Interface corrosion resistant aqueous electrolyte and battery application thereof

Abstract

The invention discloses an interface corrosion resistant aqueous electrolyte and a battery application thereof. The aqueous electrolyte comprises a zwitterionic additive; the zwitterionic additive comprises an imidazolium cation part and a sulfonate anion part; wherein a 1-site N atom in imidazolium is connected with a sulfonate radical through a C1-6 saturated alkyl carbon chain, and a 3-site N atom in imidazolium is connected with a C2-4 unsaturated alkyl carbon chain or a C1-4 saturated alkyl carbon chain. The aqueous electrolyte can effectively relieve the interface corrosion problem of the aqueous battery, so that the cycle stability of the negative electrode is improved, and the preparation of the long-cycle aqueous battery is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to an aqueous electrolyte resistant to interface corrosion and battery applications thereof. Background Art

[0002] Aqueous batteries are considered to have broad application prospects in the field of large-scale energy storage due to their high specific capacity and high safety.

[0003] However, in traditional aqueous electrolytes, water molecules have serious chemical and electrochemical corrosion on the negative electrode: the complete hydrogen bond network of water molecules in the electrode / electrolyte interface is conducive to H + It conducts electricity between water molecules through the Grothes mechanism, capturing electrons lost during the stripping process of the negative electrode metal (such as zinc metal), thereby generating a serious corrosion hydrogen evolution side reaction. In addition, the free anions with high polarity in the electrolyte adsorbed on the interface will increase the density of interfacial water molecules. At the same time, the anions that enter the solvation sheath will be brought to the negative electrode surface during the deposition process, thereby further enhancing its interfacial corrosion. Due to the differences in the surface state of the negative electrode caused by corrosion, metal ions are more inclined to nucleate at low interfacial energy during the deposition process, and quickly deposit and grow into dendrites at the nucleation site, further piercing the diaphragm and causing the battery to short-circuit, thereby seriously damaging the battery's cycle performance and coulombic efficiency.

[0004] Therefore, developing a new aqueous electrolyte that can inhibit the adsorption of free anions and / or reduce the anions in the solvation sheath is of great significance to improving the interfacial corrosion problem and promoting the application of aqueous batteries in the field of large-scale energy storage. Summary of the Invention

[0005] The present invention aims to address at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a class of aqueous electrolytes that are resistant to interfacial corrosion, which can effectively alleviate the interfacial corrosion problem of aqueous batteries, thereby improving the cycle stability of the negative electrode and enabling the preparation of long-cycle aqueous batteries.

[0006] The invention also provides a method for preparing the aqueous electrolyte.

[0007] The present invention also proposes an application of an aqueous electrolyte in an aqueous battery.

[0008] The present invention also provides an aqueous battery.

[0009] The invention also provides an electrical product.

[0010] According to one aspect of the present invention, an aqueous electrolyte is proposed, comprising a zwitterionic additive; the zwitterionic additive comprises an imidazolium cation portion and a sulfonate anion portion; wherein the nitrogen atom at position 1 of the imidazolium is connected to the sulfonate group via a C1-6 saturated alkyl carbon chain, and the nitrogen atom at position 3 is connected to a C2-4 unsaturated alkyl carbon chain or a C1-4 saturated alkyl carbon chain.

[0011] According to some embodiments of the present invention, the zwitterionic additive used in the present invention can prevent free anions from approaching the negative electrode surface. The cationic portion of the zwitterionic additive has a metal-loving negative electrode (e.g., zinc) property, and the zwitterionic additive can be adsorbed on the negative electrode surface through the cationic portion, while the anionic portion repels the free anions. At the same time, the zwitterionic additive in the interface can break the interfacial hydrogen bond network, inhibiting H + transfer.

[0012] In some preferred embodiments of the present invention, in the zwitterionic additive, the 3-position nitrogen atom of the imidazolium is connected to a C2-4 unsaturated alkyl carbon chain.

[0013] According to some preferred embodiments of the present invention, when the imidazole group in the zwitterionic additive is connected with an unsaturated alkyl carbon chain, the unsaturated alkyl carbon chain can also undergo polymerization reaction at the interface to form an SEI film, thereby further reducing the contact between the electrode and active water molecules and improving corrosion resistance.

[0014] In some embodiments of the present invention, the zwitterionic additive is selected from at least one of 1-propylsulfonic acid-3-vinyl imidazolium inner salt (PSO3VIm), 1-butylsulfonic acid-3-methylimidazolium inner salt (BSO3MIm) and 1-propylsulfonic acid-3-methylimidazolium inner salt (PSO3MIm); preferably 1-propylsulfonic acid-3-vinyl imidazolium inner salt.

