Amino acid in-situ modified zinc negative electrode material and preparation method and application thereof

Abstract

The invention provides an amino acid in-situ modified zinc negative electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: immersing a zinc negative electrode material in an amino acid aqueous solution for etching to obtain the amino acid in-situ modified zinc negative electrode material. The zinc negative electrode material is subjected to in-situ etching modification by using amino acid, the raw material is low in cost, safe, non-toxic and environment-friendly, uniform deposition and stripping of zinc ions in the charging and discharging process of the battery are realized, and the cycle performance and the rate capability of the symmetrical battery are effectively improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of aqueous zinc ion batteries, in particular to an amino acid in-situ modified zinc negative electrode material and a preparation method and application thereof. BACKGROUND

[0002] In recent years, the environmental problems caused by the frequent use of coal energy have made it challenging to adhere to the principle of sustainable development in today's era, and the development of renewable energy has become increasingly important for reducing carbon emissions and environmental pollution. The emergence of large-scale energy storage technology has undoubtedly alleviated the intermittency problem of renewable energy. At present, electricity has emerged as a new form of renewable energy, in which wind energy, solar energy and other energy are widely used in power energy conversion, and in the field of energy storage, secondary batteries represented by lithium ion batteries (LIBs) cannot be ignored.

[0003] However, due to the low natural abundance and high price of metal lithium, the commercialization of lithium ion batteries for large-scale energy storage is limited. At the same time, due to the toxicity and flammability of the organic electrolyte used in LIBs, there are safety problems that cannot be ignored. In order to solve these problems, we urgently need to find a way to replace lithium ion batteries.

[0004] At present, aqueous rechargeable zinc ion batteries (ARZIBs) have high energy density potential and fast charging and discharging capacity due to the high natural abundance of zinc, high volume capacity of zinc metal, high ionic conductivity, high safety of aqueous electrolyte, and flexible environmental-friendly structural design, which are strong candidates for the next generation of energy storage technology. Of course, the zinc metal negative electrode also has problems such as zinc dendrite growth, hydrogen evolution reaction (HER), surface passivation, etc., which hinder the commercialization of zinc ion batteries. Among these problems, the rampant dendrite growth is one of the key problems, which can cause short circuit of the battery and affect the service life of the battery. Researchers have developed many control measures such as interface control, electrolyte engineering, separator modification, and structural design to solve this problem.

[0005] Among them, the negative electrode control can optimize the interface characteristics of the zinc negative electrode and the electrolyte by isolating the direct contact between zinc and the electrolyte, inhibit the side reaction, guide the uniform deposition of zinc ions, and improve the kinetic performance. In addition, the formation of a zincophilic interface also has a better effect on the improvement of ion transport kinetics and the realization of uniform deposition of zinc ions. We urgently need a simple and efficient method to modify and modify the negative electrode, realize the uniform deposition of zinc ions on the surface of the zinc negative electrode, and improve the cycle stability of the battery, and promote the development of aqueous zinc ion batteries. SUMMARY

[0006] In view of the above-mentioned disadvantages of the prior art, the purpose of the present application is to provide an amino acid in-situ modified zinc negative electrode material, a preparation method and application thereof, for solving the problem of poor cycle stability of the existing aqueous zinc ion battery, which affects the service life of the battery.

[0007] To achieve the above-mentioned purpose and other related purposes, the present application provides a preparation method of an amino acid in-situ modified zinc negative electrode material, wherein the zinc negative electrode material is immersed in an aqueous amino acid solution for etching to obtain the amino acid in-situ modified zinc negative electrode material.

[0008] Preferably, the aqueous amino acid solution is an aqueous solution of one or more of serine, threonine, glycine, alanine, leucine, tryptophan, and lysine.

[0009] Preferably, the concentration of the aqueous amino acid solution is 0.1-3M.

[0010] Preferably, the etching temperature is 20-40℃, and the etching time is 5-20h.

[0011] Preferably, the zinc negative electrode material is a zinc foil with a thickness of 20-100μm.

[0012] More preferably, the zinc foil further comprises a sandpaper polishing process before etching, and the mesh number of the sandpaper is 500-1500.

[0013] The present application also provides an amino acid in-situ modified zinc negative electrode material prepared by the above-mentioned preparation method.

[0014] The present application also provides an application of the above-mentioned amino acid in-situ modified zinc negative electrode material in an aqueous zinc ion battery.

