agent, a binder and a solvent and then coated on the first substrate.

Description

Technical Field

[0001] This invention belongs to the field of energy storage batteries, and particularly relates to an aqueous zinc-bromine battery. Background Technology

[0002] Renewable energy sources such as wind and solar power play a crucial role in future smart grids, effectively mitigating pollution from traditional fossil fuels and their own energy scarcity. However, renewable energy is subject to environmental limitations, exhibiting intermittency and randomness, necessitating energy storage devices for frequency regulation and energy storage. Rechargeable batteries, as energy storage devices, are attracting significant attention in large-scale energy storage due to their low cost, lack of geographical limitations, and short investment cycles.

[0003] Aqueous Zn-Br2 batteries are strong contenders for next-generation large-scale energy storage batteries due to their low cost, lack of pollution, high safety, and stability. However, traditional zinc-bromine flow batteries suffer from numerous problems that limit their large-scale application. For example, bromide ion diffusion leads to cross-contamination between the positive and negative electrodes, and the zinc negative electrode is susceptible to side reactions, resulting in poor stability. This reduces battery efficiency and cycle stability, and increases the maintenance costs of the flow circulation system, thus raising battery costs. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an aqueous zinc-bromine battery, aiming to at least partially solve these problems.

[0005] Specifically, the technical solution provided by this invention is as follows:

[0006] An aqueous zinc-bromine battery, comprising:

[0007] The positive electrode includes a first substrate and a solid-phase bromide active material coated on the first substrate;

[0008] The negative electrode comprises a second substrate, a metal / zinc alloy heterojunction interface layer, and zinc electrodeposited on the metal / zinc alloy heterojunction interface layer; and

[0009] The aqueous electrolyte is a mixed aqueous solution including zinc salt, bromide salt, pH adjuster and zinc negative electrode stabilizer;

[0010] In this process, a complexing agent reacts with bromine to obtain a solid-phase bromide active material. The solid-phase bromide active material is then mixed with a conductive agent, a binder, and a solvent, and then coated onto a first substrate.

[0011] Based on the above technical solution, the aqueous Zn-Br2 battery provided by the present invention has at least one of the following beneficial effects:

[0012] (1) According to an embodiment of the present invention, the positive electrode of the Zn-Br2 battery of the present invention is formed by reacting a complexing agent with bromine to generate a solid-phase bromide active material, which is then mixed with a conductive agent, a binder, and a solvent and coated onto a first substrate. For the positive electrode, by using a conductive agent, a binder, etc. to coat the solid-phase bromide active material onto the first substrate, during the solid / liquid phase conversion reaction, the solid-phase bromide active material on the positive electrode will not diffuse or undergo side reactions during the reaction, effectively avoiding the problem of cross-contamination and corrosion of the positive and negative electrodes caused by Br- diffusion. At the same time, the solid-phase bromide active material coated on the positive electrode can be completely converted into discharge products Br- and ammonium salt cations during battery discharge. During charging, Br- in the electrolyte can complex with the zinc negative electrode stabilizer in the electrolyte to form a solid-phase bromide active material that is deposited on the positive electrode, thereby improving the reversibility of the battery. Furthermore, by introducing a conductive agent into the positive electrode, even if a large amount of solid bromide active material is coated on the first substrate, the positive electrode can still maintain good conductivity, and this method of coating solid bromide active material helps the positive electrode to obtain a high specific capacity.

[0013] (2) According to an embodiment of the present invention, for the negative electrode, by forming a metal / zinc alloy heterojunction interface layer on the substrate, the metal / zinc alloy heterojunction interface layer has a strong adsorption energy for zinc atoms and its own strong conductivity, enabling the heterojunction interface layer to regulate the uniform deposition electric field, thereby reducing the subsequent zinc ion nucleation energy barrier, and inducing zinc atoms to uniformly nucleate on the heterojunction interface layer, forming a uniform zinc coating. This improves the reversibility of the zinc negative electrode reaction and achieves stable zinc deposition and dissolution at a high areal capacity. In addition, the heterojunction interface layer can optimize the N / P ratio, which helps to improve the battery energy density and the application of the battery industry.