[0015] In some embodiments of the present invention, the aqueous electrolyte further includes an electrolyte and a solvent.

[0016] In some embodiments of the present invention, the electrolyte comprises a soluble zinc salt.

[0017] In some embodiments of the present invention, the zinc salt is selected from at least one of zinc sulfate (ZnSO4), zinc perchlorate (Zn(ClO4)2), zinc nitrate (Zn(NO3)2), zinc chloride (ZnCl2) and zinc acetate ((CH3COO)2Zn).

[0018] In some preferred embodiments of the present invention, the zinc salt is selected from at least one of ZnSO4, Zn(ClO4)2 and Zn(NO3)2.

[0019] In some embodiments of the present invention, the solvent includes an organic solvent and water.

[0020] In some embodiments of the present invention, the organic solvent is an organic co-solvent selected from at least one of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), ethylene glycol (EG), N-methylpyrrolidone (NMP), triethyl phosphate (TEP), glycerol (TG), acetonitrile (ACN) and propylene carbonate (PC).

[0021] The organic cosolvent provided by the present invention has a high donor number, which can replace the anions in the chemical sheath and further inhibit the Zn 2+ The anions in the solvation sheath follow the Zn 2+ The present invention utilizes a zwitterionic additive and an organic co-solvent to provide a multi-component aqueous electrolyte. The organic co-solvent can synergistically act with the zwitterionic additive to further inhibit interfacial corrosion caused by highly corrosive anions, thereby improving the corrosion resistance of the battery.

[0022] In some preferred embodiments of the present invention, the organic solvent is selected from at least one of DMSO, DMF, NMP, TEP and ACN.

[0023] In some embodiments of the present invention, the water comprises deionized water and / or purified water.

[0024] In some embodiments of the present invention, the concentration of the electrolyte is 1-3 mol / L, for example, about 1.5 mol / L, about 2 mol / L, or about 2.5 mol / L.

[0025] In some embodiments of the present invention, the concentration of the zwitterionic additive is 0.1-0.8 mol / L, preferably 0.2-0.6 mol / L, such as about 0.3 mol / L, about 0.4 mol / L or about 0.5 mol / L.

[0026] In some embodiments of the present invention, the molar ratio of the electrolyte to the zwitterionic additive is 30:1-5:4. For example, the molar ratio of the electrolyte to the zwitterionic additive is 20:1-5:4 or 10:1-5:4. Specifically, the molar ratio of the electrolyte to the zwitterionic additive can be about 25:1, about 20:1, about 15:1, about 10:1, about 5:1 or about 2:1.

[0027] In some embodiments of the present invention, the mass ratio of the organic solvent to water is 4:1-1:4. For example, the mass ratio of the organic solvent to water can be about 3:1, about 2:1, about 1:1, about 1:2, or about 1:3. Preferably, the mass ratio of the organic solvent to water is 2:1-1:2.

[0028] According to another aspect of the present invention, a method for preparing the aqueous electrolyte is proposed, comprising the following steps: dissolving a zwitterionic additive and an electrolyte in a solvent to obtain the aqueous electrolyte.

[0029] According to some embodiments of the present invention, the preparation method of the present invention is simple, the raw materials are widely available, and the cost is low, which can effectively reduce the cost of battery production.

[0030] In some embodiments of the present invention, an organic solvent and water are mixed to obtain a mixed solvent, and then the zwitterion additive and the electrolyte are dissolved in the mixed solvent to obtain the electrolyte.

[0031] According to another aspect of the present invention, a use of an aqueous electrolyte in an aqueous battery is provided.

[0032] According to some embodiments of the present invention, when the aqueous electrolyte of the present invention is used in an aqueous battery, it can effectively alleviate the water molecule density at the negative electrode interface and alleviate interface corrosion, thereby improving the negative electrode cycle stability and realizing the preparation of a long-cycle aqueous battery.

[0033] According to yet another aspect of the present invention, an aqueous battery is provided, comprising the aqueous electrolyte described above or the aqueous electrolyte prepared by the above preparation method.

[0034] According to some embodiments of the present invention, a zinc symmetric battery assembled using an aqueous electrolyte modified with the zwitterionic additive of the present invention has a current density of 1 mA cm -2 , cut-off capacity of 1 mAh cm -2 Under the conditions of , it can stably cycle for more than 950 hours, and even stably cycle for 1255 hours.