[0015] The present application also provides an aqueous zinc ion battery, wherein at least one electrode of the aqueous zinc ion battery adopts the above-mentioned amino acid in-situ modified zinc negative electrode material.

[0016] Preferably, the aqueous zinc ion battery comprises a symmetric battery, an asymmetric battery, and a full battery.

[0017] More preferably, the symmetric battery comprises a zinc foil positive electrode, a zinc foil negative electrode, an electrolyte, and a separator.

[0018] More preferably, the asymmetric battery comprises a zinc foil negative electrode, a copper foil positive electrode, an electrolyte, and a separator.

[0019] More preferably, the full battery comprises a zinc foil negative electrode, a manganese-based or vanadium-based oxide positive electrode, an electrolyte, and a separator.

[0020] More preferably, the zinc foil positive electrode and the zinc foil negative electrode both adopt the amino acid in-situ modified zinc negative electrode material.

[0021] More preferably, the electrolyte is an aqueous solution of a soluble zinc salt, which is selected from any one of zinc sulfate (ZnSO4) aqueous solution, zinc triflate (Zn(CF3SO3)2) aqueous solution and zinc chloride (ZnCl2) aqueous solution. More preferably, the separator is selected from one of glass fiber separator and microporous filter paper.

[0022] More preferably, the manganese-based or vanadium-based oxide positive electrode adopts a material selected from one of manganese dioxide (MnO2), manganese oxyhydroxide (MnOOH), vanadium trioxide (V2O3), vanadium pentoxide (V2O5), vanadium trioxide (V2O3), vanadium hexoxide (V6O 13 ) and vanadium disulfide (VS2).

[0023] As described above, the present application has the following beneficial effects: (1) The zinc negative electrode material is in-situ etched and modified using amino acid, the raw material is low-cost, safe, non-toxic and environmentally friendly, and the uniform deposition and stripping of zinc ions during the charging and discharging process of the battery is realized, which effectively improves the cycle performance and rate performance of the symmetrical battery. (2) The aqueous zinc ion battery assembled using the in-situ modified zinc negative electrode material has better coulombic efficiency and better full battery cycle stability. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the SEM image of the surface morphology of the zinc foil prepared in Example 1 (left) and Comparative Example 1 (right).

[0025] Figure 2 is the cycle life comparison chart of the symmetrical battery assembled by the zinc foil prepared in Examples 1-3 and Comparative Example 1 under the test conditions of current density of 1 mA cm -2 , capacity of 1 mAh cm -2 .

[0026] Figure 3 is the coulombic efficiency comparison chart of the half battery assembled by the zinc foil prepared in Examples 3-5 and Comparative Example 1 under the test conditions of current density of 1 mA cm -2 , capacity of 1 mAh cm -2 .

[0027] Figure 4 is the cycle stability comparison chart of the full battery assembled by the zinc foil prepared in Example 1 and Comparative Example 1 under the test conditions of 1 A g-1. DETAILED DESCRIPTION

[0028] Following, the advantages and effects of the present application can be easily understood by those skilled in the art from the description. The present application can also be implemented or applied by different specific embodiments, and the details in the description can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0029] It should be noted that the process equipment or device not specifically mentioned in the following examples is the conventional equipment or device in the art.

[0030] In addition, it should be understood that the one or more method steps mentioned in the present application do not exclude that there can be other method steps before and after the combination steps or other method steps can be inserted between the explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination connection relationship between the one or more devices / apparatuses mentioned in the present application does not exclude that there can be other devices / apparatuses before and after the combination devices / apparatuses or other devices / apparatuses can be inserted between the two explicitly mentioned devices / apparatuses, unless otherwise specified. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool to identify each method step, and is not a limitation on the arrangement order of each method step or a limitation on the range of the present application, and the change or adjustment of the relative relationship is also considered as the range of the present application that can be implemented without substantial change of the technical content.

[0031] The battery model used in the embodiments of the present application is CR2032.

[0032] The specific size of the battery component in the embodiments of the present application is as follows: The zinc foil is a round sheet with a thickness of 50 μm and a diameter of 15 mm; the separator is a glass fiber separator round sheet with a thickness of 1 mm and a diameter of 19 mm; the copper foil is a round sheet with a thickness of 20 μm and a diameter of 15 mm; the current collector carbon paper is a round sheet with a diameter of 12 mm. The electrolyte used is a 2M zinc sulfate solution.

