Preparation method and application of zinc ion battery additive based on peptide bond interface regulation and control

Abstract

The invention relates to an aqueous zinc ion battery electrolyte additive, an electrolyte and preparation and application thereof, and belongs to the technical field of zinc ion batteries. The additive is a peptide bond-containing compound consisting of amino acid or small molecule peptide; the amino acid residue in the peptide bond compound is one or more of glycine (Gly), alanine (Ala), serine (Ser), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), histidine (His) and arginine (Arg). And the electrolyte comprises 0.02 mol / L to 0.2 mol / L of the additive. And adding the additive into a mixed solvent consisting of zinc salt and an aqueous solvent, uniformly mixing, and standing to obtain the electrolyte. C = O (hydrogen bond acceptor) and N-H (hydrogen bond donor) of peptide bonds in the additive are alternately adsorbed on the surface of the zinc negative electrode to form a compact hydrogen bond network, so that direct contact between electrolyte and zinc is physically blocked, and side reaction is inhibited.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a zinc ion battery additive based on a peptide bond interface regulation and application thereof, and belongs to the technical field of zinc ion batteries. BACKGROUND

[0002] Under the background of profound changes in the global energy pattern, energy security and environmental protection have become the core issues of development for all countries. The research and development of new generation energy storage technology has become the focus of scientific and technological competition among countries.

[0003] The current mainstream alkali metal ion battery, especially lithium ion battery, has achieved great success in the field of portable electronic devices and electric vehicles, but its inherent limitations are increasingly prominent in large-scale energy storage applications. First, the global distribution of lithium resources is extremely uneven, with about 70% of lithium reserves concentrated in the "lithium triangle" region of South America (Chile, Argentina, Bolivia). The unevenness of this resource endowment has led to sharp fluctuations in the price of lithium carbonate in recent years, seriously affecting the stable development of the industry chain. Second, the organic electrolyte used in lithium ion batteries has the characteristics of flammability, explosion and toxicity, and the safety hidden danger is prominent. In addition, the supply shortage and price fluctuations of cobalt, nickel and other key materials have further restricted the sustainable development of lithium ion batteries.

[0004] In comparison, aqueous zinc ion batteries exhibit unique competitive advantages. The main advantages of aqueous zinc ion batteries are as follows: (1) zinc reserves are relatively abundant. Zinc is the 24th most abundant element in the earth's crust (94 mg / kg), with a global proven reserve of over 1.9 billion tons, more than 3,000 times the global proven reserve of lithium, and mature smelting technology, with a price of only 1 / 30 of the price of lithium metal. This resource advantage makes the material cost of zinc ion batteries controllable, significantly lower than that of lithium ion batteries, especially suitable for large-scale energy storage applications. (2) Zinc ion battery has intrinsic safety characteristics. The use of neutral / weak acid aqueous electrolyte system completely solves the flammable and explosive risk of organic electrolyte. Aqueous zinc ion battery can remain stable under abuse conditions such as needle puncture and extrusion. At the same time, zinc metal has significantly higher stability than alkali metals (lithium, sodium, potassium, etc.), and it is stable and non-flammable in air, and its reaction rate with water is 8 orders of magnitude lower than that of lithium, making it exhibit high safety during storage and use. This safety makes it irreplaceable in special scenarios such as residential energy storage and underground space. (3) Zinc ion battery has superior performance. The divalent nature of zinc ions gives it a mass specific capacity of 820 mAh / g, and more notably, its 5854 mAh / cm 3volume capacity of 2.8 times that of lithium metal. Moreover, aqueous electrolytes have a high ionic conductivity of 0.1 S / cm, which is one order of magnitude higher than that of organic electrolytes (<0.01 S / cm), allowing the battery to maintain a high capacity at high rates. These characteristics make them particularly suitable for high-power applications in space-constrained scenarios.(4) Zinc-ion batteries exhibit outstanding advantages in environmental friendliness, perfectly fitting the concept of green and sustainable development. The entire battery system is free of strategic metals such as cobalt and nickel, and toxic substances, and uses a near-neutral and slightly acidic aqueous electrolyte, fundamentally avoiding heavy metal pollution and environmental risks of strong acids and bases. In terms of resource recycling, the recovery rate of zinc metal can reach more than 95%, and existing mature zinc smelting facilities can be easily modified for battery recycling, greatly reducing the cost threshold of recycling system construction. Moreover, zinc is a trace element essential for the human body, and its environmental toxicity is extremely low, so even if the electrolyte leaks, it will not cause persistent ecological harm.