[0035] According to some embodiments of the present invention, the zinc-copper half-cell assembled using the aqueous electrolyte modified by the zwitterionic additive of the present invention has a current density of 1 mA cm -2 , cut-off capacity of 1 mAh cm -2 Under the conditions of , the coulombic efficiency after 500 cycles can be maintained above 97.5%, or even above 98.0%.

[0036] In some embodiments of the present invention, the aqueous battery includes an aqueous zinc-based battery, specifically a zinc symmetric battery, a zinc-copper half-cell, an aqueous zinc-iodine full battery, and an aqueous zinc-ion full battery.

[0037] In some embodiments of the present invention, the aqueous battery further comprises a positive electrode, a negative electrode, and a separator.

[0038] In some embodiments of the present invention, the separator comprises a glass fiber separator.

[0039] In some embodiments of the present invention, the negative electrode comprises zinc foil.

[0040] In some embodiments of the present invention, the step of preparing the positive electrode includes: preparing a positive electrode active material, a conductive agent, and a binder into a slurry, and then coating the slurry onto a positive electrode current collector to form a positive electrode.

[0041] In some embodiments of the present invention, the positive electrode active material includes at least one of iodine-loaded activated carbon, vanadium trioxide (V2O3), vanadium dioxide (VO2), vanadium heptoxide (V3O7), vanadium pentoxide (V2O5) and ferricyanide (Fe4[Fe(CN)6]3).

[0042] In some embodiments of the present invention, the conductive agent is selected from at least one of conductive carbon black, acetylene black, graphene, carbon nanotubes, and carbon nanofibers.

[0043] In some embodiments of the present invention, the binder is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, carboxymethyl cellulose, polyvinyl alcohol, sodium alginate, polyurethane and polyvinylidene fluoride.

[0044] In some embodiments of the present invention, in the preparation materials of the positive electrode, the mass proportion of the positive electrode active material is 70% to 90%, the mass proportion of the conductive agent is 5% to 20%, and the mass proportion of the binder is 5% to 10%.

[0045] In some embodiments of the present invention, the positive electrode current collector is selected from at least one of carbon paper, titanium foil and stainless steel mesh.

[0046] In some embodiments of the present invention, the aqueous zinc-iodine full battery includes a positive electrode, a negative electrode, a separator and the above-mentioned aqueous electrolyte.

[0047] Specifically, the positive electrode is prepared by the following steps: activated carbon loaded with elemental iodine, a conductive agent and a binder are prepared into a slurry, which is then coated on a positive electrode current collector to form the positive electrode of an aqueous zinc-iodine full battery.

[0048] Furthermore, the method of loading elemental iodine includes a solution adsorption method; wherein the iodine loading ratio (the mass ratio of elemental iodine to the total amount of elemental iodine and activated carbon) is 10-50%, for example, about 15%, about 20%, about 30% or about 40%, preferably about 25%.

[0049] In some embodiments of the present invention, the aqueous zinc ion full battery includes a positive electrode, a negative electrode, a separator and the above-mentioned aqueous electrolyte.

[0050] Specifically, the positive electrode is prepared by the following steps: the positive electrode active material is prepared into a slurry with a conductive agent (such as conductive carbon black) and a binder (such as polyvinylidene fluoride), and then coated on a positive electrode current collector (such as carbon paper) to form the positive electrode of the aqueous zinc ion full battery.

[0051] In some preferred embodiments of the present invention, in the aqueous zinc ion full battery, the positive electrode active material includes at least one of V2O3, VO2, V3O7, V2O5 and Fe4[Fe(CN)6]3, preferably V2O3.

[0052] According to some embodiments of the present invention, the zinc symmetric battery assembled by the multi-component aqueous electrolyte of the present invention (using the synergistic effect of zwitterionic additives and organic co-solvents) at a current density of 1 mA cm -2 , cut-off capacity of 1 mAh cm -2 Under certain conditions, it can circulate stably for more than 3000 hours, or even more than 3500 hours.

[0053] According to some embodiments of the present invention, the zinc-copper half-cell assembled with the multi-component aqueous electrolyte of the present invention (using the synergistic effect of zwitterionic additives and organic co-solvents) at a current density of 1 mA cm -2 , cut-off capacity of 1 mAh cm -2 Under the conditions of , the coulombic efficiency after 500 cycles can be maintained above 99.0%, or even above 99.5%.

