Aqueous zinc-iodine battery electrolyte containing amino acid additive and preparation method and application thereof

Abstract

The invention relates to an aqueous zinc-iodine battery electrolyte containing an amino acid additive and a preparation method and application thereof, and belongs to the technical field of aqueous zinc-iodine batteries. The preparation method of the aqueous zinc-iodine battery electrolyte containing the amino acid additives comprises the following steps: fully stirring and mixing zinc salt, D-penicillamine and deionized water according to a certain proportion to obtain the aqueous zinc-iodine battery electrolyte containing the amino acid additives. The amino acid-containing additive D-penicillamine used in the invention is preferentially coordinated with I-, and due to the lack of free I-in the reaction, the generation of polyiodide and the dissolution of I2 are inhibited, so that the shuttle effect is inhibited; the amino acid-containing additive D-penicillamine also participates in a Zn < 2 + > solvation sheath layer, so that the tendency of desolvation and Zn < 2 + > migration is improved, and the generation of zinc negative electrode byproducts is inhibited; in addition, the aqueous zinc-iodine battery electrolyte containing the amino acid additive D-penicillamine is simple in preparation method and low in cost.

Description

Technical Field

[0001] The present application relates to the technical field of aqueous zinc-iodine batteries, and in particular to an aqueous zinc-iodine battery electrolyte containing an amino acid additive, and a preparation method and application thereof. Background Art

[0002] In recent years, aqueous zinc batteries have shown broad application prospects in the field of grid-scale energy storage due to their safety, environmental friendliness, and low cost. In addition, the low cost, abundant reserves, and high theoretical capacity of zinc metal further enhance its practical application value. Among all zinc-based batteries, zinc-iodine batteries (Zn-I2) with iodine as the positive electrode have abundant iodine (50-60 mg I2 / L seawater) and high specific capacity (211 mAh g -1 ) advantages. However, similar to lithium-sulfur batteries, zinc-iodine batteries face challenges related to side reactions and dendrite formation at the zinc anode, as well as the shuttle effect of multiple iodides at the cathode, which results in low coulombic efficiency and short cycle life. Therefore, solving the problems of multiple iodide shuttle effect and poor zinc reversibility is crucial for the development of advanced zinc-iodine batteries.

[0003] To address these problems, researchers have proposed a variety of strategies, including the design of conductive hosts, modification of separators, optimization of electrolytes (such as high-concentration salt / low-eutectic electrolytes or electrolyte additives), the use of polymer hydrogels, and the construction of artificial solid electrolyte interface (SEI) layers on zinc negative electrodes. Among these strategies, the electrolyte additive method is suitable for large-scale applications due to its low cost and simplicity. Summary of the Invention

[0004] In view of this, the present application provides an aqueous zinc-iodine battery electrolyte containing an amino acid additive, a preparation method thereof, and an application thereof. The amino acid additive D-penicillamine is introduced into the traditional electrolyte to prepare the optimized aqueous zinc-iodine battery electrolyte, which is applied to the zinc-iodine battery. This can improve the positive electrode multi-iodide shuttle effect and the zinc negative electrode side reaction, so that the aqueous zinc-iodine battery can achieve high stability, high rate performance and long cycle life, and can effectively overcome the defects of the above-mentioned prior art.

[0005] In a first aspect, the present application provides an aqueous zinc-iodine battery electrolyte containing an amino acid additive, comprising a zinc salt, an amino acid additive and deionized water, wherein the amino acid additive is D-penicillamine.

[0006] Preferably, the weight percentage of D-penicillamine in the electrolyte is 0.05-0.5 wt.%. More preferably, the weight percentage of D-penicillamine in the electrolyte is 0.1 wt.%.

[0007] Preferably, the zinc salt is selected from at least one of zinc trifluoromethanesulfonate, zinc chloride, and zinc sulfate. More preferably, the zinc salt is zinc sulfate.

[0008] Preferably, the concentration of the zinc salt is 1 to 3 mol / L. More preferably, the concentration of the zinc salt is 2 mol / L.

[0009] Theoretical support of the technical solution of this application: dissolving the amino acid additive D-penicillamine in zinc sulfate electrolyte, D-penicillamine preferentially reacts with I - Coordination forms chemical adsorption, due to Lack of free I in the reaction - , the production of polyiodide and the dissolution of I2 are inhibited, thereby inhibiting the shuttle effect and accelerating I - / I3 - The reversible conversion reaction between D-penicillamine and I2 increases the positive electrode reaction rate and reduces polarization. D-penicillamine adsorbs on the surface of the zinc negative electrode, reduces the direct reaction between polyiodide and zinc, and also participates in the Zn 2+ Solvation sheath, by weakening the Zn 2+ -H2O interaction and partial substitution of H2O molecules accelerates Zn 2+ The desolvation of the electrolyte inhibits the generation of related byproducts at the zinc negative electrode interface. The aqueous zinc-iodine battery prepared with the electrolyte containing the amino acid additive D-penicillamine has good cycle stability and rate performance, enabling the aqueous zinc-iodine battery to better meet commercial needs and achieve large-scale application.