[0014] (3) According to the embodiments of the present invention, adding a zinc anode stabilizer to the electrolyte can effectively prevent some side reactions of the zinc anode, such as hydrogen evolution reaction, corrosion, passivation, electrode deformation and dendrite growth. The main reason is that the ammonia-containing positive ion groups in the zinc anode stabilizer can be adsorbed on the surface of the zinc anode, which can provide strong protection for the zinc anode. Moreover, this protection is continuous, thereby achieving the effect of protecting the zinc anode during the battery's large capacity and long-term operation.

[0015] (4) According to an embodiment of the present invention, by designing the structure of the positive and negative electrodes and the composition of the electrolyte in the aqueous Zn-Br2 battery, the advantages of the positive and negative electrodes and the electrolyte are coupled, which can significantly improve the electrical performance and stability of the aqueous Zn-Br2 battery. Attached Figure Description

[0016] Figure 1This is a schematic diagram of the reaction mechanism of the aqueous zinc-bromine battery in Example 1 of the present invention;

[0017] Figure 2 This is a charge-discharge curve of the aqueous Zn-Br2 battery in Embodiment 1 of the present invention;

[0018] Figure 3 This is a cycle curve of the aqueous Zn-Br2 battery in Embodiment 1 of the present invention;

[0019] Figure 4 The above graphs show the hydrogen evolution overpotential curves of the aqueous Zn-Br2 battery in Comparative Example 1 and Example 1 of this invention.

[0020] Figure 5 The negative electrode Tafel curves of the aqueous Zn-Br2 batteries in Comparative Example 1 and Example 1 of this invention are shown.

[0021] Figure 6 This is a charge-discharge curve of the aqueous Zn-Br2 battery in Comparative Example 2 of the present invention;

[0022] Figure 7 This is a cycle stability test curve of the aqueous Zn-Br2 battery in Comparative Example 2 of the present invention;

[0023] Figure 8 This is a charge-discharge curve of the aqueous Zn-Br2 battery in Comparative Example 3 of the present invention;

[0024] Figure 9 The graph shows the cycle stability test curve of the aqueous Zn-Br2 battery in Comparative Example 3 of this invention.

[0025] Figure 10 This is a charge-discharge curve of the aqueous Zn-Br2 battery in Comparative Example 4 of the present invention;

[0026] Figure 11 The graph shows the cycle stability test curve of the aqueous Zn-Br2 battery in Comparative Example 4 of this invention.

[0027] Figure 12 This is a charge-discharge curve of the acidic aqueous Zn-Br2 battery in Example 2 of the present invention;

[0028] Figure 13 The cycling curve of the soft-pack battery used in the scale-up experiment of the aqueous Zn-Br2 battery in Example 1 of this invention is shown. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0030] For traditional aqueous Zn-Br2 batteries, Br- The cross-contamination between the positive and negative electrodes caused by diffusion, as well as some side reactions present in the zinc negative electrode, limit the performance of aqueous Zn-Br2 batteries. This invention proposes a novel aqueous zinc-bromine battery by solidifying a bromide active material, coating it onto a first substrate as the positive electrode, introducing a metal / zinc alloy heterojunction interface layer in the negative electrode, and adding a zinc negative electrode stabilizer to the electrolyte. The Br in the electrolyte... - The zinc anode stabilizer in the electrolyte can complex with the positive electrode to generate new solid-phase bromide active material, which is deposited on the positive electrode, thereby increasing the areal capacity of the positive electrode. This solid / liquid phase conversion reaction avoids cross-contamination between the positive and negative electrodes. Introducing a metal / zinc alloy heterojunction interface layer on the negative electrode allows for the induction of zinc ion deposition and nucleation to form a zinc layer or the dissolution of the zinc layer, improving the reversibility and high areal capacity of the negative electrode. Furthermore, adding a zinc anode stabilizer to the electrolyte utilizes the ammonia-containing positive ion groups in the stabilizer, which can adsorb onto the negative electrode, providing protection and reducing side reactions. By implementing the aforementioned design for the positive and negative electrodes in the aqueous Zn-Br2 battery, it is beneficial to improve the battery's stable operation over a large areal capacity and for extended periods.

[0031] Specifically, according to an embodiment of the present invention, an aqueous zinc-bromine battery includes: a positive electrode, a negative electrode, and an aqueous electrolyte.