[0054] According to some embodiments of the present invention, the aqueous zinc-iodine full battery assembled by the multi-component aqueous electrolyte of the present invention (using the synergistic effect of zwitterionic additives and organic co-solvents) is -1 Under the conditions of 2000 cycles, the capacity retention rate can reach more than 70%, or even more than 75%.

[0055] According to another aspect of the present invention, an electrical product is provided, comprising the aqueous battery described above.

[0056] In some embodiments of the present invention, the electrical products include but are not limited to mobile phones, computers, electric cars and other devices.

[0057] The present invention has the following beneficial effects:

[0058] (1) In the aqueous electrolyte of the present invention, the zwitterionic additive can be adsorbed on the electrode surface, expelling the highly corrosive free anions from the electrode / electrolyte interface layer, while breaking the hydrogen bond network of water molecules in the interface layer, inhibiting H +Transfer between water molecules. Among them, the zwitterionic additive with an unsaturated alkyl carbon chain on the imidazole group can also undergo polymerization reaction at the interface to form an SEI film, further reducing the contact between the electrode and active water molecules. In addition, in the multi-component aqueous electrolyte containing zwitterionic additives and organic co-solvents of the present invention, the organic co-solvent can replace anions to enter the Zn 2+ The solvation sheath, while promoting the interfacial desolvation kinetics, synergistically inhibits the interfacial corrosion caused by anions with the zwitterionic additive, thereby improving the corrosion resistance of the battery.

[0059] (2) In the aqueous electrolyte of the present invention, the zwitterionic additive can react with I3 - Combined, thereby inhibiting the disproportionation reaction at the iodine positive electrode.

[0060] (3) The aqueous electrolyte of the present invention has the characteristics of wide source of raw materials, low cost, simple electrolyte modification design, etc., which can effectively reduce the cost of the battery.

[0061] (4) Compared with traditional electrolytes, the multi-component aqueous electrolyte of the present invention containing zwitterionic additives and organic co-solvents can effectively enhance the cycle stability of the negative electrode and the iodine positive electrode. When used in a zinc symmetrical battery, it can stably cycle for 3655 hours; when used in a zinc-copper half-cell, the coulombic efficiency can reach 99.6% after 200 cycles; when used in an aqueous zinc-iodine full battery, the coulombic efficiency can reach 99.6% at 0.2Ag. -1 The capacity retention rate can reach 75.4% after 2000 cycles at a current density of 1.54 Å. Therefore, the present invention provides an important approach for preparing long-cycle aqueous battery electrolytes. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0063] Figure 1 Raman spectra of ZS, ZSP and ZSPD electrolytes prepared in Examples 1-3;

[0064] Figure 2 Cycling performance diagram of zinc symmetric battery using ZS and ZSPD electrolytes prepared in Example 1-2;

[0065] Figure 3 Coulombic efficiency diagram of zinc-copper half-cell using ZS and ZSPD electrolytes prepared in Example 1-2;

[0066] Figure 4 Cycling performance diagram of zinc symmetrical battery after zinc foil is immersed in ZS and ZSPD electrolyte prepared in Example 1-2 for 24h;

[0067] Figure 5.Cycling performance diagram of aqueous zinc-iodine full batteries using ZS and ZSPD electrolytes prepared in Examples 57-58. DETAILED DESCRIPTION

[0068] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0069] Unless otherwise specified, the experimental methods used in the examples are conventional methods. The materials and reagents used are commercially available unless otherwise specified. Unless otherwise specified, the same parameter values ​​are the same across the examples. The examples described below are illustrative and intended only to illustrate the present invention and are not to be construed as limiting the present invention.

[0070] In the description of the present invention, reference to the term "some embodiments" or the like indicates that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0071] Numerical data are presented herein in a range format. The term "about" as used herein is known to those skilled in the art. Alternatively, the term "about" includes ±2%, ±1%, ±0.5%, ±0.2% of the stated value. It should be understood that this range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the values ​​explicitly listed as range limits, but also all individual values ​​or subranges encompassed within the range, as if each value and subrange were explicitly recited.

[0072] As used herein, the term "C1-n saturated alkyl carbon chain" refers to a linear or branched saturated alkyl carbon chain having 1 to n carbon atoms, for example, 1, 2, 3, 4, 5 or 6 carbon atoms. Non-limiting examples of saturated alkyl carbon chains include methyl, ethyl, propyl, butyl, pentyl and hexyl.

