Low-temperature aqueous electrolyte for anchoring I < + > ions based on double-coordination structure and low-temperature four-electron aqueous zinc-iodine battery

Abstract

The invention belongs to the technical field of electrochemical energy storage, and particularly relates to a low-temperature aqueous electrolyte for anchoring I < + > ions based on a double-coordination structure and a low-temperature four-electron aqueous zinc-iodine battery. The low-temperature aqueous electrolyte is a mixed solution of a zinc salt, an electrolyte additive and water, and the low-temperature aqueous electrolyte comprises 2-5 mol / L of the zinc salt and 0.3-0.6 mol / L of the electrolyte additive; the zinc salt is zinc perchlorate or zinc tetrafluoroborate. The low-temperature four-electron aqueous zinc-iodine battery comprises the low-temperature aqueous electrolyte. Compared with the prior art, the invention at least has the following beneficial effects: (1) the corrosion risk caused by chloride ion concentration is reduced; (2) efficient four-electron iodine positive electrode reaction is realized; and (3) obtaining the low-temperature four-electron aqueous zinc-iodine battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical energy storage, and particularly relates to a low-temperature aqueous electrolyte based on a double coordination structure for anchoring I + ions and a low-temperature four-electron aqueous zinc-iodine battery. Background Art

[0002] Due to their intrinsic safety and environmental friendliness, aqueous batteries have rapidly become favorable candidates for large-scale energy storage. However, for some extremely cold environments (such as winter in the north, polar regions, high-altitude areas, and future deep-space exploration, etc.), aqueous batteries usually face problems such as rapid capacity decay and slow charge and discharge rates. The main reasons include: poor low-temperature performance of the electrolyte; the aqueous electrolyte is prone to freezing at low temperatures, resulting in low ionic conductivity, high viscosity, and poor electrode / electrolyte interface contact, causing the battery to malfunction at low temperatures. Therefore, developing antifreeze electrolytes has become the core issue in constructing low-temperature aqueous batteries.

[0003] Aqueous zinc-iodine batteries exhibit characteristics such as good environmental tolerance, high theoretical specific capacity, high abundance, and low cost, and are currently widely concerned. The fast kinetics of the iodine positive electrode reaction is also considered one of the favorable candidates for low-temperature aqueous batteries. However, the voltage of traditional two-electron aqueous zinc-iodine batteries based on I - / I2 is not satisfactory (1.3V). Due to the rich redox reactions of iodine, activating high-valent iodine reactions to achieve high-potential and high-theoretical-capacity aqueous zinc-iodine batteries have been successively reported. This type of work mainly anchors I + through electrolyte design to achieve a four-electron positive electrode reaction of I - / I2 / I + and realize a four-electron aqueous zinc-iodine battery with high potential and high theoretical specific capacity. However, this design often requires a relatively high concentration of free halogen ions to achieve stable I + ions in the aqueous electrolyte. For example, in Chinese Patent Application: CN111540950A, 19 mLiCl is added to the electrolyte. However, a large number of free chloride ions will cause serious damage to the surface of the zinc negative electrode due to pitting corrosion. In addition, it will also corrode the other components of the battery, thereby affecting the cycle stability of the entire battery. Therefore, it is very necessary to develop a new scheme for anchoring I + . Recently, Chinese Patent Application: CN117458003A also successfully reported the design of a eutectic electrolyte through dimethyl sulfone, nicotinamide, and zinc perchlorate, achieving a solid I + effect through I-N coordination and activating I +High-cost platforms. However, the eutectic electrolyte limits the intrinsic conductivity of the aqueous electrolyte, resulting in a significant decline in the rate performance of the full cell. Therefore, there is still a lack of an ideal solution for developing and designing a high-potential four-electron aqueous zinc-iodine battery electrolyte while retaining the advantages of the aqueous zinc-iodine battery itself.

[0004] The existing technologies have the following problems:

[0005] (1) The reversibility of the I - / I2 / I + reaction is insufficient, and there is a lack of an efficient solution for anchoring I + ;

[0006] (2) High-concentration halogen ions (such as Cl - ) corrode the zinc negative electrode, reducing the cycle stability;

[0007] (3) The eutectic electrolyte has low conductivity, resulting in unsatisfactory rate performance of the battery;

[0008] (4) At low temperatures, the traditional electrolyte freezes, the ion migration is blocked, and the battery cannot operate below -50°C.