[0032] The positive electrode comprises a first substrate and a solid-phase bromide active material coated on the first substrate, wherein the positive electrode is used for the reaction of zero-valent bromine with Br. - The redox reaction, that is, during charging, Br - It is converted to zero-valent bromine; during discharge, zero-valent bromine is converted to Br. - .

[0033] Specifically, the formation of the positive electrode includes: after the complexing agent reacts with bromine to obtain a solid bromide active material, the solid bromide active material is mixed with a conductive agent, a binder, and a solvent, and then uniformly coated onto a first substrate.

[0034] More specifically, the preparation of the positive electrode includes: mixing 0.001-10 mol / L complexing agent with bromine for 5-300 min, centrifuging, and collecting the solid-phase bromide precursor. The obtained solid-phase bromide precursor is washed for 5-60 min, repeated 1-10 times, and collected after centrifugation. Then, it is dried in an oven at 40-160℃ for 2-24 h to obtain a dried solid-phase bromide active material. The obtained solid-phase bromide active material is mixed with a conductive agent, binder, and solvent in a specific ratio, and the resulting slurry is uniformly dropped onto a first substrate using a dropper. Then, it is dried in an oven at 40-160℃ for 4-40 h to obtain the positive electrode.

[0035] The negative electrode comprises a second substrate, a metal / zinc alloy heterojunction interface layer, and zinc electrodeposited on the metal / zinc alloy heterojunction interface layer, wherein the negative electrode is used for Zn… 2+ The redox reaction with Zn, i.e., during charging, Zn 2+ It is converted to Zn; during discharge, Zn is converted to Zn. 2+ .

[0036] Specifically, the formation of the negative electrode includes: immersing the second substrate in any electroplating solution containing Sb, Mn, Cr, Mg, or Fe salts, at an A / cm² pressure of 0.001–50 mA. 2 Constant current electroplating was performed at a current density of 0.5-100 mA / cm² for 1-120 min, followed by rinsing and preparation. Then, a second substrate deposited with any one of the metals selected from Sb, Mn, Cr, Mg, and Fe was placed in a zinc salt-containing electroplating solution and electroplated at a current density of 0.5-100 mA / cm². 2 Constant current electroplating is performed at a current density for 1-120 minutes to obtain the negative electrode. The zinc salt for pre-plating can be any one of ZnSO4, ZnCl2, Zn(CH3COO)2, Zn(NO3)2, Znl2, or Zn(CF3SO3)2.

[0037] The aqueous electrolyte is a mixed aqueous solution comprising zinc salt, bromide salt, pH adjuster and zinc negative electrode stabilizer.

[0038] According to an embodiment of the present invention, the first substrate and the second substrate are each independently selected from any one of carbon-based materials, metal current collectors, and non-metal current collectors. Preferably, the first substrate and the second substrate are materials with a high specific surface area, which can provide more sites for active substances, thereby promoting the reversibility of the positive electrode reaction and achieving a large areal capacity.

[0039] According to embodiments of the present invention, carbon-based materials include at least one of the following: graphite, graphene, carbon cloth, carbon paper, activated carbon, carbon microfibers, carbon nanofibers, carbon felt, graphite felt, carbon spheres, and carbon nanotubes.

[0040] According to embodiments of the present invention, the metal current collector includes at least one of silver, copper, titanium, gold, and platinum.

[0041] According to an embodiment of the present invention, the non-metallic current collector includes a glassy carbon electrode.

[0042] According to an embodiment of the present invention, the mass ratio of the solid bromide active material to the conductive agent, binder, and solvent is 0.01-20:0.01-3:0.1-1:100.

[0043] According to embodiments of the present invention, the complexing agent used in the preparation of the solid brominated active substance includes at least one of the following:

[0044] Tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetraethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide.

[0045] In embodiments of the present invention, the complexing agent is selected to be inexpensive, environmentally friendly, and capable of forming a solid-phase bromide active substance insoluble in the electrolyte with Br2. The main mechanism by which the complexing agent complexes with Br2 to form a solid-phase bromide active substance is that Br2 can react with the Br2 groups on the quaternary ammonium salt molecules. - Cl - I - Adsorption occurs and Br3 is formed. - Br2Cl - and Br2I - Group, at this time due to Br3 - Br2Cl - and Br2I - The groups have large radii and dispersed negative charges, making them easily polarized by quaternary ammonium salt cations (ammonia-containing positive ions), thus affecting Br3. - Br2Cl - and Br2I - The ionic bond between the functional group and the quaternary ammonium salt cation is transformed into a coordinate bond, forming a stable solid-phase bromide active substance.