[0005] However, the industrial application of zinc-ion batteries is still subject to two key scientific problems:(1) First, the uncontrollable growth of zinc dendrites. During electrochemical cycling, the deposition / stripping process of zinc metal exhibits intrinsic inhomogeneity, which forms nano- or micro-sized protrusions on the electrode surface. Due to the tip-enhanced effect, the local electric field strength at these protrusions is significantly higher than that in the planar region, leading to the preferential deposition of positively charged zinc ions (Zn 2+ ) at the protrusions in subsequent cycles. This positive feedback mechanism causes the surface morphology to deteriorate, eventually forming zinc dendrites with a fractal structure. Notably, zinc metal has an extremely high Young's modulus (108 GPa), which is much higher than that of alkali metals such as lithium (5 GPa) and sodium (10 GPa), and even higher than the mechanical strength of most commercial separators. Therefore, during cycling, these rigid dendrites can easily penetrate the separator, causing internal short circuits in the battery. More seriously, due to the weak bonding force between zinc dendrites and the current collector, some dendrites will detach from the electrode surface during continuous charging and discharging, forming electrochemically inactive "dead zinc", which not only directly leads to active material loss but also exacerbates the inhomogeneity of the electrode surface, forming a vicious cycle.(2) Second, the hydrogen evolution corrosion problem on the zinc anode surface. From the perspective of electrochemical thermodynamics, the standard electrode potential of zinc (-0.76 V vs. SHE) is lower than the theoretical decomposition potential of water, which makes the hydrogen evolution reaction (HER) inevitable on the zinc anode surface in conventional neutral / weakly acidic electrolytes (such as ZnSO4 solution). This side reaction has multiple negative effects: on the one hand, the generated hydrogen gas accumulates at the electrode / electrolyte interface, leading to an increase in internal pressure of the battery, which may cause electrolyte leakage and even battery shell rupture in severe cases; on the other hand, the continuous hydrogen evolution reaction consumes water molecules in the electrolyte, changes the local electrolyte composition, and forms a pH gradient on the electrode surface. Specifically, due to the high overpotential of the hydrogen evolution reaction on the zinc anode surface, the local pH value is significantly higher than that in the bulk electrolyte, which leads to the formation of zinc hydroxide (Zn(OH)2) and zinc oxide (ZnO) on the electrode surface. These corrosion products not only increase the overpotential of the zinc deposition reaction, but also change the local zinc ion concentration, further exacerbating the inhomogeneity of the zinc anode surface.+ continuous consumption, the electrolyte near the negative electrode will gradually become alkaline (pH rises to 6-7.5), prompting Zn 2+ reacts with OH - to generate a series of insulating by-products, including zinc oxide (ZnO), zinc hydroxide (Zn(OH)2) and more complex basic zinc sulfate (such as Zn4SO4(OH)6·xH2O). These non-conductive passivation layers not only hinder the transmission of Zn 2+ , increase the interface impedance, but also cause irreversible consumption of active zinc, which accumulates with the increase of cycle number, eventually leading to rapid degradation of battery performance. SUMMARY

[0006] Therefore, in order to solve the problems of zinc dendrite growth and HER corrosion reaction in the existing zinc ion battery, the purpose of the present application is to provide a preparation method and application of a zinc ion battery additive based on peptide bond interface regulation. The use of the electrolyte additive of the present application can generate a dynamic interface shielding layer on the surface of zinc foil. The C=O (hydrogen bond acceptor) and N-H (hydrogen bond donor) of the peptide bond (-CO-NH-) alternately adsorb on the surface of the zinc negative electrode, forming a dense hydrogen bond network that physically blocks the direct contact of the electrolyte with zinc and inhibits side reactions. The polar characteristics of the peptide bond enable it to form a strong coordination with zinc metal, forming a SEI-like protective layer with a thickness of about 5-8 nm, which can effectively regulate the solvation sheath structure of Zn 2+ . The C=O lone pair electrons of the peptide bond are embedded in the Zn 2+ solvation sheath, partially replacing the active water molecules, thereby reducing the hydrogen evolution (HER) and corrosion caused by [Zn(H2O)6] 2+ hydrolysis. At the same time, the oxidation stability of the peptide bond (~1.8V vs. Zn 2+ / Zn) is higher than the water decomposition voltage (1.23V), inhibiting anode oxygen evolution (OER). This type of electrolyte additive not only regulates the uniform deposition of zinc, but also inhibits the growth of zinc dendrites, improves the cycle life of zinc ion batteries, and improves the electrochemical performance of the full battery.