[0009] The above defects stem from the limitations of electrolyte design: the failure to balance the stability of I + , low corrosiveness, and high ionic conductivity at low temperatures. SUMMARY OF THE INVENTION

[0010] The object of the present invention is to solve the above problems, specifically including:

[0011] (1) How to stabilize I + at a low halogen ion concentration and avoid the corrosion of the zinc negative electrode;

[0012] (2) How to design an electrolyte with both high conductivity and low-temperature antifreeze properties;

[0013] (3) How to achieve high capacity and long cycle life of the full cell at -50°C.

[0014] To this end, the first aspect of the present invention provides a low-temperature aqueous electrolyte based on a double coordination structure for anchoring I + ions, providing a completely new method for stabilizing I +In this way, the low-temperature aqueous electrolyte is a mixed solution of zinc salt, electrolyte additive and water. In the low-temperature aqueous electrolyte: the zinc salt is 2-5 mol / L, and the electrolyte additive is 0.3-0.6 mol / L; the zinc salt is zinc perchlorate or zinc tetrafluoroborate; the electrolyte additive includes at least one of trimethylamine hydrochloride, triethylamine hydrochloride, propylamine hydrochloride, methoxylamine hydrochloride, butylamine hydrochloride and triethanolamine hydrochloride. The above low-temperature aqueous electrolyte has both high conductivity and low-temperature antifreeze properties. The use temperature of this electrolyte can be as low as -50 °C, and high capacity and long cycle life of the full cell at -50 °C can be achieved; at room temperature of 25 °C, the zinc-zinc symmetric battery can stably cycle for more than 1000 hours.

[0015] As a preferred solution, when the zinc salt is zinc perchlorate, at room temperature of 25 °C, the zinc-zinc symmetric battery can stably cycle for more than 2000 hours.

[0016] In order to achieve high capacity and long cycle life of the full cell at -60 °C, the present invention provides a more preferred low-temperature aqueous electrolyte:

[0017] Solution I: In the low-temperature aqueous electrolyte: zinc perchlorate is 3-5 mol / L, and the electrolyte additive is 0.3-0.6 mol / L. The zinc-zinc symmetric battery obtained by Solution I at room temperature of 25 °C can stably cycle for more than 2000 hours; at -60 °C, the obtained aqueous zinc-iodine battery exhibits good cycle stability, and there is basically no obvious capacity decay after 800 cycles.

[0018] Solution II: In the low-temperature aqueous electrolyte: zinc tetrafluoroborate is 3-5 mol / L, and the electrolyte additive is 0.3-0.6 mol / L. The zinc-zinc symmetric battery obtained by Solution II at room temperature of 25 °C can stably cycle for more than 1000 hours; at -60 °C, the obtained aqueous zinc-iodine battery exhibits good cycle stability, and there is basically no obvious capacity decay after 500 cycles.

[0019] Solution III: In the low-temperature aqueous electrolyte: zinc perchlorate is 2-5 mol / L, and trimethylamine hydrochloride is 0.3-0.6 mol / L. The zinc-zinc symmetric battery obtained by Solution III at room temperature of 25 °C can stably cycle for more than 2000 hours; at -60 °C, the obtained aqueous zinc-iodine battery exhibits good cycle stability, and there is basically no obvious capacity decay after 800 cycles.

[0020] There are intersections between the technical solutions of Solution III and Solution I. Both select zinc perchlorate. Solution I is the optimization of the concentration of zinc perchlorate to obtain a better technical solution; Solution III is the optimization of the electrolyte additive to obtain a better technical solution. That is, when the concentration of zinc perchlorate is between 2 - 3 mol / L (excluding 3 mol / L), using trimethylamine hydrochloride as a specific electrolyte additive can also achieve the corresponding technical effects.

[0021] As a further preferred solution, the electrolyte additive is trimethylamine hydrochloride or triethylamine hydrochloride.

[0022] The raw material water of the above low-temperature aqueous electrolyte is preferably deionized water without other impurity ions.

[0023] The inventive points of this application include:

[0024] (1) Changing the anchoring I + Method: This invention uses low-concentration trimethylamine hydrochloride (TMA·HCl) or triethylamine hydrochloride (TEA·HCl) as electrolyte additives. Through the double coordination of amino groups (-NH3 + ) and Cl-, I + is stabilized to form a complex (such as [TMA·I + ·Cl]), reducing the hydrolysis risk of I + and the corrosion risk brought by the chloride ion concentration;

[0025] (2) Changing the electrolyte salt formula: Using zinc perchlorate or zinc tetrafluoroborate with a concentration of 2 - 5 mol / L as the main salt, the concentration of the electrolyte additive is 0.3 - 0.6 mol / L, and combined water (such as deionized water) is used as the solvent to achieve an efficient four-electron reaction at a low Cl - concentration (<1 mol / L);

[0026] (3) Realizing a low-temperature four-electron aqueous zinc-iodine battery: In the optimized electrolyte system, the four-electron aqueous zinc-iodine battery can achieve stable cycling at -50°C or even -60°C.