[0046] According to embodiments of the present invention, the conductive agent includes at least one of the following:

[0047] Ketjen black, activated carbon, multi-walled carbon nanotubes, carbon nanospheres, amorphous carbon, and graphene.

[0048] According to embodiments of the present invention, the adhesive comprises at least one of the following:

[0049] Polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose (CMC), polytetrafluoroethylene (PTFE).

[0050] According to embodiments of the present invention, the solvent includes any one of water and 1-methyl-2-pyrrolidone (NMP).

[0051] According to embodiments of the present invention, the metal / zinc alloy heterojunction interface layer includes at least one of the following:

[0052] Mn / Mn-Zn alloy, Sb / Sb-Zn alloy, Mg / Mg-Zn alloy, Fe / Fe-Zn alloy, Cu / Cu-Zn alloy, Cr / Cr-Zn alloy, Ag / Ag-Zn alloy, Au / Au-Zn alloy.

[0053] In embodiments of the present invention, metals with strong solubility for zinc are preferentially selected to form the metal / zinc alloy heterojunction interface layer. The formed heterojunction interface layer also has strong adsorption energy and strong conductivity for zinc, and has the function of regulating a uniform deposition electric field. Therefore, the zinc deposited subsequently can be uniformly nucleated on the heterojunction interface layer and form a uniform zinc plating layer as an active material.

[0054] According to embodiments of the present invention, the zinc anode stabilizer comprises at least one of the following:

[0055] Tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetramethylammonium iodide, tetraethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide.

[0056] In embodiments of the present invention, the addition of a zinc anode stabilizer to the electrolyte effectively suppresses side reactions such as hydrogen evolution reaction, corrosion, passivation, electrode deformation, and dendrite growth at the anode. This is primarily because the ammonia-containing positive ion groups in the zinc anode stabilizer adsorb onto the anode surface, forming an electrostatic shielding effect. This strong interfacial interaction increases the overpotential of the hydrogen evolution reaction, regulates the uniformity of the current density on the anode surface, and increases the anode potential, thereby effectively suppressing hydrogen evolution reaction, corrosion, passivation, and dendrite growth at the anode. Simultaneously, the zinc anode stabilizer can complex with Br- in the electrolyte to form a solid-phase bromide active material that deposits on the cathode, thereby increasing the areal capacity of the cathode.

[0057] According to embodiments of the present invention, the zinc salt comprises at least one of the following:

[0058] ZnSO4, ZnCl2, Zn(NO3)2, ZnBr2, ZnI2, Zn(CH3COO)2 and Zn(CF3SO3)2;

[0059] Bromine salts include at least one of the following:

[0060] ZnBr2, KBr, NaBr, MnBr2, BaBr2, CuBr2, MgBr2C4H 12 BrN, C8H 10 BrN, C 12 H 28 BrN and C 16 H 36 BrN.

[0061] According to embodiments of the present invention, the zinc salt concentration is 0.01-30 mol / L, and can be selected from 0.01, 0.1, 1, 5, 10, 25, 30 mol / L, etc.; the bromide salt concentration is 0.01-30 mol / L, and can be selected from 0.01, 0.1, 1, 5, 10, 25, 30 mol / L, etc.; the zinc negative electrode stabilizer concentration is 0.01-10 mol / L, and can be selected from 0.01, 0.1, 1, 5, 10 mol / L, etc.

[0062] According to embodiments of the present invention, the aqueous electrolyte is neutral or acidic, and the acidity or alkalinity of the electrolyte is adjusted by using a pH adjuster.

[0063] According to embodiments of the present invention, the pH adjuster includes at least one of the following:

[0064] H2SO4 solution, HCl solution, HNO3 solution, CH3COOH solution, H3PO4 solution, H2CO3 solution, H2SiO3 solution and HClO solution; wherein the concentration of the pH adjuster is 0.01-10 mol / L, and can be selected as 0.01, 0.1, 1, 5, 10 mol / L, etc.