[0007] To achieve the purpose of the present application, the following technical solutions are provided.

[0008] A water-based zinc ion battery electrolyte additive, the additive is a peptide bond-containing compound composed of amino acids or small molecule peptides; the amino acid residues in the peptide bond compound are one or more of glycine (Gly), alanine (Ala), serine (Ser), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), histidine (His) and arginine (Arg).

[0009] Preferably, the amino acid residue is one or more of glycine (Gly), alanine (Ala), and histidine (His).

[0010] Preferably, the peptide bond compound is one or more of dipeptide or tripeptide.

[0011] More preferably, the additive is one or more of carnosine (β-alanyl-1-methylhistidine), β-alanylhistidine (carnosine, β-Ala-His), glycylglycine (Gly-Gly), and acetylcysteine (Ac-Cys).

[0012] An aqueous zinc ion battery electrolyte, the electrolyte comprising an aqueous solvent, a zinc salt, and the electrolyte additive of the present application; the concentration of the electrolyte additive is 0.02 mol / L-0.2 mol / L.

[0013] The aqueous solvent and zinc salt are aqueous solvent and zinc salt used in the prior art aqueous zinc ion battery.

[0014] Preferably, the zinc salt is one or more of zinc sulfate (ZnSO4), zinc triflate (Zn(OTf)2), zinc chloride (ZnCl2), and zinc nitrate (Zn(NO3)2).

[0015] More preferably, the aqueous solvent is water; the zinc salt is zinc sulfate (ZnSO4), and the concentration of the zinc salt in the electrolyte is 1-3 M.

[0016] A preparation method of the electrolyte of the present application, the method steps are as follows:

[0017] (1) In the room temperature and atmospheric pressure air environment (25℃), weigh the zinc salt in a beaker, add an appropriate amount of aqueous solvent, and stir to dissolve while adding, then ultrasonic for 5min-30min to make the particles completely dissolved, to obtain a mixed solution.

[0018] (2) Add the electrolyte additive of the present application to the mixed solution, mix uniformly, and then stand for 15min-60min to obtain the electrolyte of the present application.

[0019] Preferably, in step (1), the aqueous solvent and zinc salt are mixed uniformly by magnetic stirring and ultrasonic dispersion.

[0020] Preferably, in step (2), the electrolyte additive and the mixed solution are mixed uniformly by magnetic stirring and ultrasonic dispersion.

[0021] More preferably, in steps (1) and (2), first magnetic stirring for 1h, and then ultrasonic dispersion for 1h, to make the electrolyte additive and the mixed solution mixed uniformly.

[0022] An aqueous zinc ion battery, wherein the electrolyte of the battery is the electrolyte according to the application.

[0023] Advantages

[0024] (1) The application provides a zinc ion battery electrolyte additive containing a peptide bond, which can simultaneously realize uniform deposition of zinc ions and regulation of interfacial water activity through the synergistic effect of the bifunctional groups of the peptide bond (-CO-NH-). The C=O group in the peptide bond forms a strong coordination bond with Zn 2+ , thereby regulating the ion deposition behavior; the N-H group inhibits the activity of water molecules through a hydrogen bond network. This unique molecular structure enables the additive to have the dual functions of "zincophilic-hydrophobic", thereby significantly improving the uniformity of zinc deposition and the coulombic efficiency.

[0025] (2) The peptide bond additive according to the application is in dynamic equilibrium in the electrolyte:

[0026] This equilibrium ensures the stability of the additive and also produces active groups for the construction of SEI films through moderate hydrolysis. In particular, the coordination of the peptide bond with Zn 2+ can reduce the desolvation energy barrier by about 0.12-0.18 eV, and the hydrophobic groups (such as methyl groups and benzene rings) in the molecule can effectively block water molecules from contacting the zinc surface, thereby reducing the hydrogen evolution reaction rate by more than 60%.

[0027] (3) The electrolyte provided by the application has a simple and efficient preparation process, and the peptide bond additive can be directly dissolved in a conventional zinc salt electrolyte (such as 2M ZnSO4), and a dense interfacial protective layer can be formed at a low additive amount. Through the optimized magnetic stirring-ultrasonic dispersion process, the additive can be uniformly distributed, which is suitable for large-scale production.