[0010] The second aspect of the present application further provides a method for preparing the aqueous zinc-iodine battery electrolyte containing the amino acid additive, comprising the following steps:

[0011] Zinc salt, D-penicillamine and deionized water are fully stirred and mixed in a certain proportion to obtain an aqueous zinc-iodine battery electrolyte containing amino acid additives.

[0012] Preferably, the stirring time is 1 to 2 minutes.

[0013] Specifically, the method for preparing the aqueous zinc-iodine battery electrolyte containing the amino acid additive comprises the following steps:

[0014] (1) Prepare a 2 mol / L zinc sulfate solution at room temperature and normal pressure;

[0015] (2) Weigh a certain amount of the 2 mol / L zinc sulfate solution in (1) into a glass bottle, then add 0.1 wt.% of D-penicillamine, add a stirring magnet and stir thoroughly for 1 to 2 minutes to form a uniform mixed solution, i.e., an aqueous zinc-iodine battery electrolyte containing the amino acid additive D-penicillamine.

[0016] The third aspect of the present application also provides an aqueous zinc-iodine battery, comprising a positive electrode, a negative electrode, a separator arranged between the positive electrode and the negative electrode, and an electrolyte, wherein the electrolyte is the above-mentioned aqueous zinc-iodine battery electrolyte containing amino acid additives.

[0017] Preferably, the preparation process of the positive electrode is:

[0018] (1) Iodine and ultra-high capacity conductive carbon (UAC) were ground evenly in a mortar at a mass ratio of 1:1, and then calcined at 120 °C for 6 h to form carbon-supported iodine material AC / I2;

[0019] (2) Grind the carbon-supported iodine material, Ketjen black, and polytetrafluoroethylene (PTFE) in a mortar at a mass ratio of 7:2:1, add a small amount of water and mix to form a uniform black paste slurry, then coat the slurry on a stainless steel mesh and dry it naturally at room temperature to obtain a positive electrode.

[0020] Preferably, the negative electrode is a metal zinc sheet.

[0021] Preferably, the diaphragm is made of glass fiber.

[0022] Compared with the prior art, this application has the following beneficial effects:

[0023] The amino acid additive D-penicillamine used in this application is preferably - Coordination, due to Lack of free I in the reaction - , the production of polyiodide and the dissolution of I2 are inhibited, thereby inhibiting the shuttle effect; the amino acid additive D-penicillamine also participates in the Zn 2+ Solvation sheath, improves desolvation and Zn 2+ The tendency of migration is reduced, and the generation of zinc negative electrode by-products is suppressed; in addition, the preparation method of the aqueous zinc-iodine battery electrolyte containing the amino acid additive D-penicillamine in the present application is simple and low-cost, and the optimization of the zinc-iodine battery electrolyte can improve the cycle stability and rate performance of the aqueous zinc-iodine battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following briefly introduces the drawings required for use in the description of the present application or the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 The zinc-iodine battery assembled in Example 1 and Comparative Example 1 was -1 Charge and discharge cycle performance diagram under current density;

[0026] Figure 2 The zinc-iodine battery assembled in Example 1 and Comparative Example 1 has different current densities (0.1Ag -1 ~5Ag -1 ) performance graph;

[0027] Figure 3 The cyclic voltammetry curves of the zinc-iodine battery assembled in Example 1 and Comparative Example 1 are shown;

[0028] Figure 4 The chronoampere curve of the zinc-iodine battery assembled in Example 1 and Comparative Example 1 is shown;

[0029] Figure 5 The zinc-iodine battery assembled for Example 2 was 1Ag -1 Charge and discharge cycle performance diagram under current density;

[0030] Figure 6 The zinc-iodine battery assembled for Example 3 was 1Ag -1 Charge and discharge cycle performance diagram under current density;

[0031] Figure 7 The zinc-iodine battery assembled for Example 4 was 1Ag -1 Charge and discharge cycle performance diagram under current density. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0033] Unless otherwise specified, the experimental methods used in the examples of this application are all conventional methods.

[0034] In the following examples and comparative examples, unless otherwise specified, all raw materials can be purchased commercially or prepared by conventional methods.