[0065] According to embodiments of the present invention, the battery provided by the present invention can be made into any one of the following: button cell, cylindrical cell, pouch cell, prismatic cell, and flow cell. Button cell batteries are characterized by their small size and ease of handling, and are commonly used in laboratory settings; cylindrical cells are characterized by their high energy density and are commonly used in portable energy sources such as laptops and digital cameras; pouch and prismatic cells have relatively simple structures and can achieve high energy density, and are commonly used as power batteries or large-scale energy storage equipment; flow cells are characterized by their large capacity and are commonly used in large-scale energy storage devices.

[0066] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings. However, it should be noted that the embodiments provided by the present invention are only for illustrative purposes and do not limit the scope of protection of the present invention.

[0067] Example 1

[0068] The aqueous Zn-Br2 battery provided in this embodiment includes a positive electrode, a negative electrode, and a neutral aqueous electrolyte.

[0069] Positive electrode: A solid-phase bromide active material TPABr3 (tetrapropylammonium tribromide), conductive agent Ketjen black, binder PVDF, and solvent NMP are mixed in a mass ratio of 10:1:0.5:100. The mixture is then evenly dropped onto a carbon felt using a dropper and dried in an oven at 80°C for 12 hours. The preparation of the solid-phase bromide active material TPABr3 includes: mixing 5 mol / L TPABr solution with bromine and stirring for 30 minutes, followed by centrifugation to collect the TPABr3 precursor. The obtained TPABr3 precursor is washed with deionized water for 30 minutes, repeated 10 times, and then collected after centrifugation. The obtained material is then dried in an oven at 80°C for 6 hours to obtain the solid-phase bromide active material TPABr3.

[0070] Negative electrode: A copper sheet electroplated with antimony is used, wherein the antimony electroplating solution is 0.06 mol / L SbCl3 + 4 mol / L concentrated sulfuric acid (the ratio can be adjusted to (0.000001~0.08) mol / L SbCl3 + (4~16) mol / L H2SO4). First, the polished copper sheet is placed in the electroplating solution at 3 mA / cm. 2 After constant current electroplating for 10 minutes, rinse thoroughly and set aside. Then, pre-plating with zinc is carried out in 2 mol / L ZnBr2 at 20 mA / cm². 2 Electroplating was performed under constant current for 45 minutes to obtain Zn / Sb2Zn3 / Sb / Cu foil negative electrode.

[0071] The neutral aqueous electrolyte uses 0.5 mol / L ZnBr2 as the zinc and bromine source and 0.25 mol / L TPABr (tetrapropylammonium bromide) as the zinc anode stabilizer.

[0072] Figure 1 This is a schematic diagram of the reaction mechanism of the aqueous zinc-bromine battery in Example 1 of the present invention.

[0073] like Figure 1 As shown, the possible reaction equations for the positive and negative electrodes involved in an aqueous zinc-bromine battery, along with their standard electrode potentials, are as follows:

[0074] positive electrode:

[0075] negative electrode:

[0076] Overall reaction:

[0077] The above-mentioned aqueous electrolyte, positive electrode, and negative electrode were assembled into an aqueous Zn-Br2 battery, and charge-discharge and cycle performance tests were conducted. The test results are as follows: Figure 2 and Figure 3 As shown.

[0078] Figure 2 This is a charge-discharge curve of the aqueous Zn-Br2 battery in Embodiment 1 of the present invention; Figure 3 This is a cycle curve diagram of the aqueous Zn-Br2 battery in Embodiment 1 of the present invention, wherein... Figure 2 and Figure 3 The charging and discharging test conditions for the aqueous zinc-bromine battery are as follows: charging at 1.9V and 10mA / cm. 2 Discharge.

[0079] Depend on Figure 2 and Figure 3 It can be seen that the areal capacity of the aqueous Zn-Br2 battery in Example 1 can reach 15 mAh / cm². 2 The average discharge voltage reached 1.63V, and the battery coulombic efficiency reached 99.7%. Additionally, the aqueous Zn-Br2 battery in Example 1 achieved a discharge efficiency of 15mAh / cm³. 2 It can stably cycle for more than 1000 times under its surface capacity.