[0073] As used herein, the term "C2-4 unsaturated alkyl carbon chain" refers to a carbon chain containing at least one unsaturated carbon-carbon sp 2a double bond, a linear or branched unsaturated alkyl carbon chain having 2 to 4 carbon atoms. Specifically, the number of carbon atoms can be 1, 2, 3 or 4. Non-limiting examples of the unsaturated alkyl carbon chain include: vinyl, propenyl, allyl, 1-butadienyl and 2-butadienyl.

[0074] As used herein, "imidazolium" refers to a cation with a single positive charge formed when the imidazole ring loses an electron or undergoes alkylation / protonation.

[0075] Example 1

[0076] This example prepares an aqueous multi-component electrolyte and a battery. The specific process is as follows:

[0077] Preparation of aqueous multi-component electrolyte:

[0078] At room temperature, deionized water and DMSO were mixed in a mass ratio of 1:1 and stirred for 10 min to obtain a mixed solvent for later use.

[0079] ZnSO4 and PSO3Vim were mixed in a molar ratio of 5:1, and then an appropriate amount of mixed solvent was added and stirred to obtain a solution containing 2M ZnSO4 + 0.4M PSO3Vim ("M" represents mol / L), which is the ZSPD electrolyte.

[0080] Assemble a zinc symmetrical battery: Carefully polish the zinc foil and place it on the positive and negative electrodes respectively. Use glass fiber as a separator and ZSPD as the electrolyte to assemble it into a CR2032 button battery.

[0081] Assemble zinc-copper half-cells: Use copper foil as the positive electrode, zinc foil as the negative electrode, glass fiber as the separator, and ZSPD as the electrolyte to assemble into CR2032 button batteries.

[0082] Example 2

[0083] This embodiment prepares an aqueous electrolyte and a battery, and the specific process is as follows:

[0084] Preparation of aqueous electrolyte:

[0085] At room temperature, ZnSO4 is dissolved in an appropriate amount of deionized water and stirred to obtain a solution containing 2M ZnSO4, which is the ZS electrolyte.

[0086] The battery was prepared as described in Example 1.

[0087] Example 3

[0088] This embodiment prepares an aqueous electrolyte and a battery, and the specific process is as follows:

[0089] Preparation of aqueous electrolyte:

[0090] At room temperature, ZnSO4 and PSO3Vim were mixed in a molar ratio of 5:1, and then an appropriate amount of deionized water was added and stirred to obtain a solution containing 2M ZnSO4+0.4M PSO3Vim, which was the ZSP electrolyte.

[0091] The battery was prepared as described in Example 1.

[0092] Example 4

[0093] This embodiment prepares an aqueous electrolyte and a battery, and the specific process is as follows:

[0094] Preparation of aqueous electrolyte:

[0095] At room temperature, deionized water and DMSO were mixed in a mass ratio of 1:1 and stirred for 10 min to obtain a mixed solvent for later use.

[0096] Dissolve ZnSO4 in an appropriate amount of mixed solvent and stir to obtain a solution containing 2M ZnSO4, which is the ZSD electrolyte.

[0097] The battery was prepared as described in Example 1.

[0098] The following is an explanation with reference to the accompanying drawings:

[0099] like Figure 1 As shown in the figure, ZSPD electrolyte has a better performance than ZS electrolyte and ZSP electrolyte at a wavelength of 675.1 cm -1 、711cm -1 、949.2cm -1 、1012.5cm -1 There is an obvious Raman peak at 980cm, which corresponds to the characteristic peak of DMSO. -1 Around, the three electrolytes have obvious Raman peaks, corresponding to SO4 2- However, the SO4 2- The vibration peaks are red-shifted compared with those in ZS electrolyte and ZSP electrolyte, which indicates that SO4 2- More in the state of separated ion pairs, the surface DMSO solvent replaces SO4 2- Enter the zinc ion solvation sheath. On the one hand, this shows that DMSO co-solvent can replace the water in the solvation sheath and reduce the activity of water molecules; on the other hand, DMSO co-solvent replaces SO4 2- Entering the solvation sheath is also beneficial to the desolvation kinetics of zinc ions at the interface, thereby helping to inhibit interfacial corrosion.