[0027] When the electrolyte additive is specifically trimethylamine hydrochloride (TMA·HCl), the reversible electrochemical equation for stabilizing I + is as follows:

[0028]

[0029] The preparation method of the above low-temperature aqueous electrolyte based on the double coordination structure for anchoring I + ions can be: mixing zinc perchlorate or zinc tetrafluoroborate, the electrolyte additive, and water.

[0030] The second aspect of the present invention provides a low-temperature four-electron aqueous zinc-iodine battery, and the low-temperature four-electron aqueous zinc-iodine battery includes the above-mentioned low-temperature aqueous electrolyte based on the double coordination structure for anchoring I + ions.

[0031] As a preferred solution, the low-temperature four-electron aqueous zinc-iodine battery satisfies at least one of the following conditions:

[0032] The positive electrode material is a porous carbon material loaded with iodine;

[0033] The negative electrode material is zinc foil or other metal foils electroplated with a certain capacity of zinc.

[0034] As a preferred solution, the porous carbon material includes at least one of activated carbon, carbon felt, and carbon fiber.

[0035] As a preferred solution, the other metal foils include at least one of copper foil and titanium foil.

[0036] As a preferred solution, the separator used in the low-temperature four-electron aqueous zinc-iodine battery is glass fiber.

[0037] The assembly method of the above-mentioned low-temperature four-electron aqueous zinc-iodine battery is a technical means commonly used by those skilled in the art, and only the electrolyte is different from the prior art.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] (1) Reducing the corrosion risk caused by the chloride ion concentration:

[0040] The present invention uses low-concentration trimethylamine hydrochloride (TMA·HCl) or triethylamine hydrochloride (TEA·HCl) as an electrolyte additive, and stabilizes I through the double coordination of the amino group (-NH3 + ) with Cl- + , forming a complex (such as [TMA·I + ·Cl]), reducing the hydrolysis risk of I + , and reducing the corrosion risk caused by the chloride ion concentration;

[0041] (2) Achieving an efficient four-electron reaction:

[0042] Using zinc perchlorate or zinc tetrafluoroborate with a concentration of 2-5 mol / L as the main salt, the concentration of the electrolyte additive is 0.3-0.6 mol / L, and combining water as the solvent, an efficient four-electron reaction is achieved at a low Cl - concentration (<1 mol / L);

[0043] (3) Obtaining a low-temperature four-electron aqueous zinc-iodine battery:

[0044] In an optimized electrolyte system, a four-electron aqueous zinc-iodine battery can achieve stable cycling at -50 °C or even -60 °C.

[0045] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other objects, features, and advantages of the present invention more obvious and understandable, the following specifically illustrates the specific embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application.

[0047] Figure 1 a shows the cyclic voltammogram of the zinc-iodine battery of Comparative Example 1 at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate;

[0048] Figure 1 b shows the galvanostatic charge-discharge curve of the zinc-iodine battery of Comparative Example 1 at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate;

[0049] Figure 2 a shows the cyclic voltammogram of the zinc-iodine battery of Comparative Example 4 at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L sodium chloride;

[0050] Figure 2 b shows the galvanostatic charge-discharge curve of the zinc-iodine battery of Comparative Example 4 at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L sodium chloride;

[0051] Figure 3a shows the cyclic voltammogram of a zinc-iodine battery at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride;

[0052] Figure 3b shows the galvanostatic charge-discharge curve of a zinc-iodine battery at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride;

[0053] Figure 4 a shows the in-situ Raman spectrum of the iodine positive electrode of a four-electron zinc-iodine battery at a temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride;

[0054] Figure 4 b shows the traditional chloride ion single coordination to fix I +Ionic structure;

[0055] Figure 4 c shows the dual coordination structure of the electrolyte-fixed I + ions of the present invention;

[0056] Figure 5 shows the cycle stability of a zinc-zinc symmetric battery when the temperature is 25 °C and the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride;

[0057] Figure 6 shows optical photographs of different electrolytes at different temperatures;

[0058] Figure 7 shows the charge-discharge curves of a four-electron zinc-iodine battery at different rates when the temperature is -60 °C and the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride;

[0059] Figure 8 shows the cycle stability of a four-electron zinc-iodine battery at a current density of 0.5 A / g when the temperature is -60 °C and the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride. Detailed implementation manners

[0060] In the following description, a large number of specific details are given to provide a more thorough understanding of the technical solutions provided by the present invention. However, it is obvious to those skilled in the art that the technical solutions provided by the present invention can be implemented without one or more of these details.