[0033] The analysis method in the present application is as follows: Using a new wei battery tester, the battery is tested for charge and discharge and coulomb efficiency under different current densities and capacities, and the influence of using different zinc foils is analyzed.

[0034] Embodiment 1 The present embodiment provides a preparation method of in-situ modification of zinc negative electrode material by amino acid, comprising the following steps: (1) The zinc foil with a thickness of 50 µm is cut into a size of 6×8 cm and polished to a uniform surface with 1500 mesh sandpaper; (2) Add 0.151 g of glycine to 20 mL of deionized water at room temperature and stir until fully dissolved to prepare a 0.1 M glycine aqueous solution; (3) The zinc foil was placed in the above-mentioned glycine aqueous solution and etched at 25°C. After standing for 18 hours, it was taken out and rinsed three times with deionized water. It was dried under natural conditions to obtain glycine-modified zinc foil, which was recorded as Gly@Zn.

[0035] Comparative Example 1 A 50-µm zinc foil was cut into a size of 6 × 8 cm and polished with 1500-grit sandpaper until the surface was uniform, which was recorded as BareZn.

[0036] Example 2 This embodiment provides a method for preparing an amino acid in situ modified zinc negative electrode material, comprising the following steps: (1) Cut a 50µm thick zinc foil into 6×8cm size and polish it with 1500 grit sandpaper until the surface is uniform; (2) Add 0.238 g of threonine to 20 mL of deionized water at room temperature and stir until fully dissolved to obtain a 0.1 M threonine aqueous solution; (3) The zinc foil was placed in the above-mentioned threonine aqueous solution for etching, and then taken out after standing for 18 hours. It was rinsed three times with deionized water and dried under natural conditions to obtain threonine-modified zinc foil, which was recorded as Thr@Zn.

[0037] Example 3 This embodiment provides a method for preparing an amino acid in situ modified zinc negative electrode material, comprising the following steps: (1) Cut a 50µm thick zinc foil into 6×8cm size and polish it with 1500 grit sandpaper until the surface is uniform; (2) Add 0.210 g of serine to 20 mL of deionized water at room temperature and stir until fully dissolved to obtain a 0.1 M serine aqueous solution; (3) The zinc foil was placed in the above-mentioned serine aqueous solution for etching, and then taken out after standing for 18 hours. It was rinsed three times with deionized water and dried under natural conditions to obtain serine-modified zinc foil, which was recorded as Ser@Zn.

[0038] Example 4 This embodiment provides a method for preparing an amino acid in situ modified zinc negative electrode material, comprising the following steps: (1) Cut a 50µm thick zinc foil into 6×8cm size and polish it with 1500 grit sandpaper until the surface is uniform; (2) Add 1.051 g of serine to 20 mL of deionized water at room temperature and stir until fully dissolved to obtain a 0.5 M serine aqueous solution; (3) Put the zinc foil into the above serine aqueous solution for etching, take it out after standing for 18 h, rinse with deionized water for three times, and dry under natural conditions to obtain a serine modified zinc foil, denoted as Ser@Zn-0.5.

[0039] Example 5 The present example provides a preparation method of in-situ modification of zinc negative electrode material by amino acid, comprising the following steps: (1) Cut the zinc foil with a thickness of 50 pm into a size of 6x8 cm, and polish it with 1500 mesh sandpaper until the surface is uniform; (2) At room temperature, add 4.204 g of serine to 20 mL of deionized water, stir until fully dissolved to obtain a serine aqueous solution with a concentration of 2 M; (3) Put the zinc foil into the above serine aqueous solution for etching, take it out after standing for 18 h, rinse with deionized water for three times, and dry under natural conditions to obtain a serine modified zinc foil, denoted as Ser@Zn-2.

[0040] Example 6 The SEM surface contrast images of Example 1 and Comparative Example 1 are taken respectively. After the soaking treatment of amino acid, etching marks are generated on the surface of the zinc foil, as shown in Figure 1 .

[0041] Example 7 The zinc foils of Examples 1-3 and Comparative Example 1 are used as positive and negative electrode sheets to assemble symmetric batteries. The assembly process is as follows: negative shell, spring, gasket, zinc foil, glass fiber separator, zinc foil, and positive shell. When assembling, the modified surface of the zinc foil faces the separator. The amount of electrolyte added on the separator is 160 pL, and a battery packaging machine is used for pressing and packaging. Figure 2 is a comparison diagram of the charge-discharge curves of symmetric batteries assembled with different zinc foils under a current density of 1 mA cm -2 , and a specific capacity of 1 mAh cm -2 . As can be seen from the diagram, the cycle stability of the symmetric batteries using amino acid modified zinc foils has been improved, especially the battery using Ser@Zn negative electrode has a stable cycle of more than 1600 h.