[0028] (4) The peptide bond electrolyte additive provided by the application significantly improves the battery performance through multiple action mechanisms: on the one hand, the polar groups (such as C=O and N-H) in the peptide bond molecule form a stable coordination structure with zinc ions, guiding the uniform deposition of zinc ions, reducing the zinc deposition overpotential, and effectively inhibiting the growth of zinc dendrites. The zinc-zinc metal symmetric battery assembled has small polarization, high full battery capacity retention rate, and the coulombic efficiency is not prone to decay, and a safe and long-acting aqueous zinc ion battery can be obtained, which is conducive to the stable improvement of the cycle life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a cycle test result graph of the Zn||Zn symmetric battery assembled by the control group and the experimental group in Test Example 1 at 1 mA cm -2 , 1 mAh cm -2 .

[0030] Figure 2 is the cycle test result graph of Zn||Zn symmetric battery assembled by the control group and the experimental group in Test Example 1 at 5 mA cm -2 , 1 mAh cm -2 under the condition of 5 mA cm

[0031] Figure 3 is the cycle test result graph of Zn||I2 full battery assembled by the control group and the experimental group respectively in Test Example 1 at 5 Ag -1 (1C = 211 mAh g -1 ) under the condition of 5 Ag. DETAILED DESCRIPTION

[0032] The application will be further described in conjunction with specific embodiments, wherein the methods are all conventional methods without special instructions, and the raw materials are all obtained from public commercial channels or prepared according to the literature without special instructions.

[0033] Example 1

[0034] A zinc ion battery electrolyte containing ananserine (β-alanyl-1-methylhistidine ANS) additive, and the preparation method is as follows:

[0035] (1) Zinc ion battery electrolyte preparation: in the environment of room temperature and normal pressure air (25℃), weigh zinc sulfate heptahydrate in a beaker, add an appropriate amount of water-based solvent, and dissolve by stirring while adding. The water-based solvent is deionized water, and the amount of ZnSO4 is ensured to make the concentration of ZnSO4 in the electrolyte prepared in this embodiment be 2 mol / L.

[0036] (2) Add ananserine (β-alanyl-1-methylhistidine ANS) to the mixed solvent, and supplement water-based solvent to reach a specific concentration. Use a magnetic stirrer for magnetic stirring for 1 h, and then use an ultrasonic disperser for ultrasonic dispersion for 1 h to achieve uniform mixing, to obtain a mixed solution. Then stand for 1 h to obtain a zinc ion battery zinc sulfate electrolyte containing an ANS additive. The water-based solvent is deionized water, the specific concentration of ANS is 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte is 2 mol / L. The preparation of the zinc ion battery electrolyte is completed.

[0037] Example 2

[0038] A zinc ion battery electrolyte containing glycylglycine additive, and the preparation method is as follows:

[0039] (1) Zinc ion battery electrolyte preparation: In the environment of room temperature and normal pressure air (25℃), take zinc sulfate heptahydrate in a beaker, add appropriate amount of water-based solvent, dissolve while stirring, then completely dissolve the particles by ultrasonic for 10 min. The water-based solvent is deionized water, and the amount of ZnSO4 ensures that the concentration of ZnSO4 in the electrolyte prepared in this example is 2 mol / L.

[0040] (2) Glycylglycine is added to the mixed solvent, and water-based solvent is supplemented to reach a specific concentration. Magnetic stirring is performed using a magnetic stirrer for 1 h, and ultrasonic dispersion is performed using an ultrasonic disperser for 1 h to achieve uniform mixing. A mixed solution is obtained. After standing for 1 h, a zinc ion battery zinc sulfate electrolyte containing glycylglycine additive is obtained. The water-based solvent is deionized water, the specific concentration of glycylglycine is 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte is 2 mol / L. The preparation of the zinc ion battery electrolyte is completed.

[0041] Example 3

[0042] A zinc ion battery electrolyte containing carnosine (β-alanylhistidine) additive is prepared by the following method:

[0043] (1) Zinc ion battery electrolyte preparation: In the environment of room temperature and normal pressure air (25℃), take zinc sulfate heptahydrate in a beaker, add appropriate amount of water-based solvent, dissolve while stirring, then completely dissolve the particles by ultrasonic for 10 min. The water-based solvent is deionized water, and the amount of ZnSO4 ensures that the concentration of ZnSO4 in the electrolyte prepared in this example is 2 mol / L.