[0061] In the examples and comparative examples of the present invention, electrochemical performance comparison is involved. Without special instructions, the positive electrode is porous carbon loaded with iodine (I2 / AC), the negative electrode is zinc foil, the separator is glass fiber, and the electrolyte composition is different. The positive electrode, negative electrode, and separator are all commercially available conventional materials.

[0062] Among them, Zn(ClO4)2 is zinc perchlorate, Zn(BF4)2 is zinc tetrafluoroborate, TMA·HCl is trimethylamine hydrochloride, TEA·HCl is triethylamine hydrochloride, PA·HCl is propylamine hydrochloride, MOA·HCl is methoxyamine hydrochloride, BA·HCl is butylamine hydrochloride, and TAA·HCl is triethanolamine hydrochloride. Each raw material is commercially available.

[0063] In Example 1 of the present invention, 2 mol / L Zn(ClO4)2 + 0.3 mol / L TMA·HCl means that the concentration of Zn(ClO4)2 in the electrolyte is 2 mol / L, the concentration of TMA·HCl is 0.3 mol / L, the solvent is deionized water, and the same applies to other examples and comparative examples.

[0064] In the embodiments and comparative examples of the present invention, the testing and calculation methods are as follows: At room temperature of 25 °C, with a current density of 1 A / g, constant current charge and discharge are carried out, the charging cut-off voltage is 1.85 V, and the discharging cut-off voltage is 0.6 V.

[0065] Discharge specific capacity: The actual capacity of the battery discharge divided by the mass of the positive active material iodine

[0066] Coulombic efficiency: Discharge capacity divided by charge capacity

[0067] State at low temperature: Place the electrolyte at this temperature.

[0068] In the embodiments and comparative examples of the present invention, the theoretical specific capacity of the two-electron zinc-iodine battery is 211 mAh / g, and the theoretical specific capacity of the four-electron zinc-iodine battery is 422 mAh / g. If the iodine positive ions are fully fixed, the discharge specific capacity of the full battery needs to be close to 400 mAh / g, such as 385 mAh / g.

[0069] Table 1 shows the discharge specific capacity (mAh / g), Coulombic efficiency (%), and state at low temperature of the electrolytes of each embodiment;

[0070] Table 2 shows the discharge specific capacity (mAh / g), Coulombic efficiency (%), and state at low temperature of the electrolytes of each comparative example.

[0071] Table 1

[0072]

[0073]

[0074] Table 2

[0075]

[0076]

[0077] Test Example 1 (for Comparative Example 1)

[0078] Figure 1 a shows the cyclic voltammetry curve of the zinc-iodine battery of Comparative Example 1 when the electrolyte contains 2 mol / L zinc perchlorate at room temperature of 25 °C;

[0079] Figure 1 b shows the constant current charge and discharge curve of the zinc-iodine battery of Comparative Example 1 when the electrolyte contains 2 mol / L zinc perchlorate at room temperature of 25 °C.

[0080] As Figure 1As shown, at room temperature of 25 °C, cyclic voltammetry and galvanostatic charge-discharge of the aqueous zinc-iodine battery only exhibit a pair of reversible redox reactions, with the potential at 1.3 / 1.1 V, corresponding to the reaction of I - / I2, which is a typical two-electron zinc-iodine battery.

[0081] Test Example 2 (for Comparative Example 4)

[0082] Figure 2 a shows the cyclic voltammogram of the zinc-iodine battery of Comparative Example 4 at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L sodium chloride;

[0083] Figure 2 b shows the galvanostatic charge-discharge curve of the zinc-iodine battery of Comparative Example 4 at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L sodium chloride.

[0084] As Figure 2 shown, at room temperature of 25 °C, cyclic voltammetry and galvanostatic charge-discharge of the aqueous zinc-iodine battery exhibit two pairs of reversible redox reactions, with the potentials at 1.3 / 1.1 V and 1.8 / 1.6 V respectively, corresponding to the reactions of I - / I2 and I2 / I + . However, the redox peak current of I2 / I + is small, and the charge-discharge specific capacity of the full battery is only 261 mAh / g, indicating that I + is not fully fixed, and the single coordination of low-concentration chloride ions is not sufficient to completely stabilize I + .