[0080] Comparative Example 1

[0081] The preparation method of the aqueous Zn-Br2 battery in Comparative Example 1 is the same as that in Example 1, except that the zinc anode stabilizer TPABr (tetrapropylammonium bromide) is not added to the electrolyte.

[0082] Figure 4 The graph shows the hydrogen evolution overpotential curves of the negative electrode of the aqueous Zn-Br2 battery in Comparative Example 1 and Example 1 of this invention.

[0083] like Figure 4 As shown, after adding 0.1 mol / L TPABr zinc anode stabilizer to 1 mol / L KBr electrolyte (Example 1), the Zn pre-deposited Sb / Sb2Zn3 heterojunction interface electrode exhibited a higher hydrogen evolution overpotential of -1.74 V vs. Ag / AgCl at a current of 10 mA, which was significantly lower than -1.68 V vs. Ag / AgCl in 1 mol / L KBr electrolyte without the addition of zinc anode stabilizer TPABr (Comparative Example 1). This demonstrates that the addition of zinc anode inhibitor can effectively suppress the occurrence of hydrogen evolution side reactions (Example 1).

[0084] Furthermore, this invention conducts a comparative study on the corrosion of the negative electrode.

[0085] Figure 5 The image shows the Tafel curves of the negative electrode of the aqueous Zn-Br2 battery in Comparative Example 1 and Example 1 of this invention.

[0086] like Figure 5As shown, after adding 0.1 mol / L TPABr zinc anode stabilizer (Example 1) to a 1 mol / L KBr electrolyte, the Zn pre-deposited Sb / Sb2Zn3 heterojunction interface electrode exhibited an extremely low corrosion current density of approximately 0.021 mA / cm². 2 The corrosion rate was significantly lower than that in the case of 1 mol / L KBr electrolyte without the addition of zinc anode stabilizer TPABr (Comparative Example 1), indicating that the corrosion of the anode in Example 1 was well controlled.

[0087] Comparative Example 2

[0088] The preparation of the aqueous Zn-Br2 battery in Comparative Example 2 was the same as that in Example 1, except that carbon felt was used as the positive electrode, no solid bromide active material TPABr3 was modified on the positive electrode, and no zinc negative electrode stabilizer TPABr was added to the aqueous electrolyte. That is, an aqueous Zn-Br2 battery was assembled using a carbon felt positive electrode, a negative electrode formed by zinc pre-deposited on Cu foil at the Sb / Sb2Zn3 heterojunction interface layer, and 0.5 mol / L ZnBr2 as the electrolyte.

[0089] The electrochemical performance of the aqueous Zn-Br2 battery in Comparative Example 2 was tested, and the specific test results are as follows: Figure 6 and Figure 7 As shown.

[0090] Figure 6 This is a charge-discharge curve of the aqueous Zn-Br2 battery in Comparative Example 2 of the present invention; Figure 7 This is a cycle stability test curve of the aqueous Zn-Br2 battery in Comparative Example 2 of the present invention; wherein Figure 6 and Figure 7 The charging and discharging test conditions for the aqueous zinc-bromine battery are as follows: charging at 1.9V and 10mA / cm. 2 Discharge.

[0091] like Figure 6-7 As shown, the aqueous Zn-Br2 battery in Comparative Example 2 can only cycle for less than 50 times and has a coulombic efficiency of less than 50%. This is mainly because the Br2 generated at the positive electrode diffuses to the negative electrode during charging and has a strong corrosive effect on the negative electrode, resulting in severe self-discharge of the battery, which leads to poor coulombic efficiency and cycle stability.

[0092] Comparative Example 3

[0093] The aqueous Zn-Br2 battery in Comparative Example 3 is the same as the battery in Example 1, except that the positive electrode is made of carbon felt and is not modified with solid bromide active material TPABr3. That is, a Zn-Br2 battery is assembled using a carbon felt positive electrode, a negative electrode formed by zinc pre-deposited on Cu foil at the Sb / Sb2Zn3 heterojunction interface layer, and an electrolyte composed of 0.5 mol / L ZnBr2 as zinc source and bromine source and 0.25 mol / L TPABr (tetrapropylammonium bromide) zinc negative electrode stabilizer.

[0094] The electrochemical performance of the aqueous Zn-Br2 battery in Comparative Example 3 was tested, and the specific test results are as follows: Figure 8 and Figure 9 As shown.