[0044] (2) Carnosine (β-alanylhistidine) is added to the mixed solvent, and water-based solvent is supplemented to reach a specific concentration. Magnetic stirring is performed using a magnetic stirrer for 1 h, and ultrasonic dispersion is performed using an ultrasonic disperser for 1 h to achieve uniform mixing. A mixed solution is obtained. After standing for 1 h, a zinc ion battery zinc sulfate electrolyte containing carnosine additive is obtained. The water-based solvent is deionized water, the specific concentration of carnosine is 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte is 2 mol / L. The preparation of the zinc ion battery electrolyte is completed.

[0045] Example 4

[0046] A zinc ion battery electrolyte containing acetylcysteine additive is prepared by the following method:

[0047] (1) Zinc ion battery electrolyte preparation: In the environment of room temperature and normal pressure air (25℃), take the zinc sulfate heptahydrate in a beaker, add an appropriate amount of water-based solvent, and dissolve it while stirring. Then, make the particles completely dissolved by ultrasonic for 10 min. The water-based solvent is deionized water, and the amount of ZnSO4 ensures that the concentration of ZnSO4 in the electrolyte prepared in this example is 2 mol / L.

[0048] (2) Add acetylcysteine to the mixed solvent and supplement the water-based solvent to reach a specific concentration. Use a magnetic stirrer for magnetic stirring for 1 h, and then use an ultrasonic disperser for ultrasonic dispersion for 1 h to achieve uniform mixing. Then, let it stand for 1 h to obtain a zinc ion battery zinc sulfate electrolyte containing acetylcysteine additive. The water-based solvent is deionized water, the specific concentration of acetylcysteine is 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte is 2 mol / L. The preparation of the zinc ion battery electrolyte is completed.

[0049] Example 5

[0050] A zinc ion battery electrolyte containing alanylalanine additive is prepared by the following method:

[0051] (1) Zinc ion battery electrolyte preparation: In the environment of room temperature and normal pressure air (25℃), take the zinc sulfate heptahydrate in a beaker, add an appropriate amount of water-based solvent, and dissolve it while stirring. Then, make the particles completely dissolved by ultrasonic for 10 min. The water-based solvent is deionized water, and the amount of ZnSO4 ensures that the concentration of ZnSO4 in the electrolyte prepared in this example is 2 mol / L.

[0052] (2) Add alanylalanine to the mixed solvent and supplement the water-based solvent to reach a specific concentration. Use a magnetic stirrer for magnetic stirring for 1 h, and then use an ultrasonic disperser for ultrasonic dispersion for 1 h to achieve uniform mixing. Then, let it stand for 1 h to obtain a zinc ion battery zinc sulfate electrolyte containing alanylalanine additive. The water-based solvent is deionized water, the specific concentration of alanylalanine is 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte is 2 mol / L. The preparation of the zinc ion battery electrolyte is completed.

[0053] Example 6

[0054] A zinc ion battery electrolyte containing glycylalanine additive is prepared by the following method:

[0055] (1) Zinc ion battery electrolyte preparation: In the environment of room temperature and normal pressure air (25℃), take zinc sulfate heptahydrate in a beaker, add appropriate amount of water-based solvent, dissolve while stirring, then completely dissolve the particles by ultrasonic for 10 min. The water-based solvent is deionized water, and the amount of ZnSO4 ensures that the concentration of ZnSO4 in the electrolyte prepared in this example is 2 mol / L.

[0056] (2) Add glycylserine to the mixed solvent, supplement the water-based solvent to reach a specific concentration, use a magnetic stirrer for magnetic stirring for 1 h, and then use an ultrasonic disperser for ultrasonic dispersion for 1 h to achieve uniform mixing, to obtain a mixed solution; then stand for 1 h to obtain a zinc ion battery zinc sulfate electrolyte containing glycylserine additive. The water-based solvent is deionized water, the specific concentration of glycylserine is 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte is 2 mol / L. The preparation of the zinc ion battery electrolyte is completed.

[0057] Example 7

[0058] A pyroglutamic acid additive zinc ion battery electrolyte is prepared by the following method:

[0059] (1) Zinc ion battery electrolyte preparation: In the environment of room temperature and normal pressure air (25℃), take zinc sulfate heptahydrate in a beaker, add appropriate amount of water-based solvent, dissolve while stirring, then completely dissolve the particles by ultrasonic for 10 min. The water-based solvent is deionized water, and the amount of ZnSO4 ensures that the concentration of ZnSO4 in the electrolyte prepared in this example is 2 mol / L.