[0085] Test Example 3 (for Example 1)

[0086] Figure 3a shows the cyclic voltammogram of the zinc-iodine battery at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride;

[0087] Figure 3b shows the galvanostatic charge-discharge curve of the zinc-iodine battery at room temperature of 25 °C when the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride.

[0088] As shown in Figure 3, at room temperature of 25 °C, cyclic voltammetry and galvanostatic charge-discharge of the aqueous zinc-iodine battery exhibit two pairs of reversible redox reactions, with the potentials at 1.3 / 1.1 V and 1.8 / 1.6 V respectively, corresponding to the reactions of I - / I2 and I2 / I + . And, the redox peak current of I2 / I + is strong, and the peak area is almost the same as that of I - / I2 is the same. In addition, the charge-discharge specific capacity of the full cell reaches more than 400 mAh / g, indicating that I + is fully fixed, enabling the full cell to reach the theoretical specific capacity, verifying the achievement of the electrolyte design. It is speculated that the co-action of TMA and chloride ions stabilizes I + .

[0089] Test Example 4 (for Example 1)

[0090] Drop the positive electrode paste on the glassy carbon electrode. The electrolyte composition is 2 mol / L Zn(ClO4)2 + 0.3 mol / L TMA·HCl. The counter electrode and reference electrode are zinc foils, and in-situ Raman testing is performed on the assembled battery.

[0091] Figure 4 a shows the in-situ Raman spectrum of the iodine positive electrode of a four-electron zinc-iodine battery when the temperature is 25 °C and the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride;

[0092] Figure 4 b shows the traditional single coordination of chloride ions to fix I + ionic structure;

[0093] Figure 4 c shows the double coordination structure of the electrolyte of the present invention to fix I + ionic structure.

[0094] As Figure 4 shown in a, as the potential increases, a signal peak appears at 170 cm -1 , corresponding to [TMA·I + ·Cl]. As the potential increases, the signal peak gradually strengthens. At the end of discharge, the signal peak gradually disappears, corresponding to the end of the reversible reaction of I2 / I + , proving that the double coordination structure stabilizes I + . The specific coordination structure is as shown in Figure 4 b-4c. Figure 4 b is the traditional single coordination of ICl, Figure 4 c is the double coordination structure of the electrolyte constructed in the present invention.

[0095] Test Example 5 (for Example 1)

[0096] Assemble a symmetric cell using zinc foil. The electrolyte composition is 2 mol / L Zn(ClO4)2 + 0.3

[0097] mol / L TMA·HCl, and the separator is glass fiber.

[0098] Figure 5The cycling stability of a zinc-zinc symmetric battery is shown when the temperature is 25 °C and the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride.

[0099] As Figure 5 shown, at room temperature of 25 °C, the symmetric battery can be stably cycled for more than 2000 hours, proving that there is no corrosive effect on the zinc negative electrode under low-concentration chloride ion conditions.

[0100] Test Example 6 (for Comparative Example 1 and Example 1)

[0101] Figure 6 Optical photos of different electrolytes at different temperatures are shown.

[0102] The blank electrolyte 2 mol / L Zn(ClO4)2 and 2 mol / L Zn(ClO4)2 + 0.3

[0103] mol / L TMA·HCl are respectively placed at room temperature. As Figure 6 shown, both are colorless transparent liquids; when they are both placed at -60 °C, it can be seen that 2 mol / L Zn(ClO4)2 has frozen, while 2 mol / L Zn(ClO4)2 + 0.3 mol / L TMA·HCl still maintains a stable liquid flow state, proving that the electrolyte described in the present invention has the potential for low-temperature applications.

[0104] Test Example 7 (for Example 1)

[0105] The positive electrode uses an iodine-activated carbon composite material (I2 / AC), the negative electrode uses a zinc foil, the electrolyte composition is 2 mol / L Zn(ClO4)2 + 0.3 mol / L TMA·HCl, and the separator is glass fiber to assemble an aqueous zinc-iodine battery.

[0106] Figure 7 The charge-discharge curves of a four-electron zinc-iodine battery at different rates are shown when the temperature is -60 °C and the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride.