[0035] Example 1

[0036] First, zinc sulfate heptahydrate was dissolved in deionized water to prepare a 2 mol / L zinc sulfate electrolyte, recorded as 2M ZnSO4; 5 mL of the 2 mol / L zinc sulfate electrolyte (mass of approximately 6.5 g) and approximately 6.5 mg (i.e., 0.1 wt.%) of D-penicillamine additive were weighed into a glass bottle, and a stirring magnet was added and stirred thoroughly for 1 to 2 minutes to obtain an aqueous zinc-iodine battery electrolyte containing 0.1 wt.% D-penicillamine additive, recorded as 2M ZnSO4+0.1 wt.% DPL.

[0037] Secondly, the iodine element and ultra-high capacity conductive carbon UAC were evenly ground in a mortar at a mass ratio of 1:1, and then calcined at 120°C and a heating rate of 5°C / min for 6 hours to form a carbon-supported iodine material AC / I2. The carbon-supported iodine material, Ketjen black, and polytetrafluoroethylene PTFE were evenly ground in a mortar at a mass ratio of 7:2:1, and a small amount of water was added to form a uniform black paste slurry. The slurry was then coated on a stainless steel mesh and naturally dried at room temperature to obtain a positive electrode.

[0038] Finally, the electrode sheet loaded with 10% PTFE binder was used as the positive electrode, the zinc sheet with a diameter of 12 mm was used as the negative electrode, the separator was made of glass fiber, and 2M ZnSO4+0.1wt.% DPL was used as the electrolyte to assemble button-type aqueous zinc-iodine batteries.

[0039] Example 2

[0040] First, zinc sulfate heptahydrate was dissolved in deionized water to prepare a 2 mol / L zinc sulfate electrolyte, recorded as 2MZnSO4; 5 mL of 2M zinc sulfate electrolyte (mass of approximately 6.5 g) and approximately 3.25 mg (i.e., 0.05 wt.%) of D-penicillamine additive were weighed into a glass bottle, and a stirring magnet was added and stirred thoroughly for 1 to 2 minutes to obtain an aqueous zinc-iodine battery electrolyte containing 0.05 wt.% D-penicillamine additive, recorded as 2M ZnSO4+0.05 wt.% DPL.

[0041] Secondly, the iodine element and ultra-high capacity conductive carbon UAC were evenly ground in a mortar at a mass ratio of 1:1, and then calcined at 120°C and a heating rate of 5°C / min for 6 hours to form a carbon-supported iodine material AC / I2. The carbon-supported iodine material, Ketjen black, and polytetrafluoroethylene PTFE were evenly ground in a mortar at a mass ratio of 7:2:1, and a small amount of water was added to form a uniform black paste slurry. The slurry was then coated on a stainless steel mesh and naturally dried at room temperature to obtain a positive electrode.

[0042] Finally, a button-type aqueous zinc-iodine battery was assembled using a pole piece loaded with 10% PTFE binder as the positive electrode, a zinc sheet with a diameter of 12 mm as the negative electrode, a separator made of glass fiber, and 2M ZnSO4+0.05wt.% DPL as the electrolyte.

[0043] like Figure 5 As shown, at 1Ag -1 The charge and discharge cycle test was carried out at a current density of 1.5447 W / m. After 1000 cycles, the zinc-iodine battery assembled with 0.05 wt.% D-penicillamine additive had a discharge specific capacity of 135.8 mAh / g.

[0044] Example 3

[0045] First, zinc sulfate heptahydrate was dissolved in deionized water to prepare a 2 mol / L zinc sulfate electrolyte, recorded as 2MZnSO4; 5 mL of 2M zinc sulfate electrolyte (mass of approximately 6.5 g) and approximately 19.5 mg (i.e., 0.3 wt.%) of D-penicillamine additive were weighed into a glass bottle, and a stirring magnet was added and stirred thoroughly for 1 to 2 minutes to obtain an aqueous zinc-iodine battery electrolyte containing 0.3 wt.% D-penicillamine additive, recorded as 2M ZnSO4+0.3 wt.% DPL.

[0046] Secondly, the iodine element and ultra-high capacity conductive carbon UAC were evenly ground in a mortar at a mass ratio of 1:1, and then calcined at 120°C and a heating rate of 5°C / min for 6 hours to form a carbon-supported iodine material AC / I2. The carbon-supported iodine material, Ketjen black, and polytetrafluoroethylene PTFE were evenly ground in a mortar at a mass ratio of 7:2:1, and a small amount of water was added to form a uniform black paste slurry. The slurry was then coated on a stainless steel mesh and naturally dried at room temperature to obtain a positive electrode.