[0100] Figure 2It shows that compared with ZS electrolyte, the cycling performance of zinc symmetric battery with ZSPD electrolyte is significantly improved. -2 At a current density of 1 mAh cm -2 It can stably cycle for more than 2000 hours at the cut-off capacity. Figure 3 The results show that the Zn-Cu half-cell of ZSPD electrolyte has higher coulombic efficiency at a discharge current density of 1 mA cm -2 , discharge cut-off capacity is 1mAhcm -2 , when the charge cut-off voltage is 0.6V, the coulombic efficiency remains above 99.5% after 500 cycles. Figure 4 As shown in the figure, the first cycle curve of the zinc foil after immersion in ZS electrolyte for 24 hours is unstable, while the zinc foil after immersion in ZSPD electrolyte for 24 hours can still maintain a stable charge and discharge curve, which indicates that the zwitterionic additive and organic co-solvent can significantly inhibit interfacial corrosion.

[0101] Examples 5-56

[0102] The preparation process of Examples 5-6 is the same as that of Example 2, and the only difference is the content of the electrolyte components; the preparation process of Examples 7-29 is the same as that of Example 3, and the only difference is the electrolyte components and / or contents; the preparation process of Examples 30-56 is the same as that of Example 1, and the only difference is the electrolyte components and / or contents; refer to Table 1 for details. Among them, 2MZnSO4 electrolyte is recorded as ZS, 2M ZnSO4+0.4M PSO3VIm electrolyte is recorded as ZSP, 2MZnSO4+DMSO electrolyte is recorded as ZSD, and 2M ZnSO4+0.4M PSO3Vim+DMSO-1:1 electrolyte is recorded as ZSPD (the number after the organic co-solvent represents the mass ratio between the organic co-solvent and water). 1-propyl pyridinium sulfonate is represented by PSO3Py. Among them, the current density of the zinc symmetric battery test is 1mA cm -2 , with a cut-off capacity of 1 mAh cm -2 ; The discharge current density of the zinc-copper half-cell test is 1 mA cm -2 , the discharge cut-off capacity is 1 mAh cm -2 , the charging cut-off voltage is 0.6V.

[0103] Table 1: Performance comparison of zinc symmetric cells and zinc-copper half-cells using different electrolytes

[0104]

[0105]

[0106]

[0107]

[0108] As shown in Table 1, after adding zwitterionic additives, the zinc symmetric battery cycle performance of the electrolyte and the coulombic efficiency of the zinc-copper half-cell are significantly improved. Among them, the zwitterionic additives 1-propylsulfonic acid-3-vinyl imidazole inner salt (PSO3VIm), 1-butylsulfonic acid-3-methylimidazolium inner salt (BSO3MIm) and 1-propylsulfonic acid-3-methylimidazolium inner salt (PSO3MIm) all show better performance than 1-propylsulfonic acid pyridine inner salt (PSO3Py). This may be because there are two N on the imidazole ring as adsorption sites, which makes the imidazole inner salt easier to adsorb on the negative electrode surface than the pyridine inner salt. Among them, the PSO3VIm additive has the best effect, which may be because the PSO3VIm additive can not only be adsorbed on the negative electrode surface to avoid SO4 2- The unsaturated vinyl groups attached to the imidazole groups can also undergo in-situ polymerization to form a SEI film, further preventing contact between the negative electrode and water molecules. Among the electrolytes with various concentrations of PSO3VIm additives, the ZSP electrolyte has the best electrolyte and additive concentrations.

[0109] After adding the organic co-solvent, the performance of the zinc symmetrical battery and the zinc-copper half-cell was further improved, especially the cycle performance of the zinc symmetrical battery was greatly improved, which shows that the zwitterionic additive of the present invention and the organic co-solvent can play a synergistic role, better inhibit interfacial corrosion, and thus significantly improve the cycle stability of the battery. Among them, PSO3VIm, BSO3MIm and PSO3Mim, after acting together with the organic co-solvent, all showed significantly improved cycle performance compared with a single additive or organic co-solvent; while after acting together with the organic co-solvent, the cycle performance of PSO3Py was worse than that of a single organic co-solvent, indicating that the two did not fully play a synergistic role, which may be because PSO3Py replaced part of the organic co-solvent and entered the Zn 2+ Solvated structure, which increases the desolvation barrier.

[0110] Among various organic co-solvents, DMSO, DMP, TEP, NMP and ACNA showed better performance than EG, PC and TG, which may be because they can reduce the density of interfacial water molecules. Among them, DMSO has the best performance, which may be because DMSO has a larger polarity and can replace more SO4 2- Entering the solvation structure, it reduces the active solvated water molecules while accelerating the desolvation, thereby inhibiting corrosion and hydrogen evolution side reactions. Among various electrolytes, ZnSO4, Zn(ClO4)2 and Zn(NO3)2 show better performance than ZnCl2, which may be because Cl - It is easily oxidized. Among them, ZnSO4 has the best performance.