[0042] Example 8 A copper foil disc with a diameter of 15 mm is used as the positive electrode sheet of the button cell, and the zinc foils of Examples 3-5 and Comparative Example 1 are used as the negative electrode sheet. The remaining steps are the same as those of the symmetric button cell to assemble a zinc-copper half-cell. As Figure 3 shown, the Coulomb efficiency stability of the half-cell using different concentrations of serine modified zinc foils has been improved under a current density of 1 mA cm -2 , and a specific capacity of 1 mAh cm -2 .

[0043] Example 9: The electrode sheet with 1.4 mg cm-2 of MnOOH loaded at a diameter of 12 mm -2 The full cell was assembled in the same way as the symmetric button cell, with the electrode sheet of Example 1 and Comparative Example 1 as the positive electrode sheet, the zinc foil of Example 1 and Comparative Example 1 as the negative electrode sheet, and the rest of the steps being the same as the symmetric button cell. The assembled full cell was tested for long cycle performance at a current density of 1 A g-1, and the results are shown in Figure 6. Figure 4 -1 As can be seen from Figure 6, the Ser@Zn||MnOOH using the modified zinc foil exhibits more excellent electrochemical performance, with a higher capacity retention rate after 500 cycles.

[0044] The above examples are intended to illustrate the embodiments disclosed in the present application and should not be understood as limiting the present application. In addition, various modifications listed herein and changes to the methods and compositions of the present application will be apparent to those skilled in the art, without departing from the scope and spirit of the present application. Although the present application has been described in detail with reference to various specific preferred embodiments, it should be understood that the present application should not be limited to only these specific embodiments. In fact, various modifications as described above to those skilled in the art to obtain the present application should be included within the scope of the present application.​

Claims

1. A method for preparing an amino acid in situ modified zinc negative electrode material, characterized in that: The zinc negative electrode material is immersed in an amino acid aqueous solution for etching to obtain an amino acid in situ modified zinc negative electrode material.

2. The preparation method according to claim 1, wherein: The amino acid aqueous solution is an aqueous solution of one or more of serine, threonine, glycine, alanine, leucine, tryptophan, and lysine.

3. The preparation method according to claim 2, wherein: The concentration of the amino acid aqueous solution is 0.1~3M.

4. The preparation method according to claim 1, wherein: The etching temperature is 20~40℃, and the etching time is 5~20h.

5. The preparation method according to claim 1, wherein: The zinc negative electrode material is a zinc foil with a thickness of 20-100 μm.

6. An amino acid in situ modified zinc negative electrode material prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the amino acid in situ modified zinc negative electrode material as claimed in claim 6 in an aqueous zinc ion battery.

8. An aqueous zinc ion battery, characterized in that: At least one electrode of the aqueous zinc ion battery adopts the amino acid in situ modified zinc negative electrode material as claimed in claim 6.

9. The aqueous zinc ion battery according to claim 8, wherein: The aqueous zinc ion battery includes a symmetrical battery, an asymmetrical battery and a full battery.

10. The aqueous zinc ion battery according to claim 9, wherein: The symmetrical battery comprises a zinc foil positive electrode, a zinc foil negative electrode, an electrolyte and a separator; The asymmetric battery comprises a zinc foil negative electrode, a copper foil positive electrode, an electrolyte and a separator; The full battery comprises a zinc foil negative electrode, a manganese or vanadium oxide positive electrode, an electrolyte and a separator; The zinc foil positive electrode and the zinc foil negative electrode are both zinc negative electrode materials modified in situ with amino acids; The electrolyte is a soluble zinc salt aqueous solution, and the soluble zinc salt aqueous solution is selected from any one of a zinc sulfate aqueous solution, a zinc trifluoromethanesulfonate aqueous solution and a zinc chloride aqueous solution; The diaphragm is selected from one of a glass fiber diaphragm and a microporous filter paper; The material used for the manganese or vanadium oxide positive electrode is selected from one of manganese dioxide, manganese oxyhydroxide, hexavanadium trioxide and vanadium disulfide.

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