[0095] Figure 8 This is a charge-discharge curve of the aqueous Zn-Br2 battery in Comparative Example 3 of the present invention; Figure 9 This is a cycle stability test curve of the aqueous Zn-Br2 battery in Comparative Example 3 of the present invention; wherein... Figure 8 and Figure 9 The charging and discharging test conditions for the aqueous zinc-bromine battery are as follows: charging at 1.9V and 10mA / cm. 2 Discharge.

[0096] like Figure 8-9 As shown, the discharge voltage of the battery in Comparative Example 3 is about 1.46V, and it can only cycle stably for less than 120 cycles, indicating that the electrochemical performance of the battery in Comparative Example 3 is far lower than that of the aqueous Zn-Br2 battery in Example 1.

[0097] Furthermore, the present invention also tested the electrochemical performance of the aqueous Zn-Br2 battery in an acidic electrolyte.

[0098] Comparative Example 4

[0099] The aqueous Zn-Br2 battery in Comparative Example 4 is the same as the battery in Example 1, except that there is no heterojunction interface layer on the negative electrode.

[0100] Figure 10 This is a charge-discharge curve of the aqueous Zn-Br2 battery in Comparative Example 4 of the present invention; Figure 11 This is a cycle stability test curve of the aqueous Zn-Br2 battery in Comparative Example 4 of the present invention; wherein Figure 10 and Figure 11 The charging and discharging test conditions for the aqueous zinc-bromine battery are as follows: charging at 1.9V and 10mA / cm. 2 Discharge.

[0101] Depend on Figure 10 and Figure 11It can be seen that the Zn-Br2 battery in Comparative Example 4 has an areal capacity of 15 mAh / cm². 2 During the charge-discharge test, the battery's discharge plateau was 1.55V, its efficiency was 92.8%, and it completed less than 230 cycles.

[0102] Example 2

[0103] The aqueous Zn-Br2 battery in Example 2 is identical to the battery in Example 1, except that the aqueous electrolyte is acidic. Specifically, it utilizes a carbon felt positive electrode pretreated with TPABr3, a zinc negative electrode pre-deposited on the Sb / Sb2Zn3 heterojunction interface layer, and employs 0.5 mol / L ZnBr2 as both zinc and bromine sources, 0.25 mol / L TPABr as a zinc negative electrode stabilizer, and 0.2 mol / L H2SO4 to adjust the electrolyte to acidity. The charge-discharge curves of the aqueous Zn-Br2 battery in Example 2 are shown below. Figure 12 As shown.

[0104] Figure 12 This is a charge-discharge curve diagram of the acidic aqueous Zn-Br2 battery in Example 2 of the present invention, wherein... Figure 12 The charging and discharging test conditions for the aqueous zinc-bromine battery are as follows: charging at 1.9V and 10mA / cm. 2 Discharge.

[0105] like Figure 12 As shown, the battery in Example 2 can achieve a discharge voltage of 1.56V and a coulombic efficiency of 99.7%, which is similar to that in Example 1, indicating that the battery provided by the present invention can operate stably in neutral or acidic environments.

[0106] To further verify the feasibility of the technical solution of the present invention, a scale-up experiment was conducted on the battery in Example 1, scaling it up to 400mAh (electrode dimensions: 3.5cm × 4.5cm, area approximately 15.7cm²). 2 The positive and negative electrode capacities are 25mAh / cm², respectively. 2 .

[0107] Figure 13 The cycling curve of the soft-pack battery used in the scale-up experiment of the aqueous Zn-Br2 battery in Example 1 of this invention is shown.

[0108] like Figure 13 As shown, in this scaled-up experiment, the aqueous Zn-Br2 battery can operate stably for more than 3400 hours without significant capacity decay and achieves an energy density of 76 Wh / kg, indicating that the aqueous Zn-Br2 provided by this invention has the potential for practical application.

[0109] In summary, this invention assembles an aqueous Zn-Br2 battery by coating a solid bromide active material, tetrapropylammonium tribromide (TPABr3), onto a carbon felt as the positive electrode, pre-depositing zinc on the Sb / Sb2Zn3 heterojunction interface layer as the negative electrode, and using an electrolyte containing 0.5 mol / L ZnBr2 and 0.25 mol / L TPABr (tetrapropylammonium bromide). The assembled battery has the advantages of high areal capacity, coulombic efficiency, energy density, and cycle stability, and effectively avoids cross-contamination between the positive and negative electrodes. At the same time, it eliminates the need for an ion exchange membrane, reducing battery costs.