[0111] Example 57

[0112] This example prepares an aqueous zinc-iodine full battery, and the specific process is as follows:

[0113] Assemble an aqueous zinc-iodine full battery: Add 0.3g of iodine and 0.9g of activated carbon (25% iodine loading ratio by mass) to 300ml of deionized water and stir for 5 hours, then dry at 50°C for 6 hours to obtain iodine-loaded activated carbon. The iodine-loaded activated carbon is mixed with conductive carbon black and polyvinylidene fluoride in a ratio of 7:2:1, ground for 30 minutes, and then N-methylpyrrolidone is added to form a slurry, which is then evenly coated on carbon paper to make a positive electrode. Use this positive electrode, ZSPD as the electrolyte, zinc foil as the negative electrode, and glass fiber as the separator to assemble a CR2032 button battery.

[0114] Example 58

[0115] The preparation process of Example 58 is the same as that of Example 57, except that ZS is used as the electrolyte.

[0116] Figure 5 It shows that the aqueous zinc-iodine battery using ZSPD as the electrolyte has better cycle performance. -1 After 2000 cycles at a current density of 1000, the capacity retention rate of the aqueous zinc-iodine battery using ZS as the electrolyte was 75.4%. -1 The capacity retention rate was only 67.3% after 1000 cycles at a current density of , and the capacity became 0 after 1284 cycles.

[0117] Examples 59-66

[0118] The preparation process of Examples 59-66 is the same as that of Example 57, except that the iodine loading ratio (mass ratio) is different, as shown in Table 2. The voltage range of the test is 0.6-1.6 V, and the current density is 0.2 Ag -1 .

[0119] Table 2: Performance comparison of aqueous zinc-iodine batteries using different iodine loading ratios

[0120]

[0121]

[0122] It can be seen from Table 2 that when the iodine loading ratio is about 25%, the overall performance of the battery is the best.

[0123] Examples 67-70

[0124] The preparation process of Examples 67-70 is the same as that of Example 57, and the only difference is the type of conductive agent, as shown in Table 3. The voltage range of the test is 0.6-1.6V, and the current density is 0.2Ag -1 .

[0125] Table 3: Performance comparison of aqueous zinc-iodine batteries using different conductive agents

[0126]

[0127] As can be seen from Table 3, when the aqueous zinc-iodine battery uses conductive carbon black (Super-P) as the conductive agent, the overall performance of the battery is the best.

[0128] Examples 71-76

[0129] The preparation process of Examples 71-76 is the same as that of Example 57, and the only difference is the type of binder, as shown in Table 4. The voltage range of the test is 0.6-1.6V, and the current density is 0.2Ag. -1 .

[0130] Table 4: Performance comparison of aqueous zinc-iodine batteries using different binders

[0131]

[0132]

[0133] As can be seen from Table 4, the specific capacity of aqueous zinc-iodine batteries is not significantly affected by the type of binder, but the cycling performance is significantly affected. Specifically, the cycling performance is poor when the binder is carboxylated styrene-butadiene latex, while the cycling performance is best when the binder is polyvinylidene fluoride.

[0134] Examples 77-79

[0135] The preparation process of Examples 77-79 is the same as that of Example 57, and the only difference is the type of positive electrode current collector, as shown in Table 5. The voltage range of the test is 0.6-1.6V, and the current density is 0.2Ag -1 .

[0136] Table 5: Performance comparison of aqueous zinc-iodine batteries using different cathode current collectors

[0137]

[0138] It can be seen from Table 5 that the comprehensive performance of aqueous zinc-iodine batteries is not greatly affected by the type of positive electrode current collector, among which the comprehensive performance is the best when the positive electrode current collector is carbon paper.

[0139] Example 80

[0140] This example prepares an aqueous zinc ion full battery, and the specific process is as follows:

[0141] To assemble an aqueous zinc-ion full battery, V₂O₃ was mixed with conductive carbon black and polyvinylidene fluoride in a ratio of 7:2:1. After grinding for 30 minutes, N-methylpyrrolidone was added to form a slurry, which was then evenly coated on carbon paper to form the positive electrode. This positive electrode, along with ZSPD as the electrolyte, zinc foil as the negative electrode, and glass fiber as the separator, was assembled into a CR2032 button cell.

[0142] Examples 81-89

[0143] The preparation process of Examples 81-89 is the same as that of Example 80, the only difference being the types of positive electrode active materials and electrolytes, as shown in Table 6. The test current density is 0.2Ag -1 .