[0107] As Figure 7 shown, at low temperature of -60 °C, the aqueous zinc-iodine battery exhibits good rate performance. From 0.01 - 0.5 A / g, good four-electron charge-discharge curves can be shown, and the specific capacity remains above 150 mAh / g.

[0108] Test Example 8 (for Example 1)

[0109] The positive electrode uses an iodine-activated carbon composite material (I2 / AC), the negative electrode uses zinc foil, the electrolyte composition is 2 mol / L Zn(ClO4)2 + 0.3 mol / L TMA·HCl, and the separator is glass fiber to assemble an aqueous zinc-iodine battery.

[0110] Figure 8 It shows the cycle stability of a four-electron zinc-iodine battery at a current density of 0.5 A / g when the temperature is -60 °C and the electrolyte contains 2 mol / L zinc perchlorate and 0.3 mol / L trimethylamine hydrochloride.

[0111] As Figure 8 shown, at a low temperature of -60 °C, the aqueous zinc-iodine battery exhibits good cycle stability, and there is basically no obvious capacity decay after 800 cycles.

[0112] Test Example 9 (for Example 17)

[0113] The difference from Test Example 5 is that the electrolyte contains 2 mol / L zinc tetrafluoroborate and 0.3 mol / L trimethylamine hydrochloride.

[0114] At room temperature of 25 °C, the symmetric battery can stably cycle for more than 1000 hours, proving that there is no corrosion effect on the zinc negative electrode under low-concentration chloride ion conditions.

[0115] Test Example 10 (for Example 19)

[0116] The difference from Test Example 8 is that the electrolyte contains 3.5 mol / L zinc tetrafluoroborate and 0.3 mol / L trimethylamine hydrochloride.

[0117] At a low temperature of -60 °C, the aqueous zinc-iodine battery exhibits good cycle stability, and there is basically no obvious capacity decay after 500 cycles.

[0118] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low-temperature aqueous electrolyte based on a double coordination structure for anchoring I + ions, characterized in that The low-temperature aqueous electrolyte is a mixed solution of zinc salt, electrolyte additive and water. In the low-temperature aqueous electrolyte: The zinc salt is 2-5 mol / L, and the electrolyte additive is 0.3-0.6 mol / L; The zinc salt is zinc perchlorate or zinc tetrafluoroborate; The electrolyte additive includes at least one of trimethylamine hydrochloride, triethylamine hydrochloride, propylamine hydrochloride, methoxyamine hydrochloride, butylamine hydrochloride and triethanolamine hydrochloride.

2. The low-temperature aqueous electrolyte based on the double coordination structure for anchoring I + ions, characterized in that In the low-temperature aqueous electrolyte: the zinc salt is 3-5 mol / L, and the electrolyte additive is 0.3-0.6 mol / L.

3. The low-temperature aqueous electrolyte based on the double-coordination structure for anchoring I + ions, characterized in that The zinc salt is zinc perchlorate.

4. The low-temperature aqueous electrolyte based on double coordination structure for anchoring I + ions, characterized in that The electrolyte additive is trimethylamine hydrochloride.

5. The low-temperature aqueous electrolyte based on a double coordination structure for anchoring I + ions, characterized in that The electrolyte additive is trimethylamine hydrochloride and / or triethylamine hydrochloride.

6. The low-temperature aqueous electrolyte based on a dual coordination structure for anchoring I + ions, characterized in that The use temperature of the low-temperature aqueous electrolyte is ≥ -50 °C.

7. The low-temperature aqueous electrolyte based on the double coordination structure for anchoring I + ions, characterized in that The use temperature of the low-temperature aqueous electrolyte is ≥ -60 °C.

8. A low-temperature four-electron aqueous zinc-iodine battery, characterized in that, The low-temperature four-electron aqueous zinc-iodine battery includes the low-temperature aqueous electrolyte based on the double coordination structure for anchoring I + ions as claimed in any one of claims 1-7.

9. The low-temperature four-electron aqueous zinc-iodine battery according to claim 8, wherein, The low-temperature four-electron aqueous zinc-iodine battery satisfies at least one of the following conditions: The positive electrode material is a porous carbon material loaded with iodine; The negative electrode material is zinc foil or other metal foil electroplated with a certain capacity of zinc; The separator used in the low-temperature four-electron aqueous zinc-iodine battery is glass fiber.

10. The low-temperature four-electron aqueous zinc-iodine battery according to claim 9, wherein The porous carbon material includes at least one of activated carbon, carbon felt and carbon fiber; The other metal foil includes at least one of copper foil and titanium foil.

Images