[0047] Finally, a button-type aqueous zinc-iodine battery was assembled using a pole piece loaded with 10% PTFE binder as the positive electrode, a zinc sheet with a diameter of 12 mm as the negative electrode, a separator made of glass fiber, and 2M ZnSO4+0.3wt.% DPL as the electrolyte.

[0048] like Figure 6 As shown, at 1Ag -1 The charge and discharge cycle test was carried out at a current density of 1.5447 W / m. After 1000 cycles, the zinc-iodine battery assembled with 0.3 wt.% D-penicillamine additive had a discharge specific capacity of 124.3 mAh / g.

[0049] Example 4

[0050] First, zinc sulfate heptahydrate was dissolved in deionized water to prepare a 2 mol / L zinc sulfate electrolyte, recorded as 2M ZnSO4; 5 mL of 2M zinc sulfate electrolyte (mass of approximately 6.5 g) and approximately 32.5 mg (i.e., 0.5 wt.%) of D-penicillamine additive were weighed into a glass bottle, and a stirring magnet was added and stirred thoroughly for 1 to 2 minutes to obtain an aqueous zinc-iodine battery electrolyte containing 0.5 wt.% D-penicillamine additive, recorded as 2M ZnSO4+0.5 wt.% DPL.

[0051] Secondly, the iodine element and ultra-high capacity conductive carbon UAC were evenly ground in a mortar at a mass ratio of 1:1, and then calcined at 120°C and a heating rate of 5°C / min for 6 hours to form a carbon-supported iodine material AC / I2. The carbon-supported iodine material, Ketjen black, and polytetrafluoroethylene PTFE were evenly ground in a mortar at a mass ratio of 7:2:1, and a small amount of water was added to form a uniform black paste slurry. The slurry was then coated on a stainless steel mesh and naturally dried at room temperature to obtain a positive electrode.

[0052] Finally, a button-type aqueous zinc-iodine battery was assembled using a pole piece loaded with 10% PTFE binder as the positive electrode, a zinc sheet with a diameter of 12 mm as the negative electrode, a separator made of glass fiber, and 2M ZnSO4+0.5wt.% DPL as the electrolyte.

[0053] like Figure 7 As shown, at 1Ag -1 The charge and discharge cycle test was carried out at a current density of 1.5447 W / m. After 1000 cycles, the zinc-iodine battery assembled with 0.5 wt.% D-penicillamine additive had a discharge specific capacity of 133.1 mAh / g.

[0054] Comparative Example 1

[0055] First, zinc sulfate heptahydrate was dissolved in deionized water and stirred thoroughly to prepare a zinc sulfate electrolyte with a concentration of 2 mol / L, which was recorded as 2M ZnSO4.

[0056] Secondly, the iodine element and ultra-high capacity conductive carbon UAC were evenly ground in a mortar at a mass ratio of 1:1, and then calcined at 120°C, 5°C / min for 6 hours to form a carbon-supported iodine material AC / I2. The carbon-supported iodine material, Ketjen black, and polytetrafluoroethylene PTFE were evenly ground in a mortar at a mass ratio of 7:2:1, and a small amount of water was added to form a uniform black paste slurry. The slurry was then coated on a stainless steel mesh and naturally dried at room temperature to obtain a positive electrode.

[0057] Finally, the electrode sheet loaded with 10% PTFE binder was used as the positive electrode, the zinc sheet with a diameter of 12 mm was used as the negative electrode, the separator was made of glass fiber, and 2M ZnSO4 was used as the electrolyte to assemble button-type aqueous zinc-iodine batteries.

[0058] Test Case

[0059] The electrochemical performance of the aqueous zinc-iodine battery assembled in Example 1 and Comparative Example 1 was tested, and the electrochemical performance is shown in the figure:

[0060] like Figure 1 As shown, at 1Ag -1 In charge-discharge cycling tests at a current density of 1.5 Å, the zinc-iodine battery containing 0.1 wt.% D-penicillamine additive maintained a high discharge capacity of 138.2 mAh / g after 1,000 cycles, demonstrating excellent cycling stability. In contrast, the zinc-iodine battery containing 2 mol / L zinc sulfate exhibited significant capacity decay from the outset.

[0061] like Figure 2 As shown in the figure, the zinc-iodine battery assembled with 0.1wt.% D-penicillamine additive has excellent rate performance. -1 It can still maintain 114.7mAh g under high current discharge conditions -1 The discharge capacity, when the current density is restored to 0.1Ag -1 After that, the discharge capacity can reach 161.9 mAh g again. -1 . The zinc-iodine battery assembled with 2 mol / L zinc sulfate is -1 Under high current discharge conditions, it only maintains 79.1mAh g -1 The discharge capacity, when the current density is restored to 0.1Ag -1 After that, the discharge capacity is only 108.1 mAh g -1 .