[0144] Table 6: Performance comparison of aqueous zinc-ion batteries using different cathode active materials and electrolytes

[0145]

[0146] It can be seen from Table 6 that in aqueous zinc ion full batteries, the specific capacity and cycle performance of ZSPD electrolyte are significantly higher than those of ZS electrolyte.

[0147] In summary, in the aqueous electrolyte of the present invention, the zwitterionic additive can prevent free anions from approaching the electrode / electrolyte interface layer, while breaking the hydrogen bond network of water molecules in the interface layer, inhibiting H + Transfer between water molecules; organic cosolvents can replace anions to enter Zn 2+ The solvation sheath, while promoting the interfacial desolvation kinetics, synergistically inhibits the interfacial corrosion caused by anions with the zwitterionic additives, thereby effectively alleviating the interfacial corrosion problem of aqueous batteries, improving the cycle stability of the negative electrode, and realizing the preparation of long-cycle aqueous batteries.

[0148] While the embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to the embodiments described above. Various modifications may be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof may be combined with one another unless there is a conflict.

Claims

1. An aqueous electrolyte, characterized in that The invention comprises a zwitterionic additive, wherein the zwitterionic additive comprises an imidazolium cation portion and a sulfonate anion portion, wherein the nitrogen atom at position 1 in the imidazolium is connected to the sulfonate group via a C1-6 saturated alkyl carbon chain, and the nitrogen atom at position 3 is connected to a C2-4 unsaturated alkyl carbon chain or a C1-4 saturated alkyl carbon chain.

2. The aqueous electrolyte according to claim 1, characterized in that The zwitterionic additive is at least one selected from 1-propylsulfonic acid-3-vinyl imidazolium inner salt, 1-butylsulfonic acid-3-methylimidazolium inner salt and 1-propylsulfonic acid-3-methylimidazolium inner salt.

3. The aqueous electrolyte according to claim 1 or 2, characterized in that Also includes electrolytes and solvents.

4. The aqueous electrolyte according to claim 3, characterized in that The electrolyte includes a zinc salt; the zinc salt includes at least one selected from the group consisting of ZnSO4, Zn(ClO4)2, Zn(NO3)2, ZnCl2 and (CH3COO)2Zn; The solvent includes an organic solvent and water; the organic solvent is selected from at least one of dimethyl sulfoxide, N,N-dimethylformamide, ethylene glycol, N-methylpyrrolidone, triethyl phosphate, acetonitrile and propylene carbonate; The concentration of the electrolyte is 1-3 mol / L; The molar ratio of the electrolyte to the zwitterionic additive is 30:1-5:4; The mass ratio of the organic solvent to water is 4:1-1:

4.

5. A method for preparing an aqueous electrolyte according to claim 3, characterized in that: The method comprises the following steps: dissolving a zwitterion additive and an electrolyte in a solvent to obtain the aqueous electrolyte.

6. Use of the aqueous electrolyte according to any one of claims 1 to 4 in an aqueous battery.

7. An aqueous battery, characterized in that: The invention comprises the aqueous electrolyte according to any one of claims 1 to 4 or the aqueous electrolyte prepared by the preparation method according to claim 5.

8. The aqueous battery according to claim 7, wherein: Including zinc symmetric batteries, zinc-copper half-cells, aqueous zinc-iodine full batteries and aqueous zinc-ion full batteries.

9. The aqueous battery according to claim 7 or 8, characterized in that The aqueous battery further comprises a positive electrode, a negative electrode and a separator; The diaphragm includes a glass fiber diaphragm; The negative electrode includes zinc foil; The preparation steps of the positive electrode include: preparing a positive electrode active material, a conductive agent and a binder into a slurry, and then coating the slurry on a positive electrode current collector to form the positive electrode; The positive electrode active material is selected from at least one of iodine-loaded activated carbon, vanadium trioxide, vanadium dioxide, vanadium heptoxide, vanadium pentoxide and ferric ferrocyanide; The conductive agent is selected from at least one of conductive carbon black, acetylene black, graphene, carbon nanotubes and carbon nanofibers; The binder is selected from at least one of polyvinyl difluoride, polytetrafluoroethylene, carboxymethyl cellulose, polyvinyl alcohol, sodium alginate, polyurethane and polyvinylidene fluoride; The positive electrode current collector is selected from at least one of carbon paper, titanium foil and stainless steel mesh.

10. An electrical product, characterized in that: An aqueous battery comprising the aqueous battery according to any one of claims 7 to 9.

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