[0060] (2) Add pyroglutamic acid to the mixed solvent, supplement the water-based solvent to reach a specific concentration, use a magnetic stirrer for magnetic stirring for 1 h, and then use an ultrasonic disperser for ultrasonic dispersion for 1 h to achieve uniform mixing, to obtain a mixed solution; then stand for 1 h to obtain a zinc ion battery zinc sulfate electrolyte containing pyroglutamic acid additive. The water-based solvent is deionized water, the specific concentration of pyroglutamic acid is 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte is 2 mol / L. The preparation of the zinc ion battery electrolyte is completed.

[0061] Example 8

[0062] A prolyl glycine additive zinc ion battery electrolyte is prepared by the following method:

[0063] (1) Zinc ion battery electrolyte preparation: In the environment of room temperature and normal pressure air (25℃), take zinc sulfate heptahydrate in a beaker, add an appropriate amount of water-based solvent, dissolve while stirring, then completely dissolve the particles by ultrasonic for 10 min. The water-based solvent is deionized water, and the amount of ZnSO4 ensures that the concentration of ZnSO4 in the electrolyte prepared in this example is 2 mol / L.

[0064] (2) Add prolyl glycine to the mixed solvent and supplement water-based solvent to reach a specific concentration. Use a magnetic stirrer for magnetic stirring for 1 h, and then use an ultrasonic disperser for ultrasonic dispersion for 1 h to achieve uniform mixing. A mixed solution is obtained. Then, after standing for 1 h, a zinc ion battery zinc sulfate electrolyte containing a prolyl glycine additive is obtained. The water-based solvent is deionized water, the specific concentration of prolyl glycine is 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte is 2 mol / L. The preparation of the zinc ion battery electrolyte is completed.

[0065] Example 9

[0066] A zinc ion battery electrolyte containing a serine aspartate additive is prepared as follows:

[0067] (1) Zinc ion battery electrolyte preparation: In the environment of room temperature and normal pressure air (25℃), take zinc sulfate heptahydrate in a beaker, add an appropriate amount of water-based solvent, dissolve while stirring, then completely dissolve the particles by ultrasonic for 10 min. The water-based solvent is deionized water, and the amount of ZnSO4 ensures that the concentration of ZnSO4 in the electrolyte prepared in this example is 2 mol / L.

[0068] (2) Add serine aspartate to the mixed solvent and supplement water-based solvent to reach a specific concentration. Use a magnetic stirrer for magnetic stirring for 1 h, and then use an ultrasonic disperser for ultrasonic dispersion for 1 h to achieve uniform mixing. A mixed solution is obtained. Then, after standing for 1 h, a zinc ion battery zinc sulfate electrolyte containing a serine aspartate additive is obtained. The water-based solvent is deionized water, the specific concentration of serine aspartate is 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte is 2 mol / L. The preparation of the zinc ion battery electrolyte is completed.

[0069] Example 10

[0070] A zinc ion battery electrolyte containing a glycyl leucine additive is prepared as follows:

[0071] (1) Zinc ion battery electrolyte preparation: In the environment of room temperature and normal pressure air (25℃), the zinc sulfate heptahydrate was weighed in a beaker, and an appropriate amount of water-based solvent was added. After stirring and dissolving, the particles were completely dissolved by ultrasonic for 10 min. The water-based solvent was deionized water, and the amount of ZnSO4 was ensured to have a concentration of 2 mol / L in the electrolyte prepared in this embodiment.

[0072] (2) Glycyl leucine was added to the mixed solvent, and water-based solvent was added to reach a specific concentration. Magnetic stirring was performed for 1 h, and ultrasonic dispersion was performed for 1 h using an ultrasonic disperser to achieve uniform mixing. The mixed solution was obtained. After standing for 1 h, the zinc ion battery zinc sulfate electrolyte containing glycyl leucine additive was obtained. The water-based solvent was deionized water, the specific concentration of glycyl leucine was 0.1 mol / L, and the specific concentration of ZnSO4 in the prepared zinc ion battery electrolyte was 2 mol / L. The preparation of the zinc ion battery electrolyte was completed.