[0110] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An aqueous zinc-bromine battery, comprising: The positive electrode includes a first substrate and a solid-phase bromide active material coated on the first substrate; The negative electrode comprises a second substrate, a metal / zinc alloy heterojunction interface layer, and zinc electrodeposited on the metal / zinc alloy heterojunction interface layer; and The aqueous electrolyte is a mixed aqueous solution of zinc salt, bromide salt, pH adjuster and zinc negative electrode stabilizer; The solid-phase bromide active material is obtained by reacting a complexing agent with bromine. The solid-phase bromide active material is then mixed with a conductive agent, a binder, and a solvent and applied to the first substrate. The solid-phase bromide active material of the positive electrode can be completely converted into the discharge product Br during battery discharge. - And ammonium salt cations, Br in the electrolyte during charging - It complexes with the zinc negative electrode stabilizer in the electrolyte to form a solid-phase bromide active material that is deposited on the positive electrode; The complexing agent used in the preparation of solid-phase bromide active substances includes at least one of the following: Tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetraethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide; The metal / zinc alloy heterojunction interface layer includes at least one of the following: Mn / Mn-Zn alloy, Sb / Sb-Zn alloy, Mg / Mg-Zn alloy, Fe / Fe-Zn alloy, Cu / Cu-Zn alloy, Cr / Cr-Zn alloy, Ag / Ag-Zn alloy, Au / Au-Zn alloy; The zinc anode stabilizer includes at least one of the following: Tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetramethylammonium iodide, tetraethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide.

2. The battery according to claim 1, wherein: The mass ratio of the solid bromide active material to the conductive agent, binder, and solvent is 0.01-20:0.01-3:0.1-1:

100.

3. The battery according to claim 1, wherein: The first substrate and the second substrate are each independently selected from either a metal current collector or a non-metal current collector.

4. The battery according to claim 3, wherein: The non-metallic current collector includes carbon-based materials, which include at least one of the following: graphite, graphene, activated carbon, carbon microfibers, carbon nanofibers, graphite felt, carbon spheres, carbon nanotubes, and glassy carbon electrodes. The metal current collector includes at least one of silver, copper, titanium, gold, and platinum.

5. The battery according to claim 2, wherein: The conductive agent includes at least one of the following: Ketjen black, activated carbon, multi-walled carbon nanotubes, carbon nanospheres, amorphous carbon, graphene; The adhesive includes at least one of the following: Polyvinylidene fluoride, sodium carboxymethyl cellulose, polytetrafluoroethylene; The solvent includes at least one of the following: Water, 1-methyl-2-pyrrolidone.

6. The battery according to claim 1, wherein: The zinc salt includes at least one of the following: ZnSO4, ZnCl2, Zn(NO3)2, ZnBr2, ZnI2, Zn(CH3COO)2 and Zn(CF3SO3)2; The bromide salt includes at least one of the following: ZnBr2, KBr, NaBr, MnBr2, BaBr2, CuBr2, MgBr2, C4H 12 BrN, C8H 10 BrN, C 12 H 28 BrN and C 16 H 36 BrN.

7. The battery according to claim 1, wherein: The concentration of the zinc salt is 0.01-30 mol / L; The concentration of the bromide salt is 0.01-30 mol / L; The concentration of the zinc negative electrode stabilizer is 0.01-10 mol / L.

8. The battery according to claim 1, wherein: The aqueous electrolyte is neutral or acidic; The pH adjuster includes at least one of the following: H2SO4 solution, HCl solution, HNO3 solution, CH3COOH solution, H3PO4 solution, H2CO3 solution, H2SiO3 solution and HClO solution; The concentration of the pH adjuster is 0.01-10 mol / L.

9. The battery according to claim 1, wherein, The battery includes at least one of the following: Button batteries, cylindrical batteries, pouch batteries, prismatic batteries, and flow batteries.

10. The battery according to claim 4, wherein, The carbon microfibers include at least one of carbon cloth, carbon felt, and carbon paper.

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