[0062] like Figure 3 As shown, the cyclic voltammetry curves of aqueous zinc-iodine full cells were tested at a scan rate of 0.2 mV. The zinc-iodine cell assembled with 0.1 wt.% D-penicillamine additive had a smaller potential difference between the oxidation and reduction peaks, approximately 30 mV, indicating less electrode polarization. The 0.1 wt.% D-penicillamine additive has efficient electron transfer, improving the kinetics of the iodine conversion reaction. Furthermore, the redox peak intensity was stronger, indicating that the zinc-iodine cell assembled with 0.1 wt.% D-penicillamine additive had better conductivity. In contrast, the zinc-iodine cell assembled with 2 mol / L zinc sulfate had a potential difference between the oxidation and reduction peaks of approximately 41 mV, indicating greater electrode polarization than that with 0.1 wt.% D-penicillamine additive and slower reaction kinetics.

[0063] like Figure 4 As shown, Zn was analyzed by chronoamperometry (CA). 2+ Diffusion and deposition mechanism on the electrode surface. Within 300s, the current density of the zinc negative electrode in the zinc-iodine battery assembled with 2 mol / L zinc sulfate continued to increase, which indicates that Zn2+ It tends to diffuse horizontally along the electrode surface in two dimensions and migrate to a position that is more conducive to charge transfer, resulting in the aggregation of metallic zinc. The tip effect exacerbates the tip growth, thus generating dendrites. On the contrary, in the zinc-iodine battery assembled with the electrolyte containing 0.1wt.% D-penicillamine additive, the current density is relatively stable, and three-dimensional diffusion occurs after a rapid two-dimensional diffusion process. This indicates that the D-penicillamine molecules adsorbed on the zinc negative electrode inhibit the lateral diffusion and induce the Zn 2+ Uniform deposition in the vertical direction.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An aqueous zinc-iodine battery electrolyte containing an amino acid additive, characterized in that: The invention comprises zinc salt, amino acid additive and deionized water, wherein the amino acid additive is D-penicillamine.

2. The aqueous zinc-iodine battery electrolyte containing amino acid additives according to claim 1, characterized in that The weight percentage of D-penicillamine in the electrolyte is 0.05-0.5 wt.%.

3. The aqueous zinc-iodine battery electrolyte containing amino acid additives according to claim 1, characterized in that: The zinc salt is selected from at least one of zinc trifluoromethanesulfonate, zinc chloride, and zinc sulfate.

4. The aqueous zinc-iodine battery electrolyte containing amino acid additives according to claim 1, characterized in that: The concentration of the zinc salt is 1-3 mol / L.

5. A method for preparing an aqueous zinc-iodine battery electrolyte containing an amino acid additive according to any one of claims 1 to 4, characterized in that: The following steps are involved: Zinc salt, D-penicillamine and deionized water are fully stirred and mixed in a certain proportion to obtain an aqueous zinc-iodine battery electrolyte containing amino acid additives.

6. The method for preparing an aqueous zinc-iodine battery electrolyte containing an amino acid additive according to claim 5, wherein: The stirring time is 1 to 2 minutes.

7. An aqueous zinc-iodine battery, characterized in that: The invention comprises a positive electrode, a negative electrode, a separator arranged between the positive electrode and the negative electrode, and an electrolyte, wherein the electrolyte is the aqueous zinc-iodine battery electrolyte containing amino acid additives according to any one of claims 1 to 4.

8. The aqueous zinc-iodine battery according to claim 7, characterized in that: The preparation process of the positive electrode is as follows: (1) Iodine and ultra-high capacity conductive carbon (UAC) were ground evenly in a mortar at a mass ratio of 1:1, and then calcined at 120 °C for 6 h to form carbon-supported iodine material AC / I2; (2) Grind the carbon-supported iodine material, Ketjen black, and polytetrafluoroethylene (PTFE) in a mortar at a mass ratio of 7:2:1, add a small amount of water and mix to form a uniform black paste slurry, then coat the slurry on a stainless steel mesh and dry it naturally at room temperature to obtain a positive electrode.

9. The aqueous zinc-iodine battery according to claim 7, characterized in that: The negative electrode is a metal zinc sheet.

10. The aqueous zinc-iodine battery according to claim 7, characterized in that: The diaphragm is made of glass fiber.

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