[0073] Test Example 1

[0074] The electrolyte prepared in Example 1 was assembled into a button symmetric cell with zinc foil and glass fiber separator (referred to as the experimental group);

[0075] The 2M ZnSO4 electrolyte was assembled into a button symmetric cell with zinc foil and glass fiber separator (referred to as the control group);

[0076] The assembly sequence of the button symmetric cells of the experimental group and the control group was as follows: positive shell, zinc sheet, 150 μL electrolyte, separator, zinc sheet, stainless steel gasket, stainless steel spring and negative shell; After assembly, the battery was pressed using a punch press. The charge-discharge test was carried out at a current density of 1 mA cm -2 , and a capacity of 1 mAh cm -2 The test results are shown in Figure 1 .

[0077] It can be seen that the overpotential of the Zn||Zn symmetric cell of the experimental group is low (only ~ 35 mV after stable cycling), which provides stable cycling for more than 3500 h; while the overpotential of the Zn||Zn symmetric cell of the control group is ~ 58 mV, and the overpotential decreases sharply with the cycle. After cycling for ~ 100 h, the pure zinc symmetric cell using ordinary electrolyte has a sharp drop in voltage after 200 hours of cycling, which is a typical "soft short circuit" phenomenon caused by zinc dendrite growth. When the zinc dendrites of the two electrodes contact each other, electrons will directly pass through the separator to form a short circuit path, causing the cycle to be interrupted. It shows that the improved electrolyte effectively guides the uniform deposition of zinc ions, avoids the formation of dendrites, and inhibits the occurrence of hydrogen evolution reaction, preventing the short circuit of the battery.

[0078] Test Example 2

[0079] The electrolyte prepared in Example 1 was assembled with zinc foil and glass fiber separator into a button symmetric cell (denoted as experimental group);

[0080] The 2M ZnS04electrolyte was assembled with zinc foil and glass fiber separator into a button symmetric cell (denoted as control group);

[0081] The assembly sequence of the button symmetric cell of the experimental group and the control group was in turn: positive shell, zinc sheet, 150 μL electrolyte, separator, zinc sheet, stainless steel gasket, stainless steel spring and negative shell; after assembly, the battery was pressed using a punch press. The charge-discharge test was carried out at a current density of 5 mA cm -2 , and a capacity of 1 mAh cm -2 , and the test results are shown in Figure 2 .

[0082] As shown in Figure 2 , under the condition of high current density of 5 mA cm -2 and capacity of 1 mAh cm -2 , the performance of the control group Zn||Zn symmetric cell was obviously limited. The test data showed that the control group Zn||Zn symmetric cell appeared a sharp rise in voltage after 100 hours of cycling. This is a typical "soft short circuit" phenomenon caused by zinc dendrite growth. This failure behavior is mainly due to the aggravation of zinc deposition non-uniformity under high current density: as the cycle proceeds, the electric field distribution on the electrode surface becomes more uneven, leading to preferential deposition of zinc ions in local areas, forming dendrites and eventually triggering a hard short circuit, causing the battery to completely fail. It can also be seen that the overpotential of the curve of the experimental group Zn||Zn symmetric cell is low (only ~ 68 mV after stable cycling), providing stable cycling for more than 1800 h; this indicates that the experimental group forms a dynamic barrier to inhibit dendrite growth and hydrogen evolution reaction, allowing the battery to maintain a stable interface environment under high current density.

[0083] Test Example 3

[0084] The electrolyte prepared in Example 1 was assembled with zinc foil, glass fiber separator and I2 positive electrode sheet into a button full cell (denoted as experimental group);

[0085] The 2M ZnS04electrolyte was assembled with zinc foil, glass fiber separator and I2 positive electrode sheet into a button full cell (denoted as control group);

[0086] The I2 positive electrode sheet is a commercially available I2 material: polyvinylidene fluoride: conductive carbon black = 8: 1: 1 ratio after coating and drying to obtain the sheet.

[0087] The assembly sequence of the button full cell in the experimental group and the control group is as follows: positive shell, I2 positive electrode sheet, 150 muL electrolyte, diaphragm, zinc sheet, stainless steel gasket, stainless steel spring and negative shell; after assembly, the battery is pressed using a punch press. The charge-discharge test is carried out at a rate of 5A / g (1C=211mAh g -1 ) to obtain the test results as shown in Figure 3 .

[0088] The full cell cycle performance test results further verify the significant advantages of the present application. The control group battery shows obvious capacity attenuation after 7500 cycles, and the capacity retention rate is reduced to less than 70% of the initial value. This performance degradation is mainly due to two key factors: first, the continuous growth of dendrites on the surface of the zinc negative electrode leads to the continuous consumption of active materials; second, the shuttle effect of polyiodide leads to irreversible loss of positive electrode materials and continuous consumption of electrolyte components. In contrast, the experimental group battery using the ANS modified electrolyte shows breakthrough cycle stability. The data shows that the battery can still maintain a reversible capacity of 160mAh g -1 after 55000 cycles, with a very high capacity retention rate. This excellent performance is derived from the multiple protection mechanisms of the ANS additive: on the negative side, the dynamic interfacial layer formed by the peptide bond molecules effectively inhibits dendrite growth, so that the zinc deposition / stripping efficiency always maintains a very high level; on the positive side, the ANS additive molecules block the shuttle of polyiodide through electrostatic repulsion.

[0089] The electrolyte provided by other embodiments is tested according to the above method, and compared with the unmodified electrolyte, it shows inhibition effect on hydrogen evolution reaction, flatter overpotential and better cycle stability, and the coulombic efficiency is improved, so it further illustrates the effect of the zinc ion battery additive based on the peptide bond interfacial regulation proposed in the present application on the cycle performance improvement of the battery, and the significant effect of inhibiting the dendrite growth and hydrogen evolution reaction of the zinc ion battery.

[0090] The present application includes but is not limited to the above embodiments, any equivalent replacement or partial improvement made under the principle of the present application will be considered within the protection scope of the present application.

Claims

1. An additive for an aqueous zinc-ion battery electrolyte, wherein the additive is a peptide-bonded compound composed of amino acids or small molecule peptides; wherein the amino acid residues in the peptide-bonded compound are one or more of glycine (Gly), alanine (Ala), serine (Ser), cysteine ​​(Cys), aspartic acid (Asp), glutamic acid (Glu), histidine (His), and arginine (Arg).

2. The aqueous zinc-ion battery electrolyte additive according to claim 1, characterized in that: The amino acid residue is one or more of glycine (Gly), alanine (Ala), and histidine (His).

3. The aqueous zinc-ion battery electrolyte additive according to claim 1, characterized in that: The peptide bond compound is one or more of a dipeptide or a tripeptide.

4. The aqueous zinc-ion battery electrolyte additive according to claim 1, characterized in that: The additive is one or more of the following: β-alanyl-1-methylhistidine, β-alanylhistidine (carnosine, β-Ala-His), glycylglycine (Gly-Gly), and acetylcysteine ​​(Ac-Cys).

5. An aqueous zinc-ion battery electrolyte, characterized in that, The electrolyte comprises an aqueous solvent, a zinc salt, and an aqueous zinc-ion battery electrolyte additive as described in any one of claims 1 to 4; the concentration of the electrolyte additive is 0.02 to 0.2 mol / L.

6. The aqueous zinc-ion battery electrolyte according to claim 5, characterized in that: The aqueous solvent is one or more of deionized water, heavy water, and superheavy water; the zinc salt is one or more of zinc sulfate (ZnSO4), zinc trifluoromethanesulfonate (Zn(OTf)2), zinc chloride (ZnCl2), and zinc nitrate (Zn(NO3)2).

7. The aqueous zinc-ion battery electrolyte according to claim 5, characterized in that: The concentration of zinc salt in the electrolyte is 1–3 mol / L; the concentration of electrolyte additive in the electrolyte is 0.02–0.2 mol / L.

8. A method for preparing an aqueous zinc-ion battery electrolyte as described in any one of claims 5 to 7, characterized in that: The method steps are as follows: (1) In an environment of room temperature and normal pressure (25℃), weigh zinc salt into a beaker, add an appropriate amount of aqueous solvent, stir while adding to dissolve, and then sonicate for 5 min to 30 min to completely dissolve the particles to obtain a mixed solution. (2) Add the electrolyte additive of claim 1 to the mixed solution, mix evenly, and let stand for 15 min to 60 min to obtain the electrolyte of the present invention.

9. The method for preparing an aqueous zinc-ion battery electrolyte according to claim 8, characterized in that: The electrolyte additive and mixed solvent are mixed evenly by magnetic stirring and ultrasonic dispersion.

10. An aqueous zinc-ion battery, characterized in that: The electrolyte of the battery is the aqueous zinc-ion battery electrolyte as described in any one of claims 5 to 7.

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