CN114824152B - Preparation method and application of zinc cathode modified by metal complex - Google Patents

Abstract

The invention discloses a preparation method and application of a zinc cathode modified by a metal complex, belonging to the technical field of electrochemical energy storage. The invention provides a method for preparing a metal complex modified zinc cathode by taking a metal compound as a raw material, and further provides application of the metal complex modified zinc cathode in an aqueous zinc-based battery. The preparation method has the advantages of simple process, wide and easily available experimental raw materials, low cost and suitability for large-scale production. The prepared water-based zinc-based battery has good electrochemical performance, the growth of dendrites of the negative electrode is obviously inhibited, and the cycle stability and the rate capability of electrochemical energy storage devices such as batteries are obviously improved.

Description

A kind of preparation method and application of zinc negative electrode modified by metal complex

technical field

The invention belongs to the technical field of electrochemical energy storage, and in particular relates to a method for preparing a zinc negative electrode modified by a metal complex and its application in an aqueous zinc-based battery.

Background technique

At present, most of the world's energy comes from fossil fuels. With the progress of society, human's demand for energy is increasing, which inevitably has a serious impact on the environment and the sustainable development of human beings. Therefore, the development of alternative New sources of energy from traditional fossil energy sources and the realization of efficient energy storage technologies are of paramount importance. Lithium-ion batteries, as an energy storage device, have attracted much attention due to their practical applications in portable electronics and vehicles. Compared with other secondary batteries, lithium-ion batteries have excellent characteristics such as flexibility, high efficiency and long cycle life. However, due to the high cost of metallic lithium and the flammable and toxic properties of organic electrolytes, these limitations greatly limit the development and application of lithium-ion batteries.

Aqueous Zn-ion batteries have become one of the most attractive candidates for energy storage owing to the abundant reserves of Zn metal and the high safety of aqueous electrolytes. In recent years, people have turned their attention to zinc-based batteries. Compared with other metal anodes, zinc has a higher theoretical capacity and the lowest redox potential. However, the zinc electrode as the negative electrode is very easy to form dendrites during the continuous dissolution/deposition process, and as the number of cycles increases, the deposited zinc will selectively grow on the dendrites, which will eventually lead to a short circuit through the separator or deactivation by peeling off. Greatly reduce cycle life. The further development of zinc-ion batteries is seriously restricted, so the optimization of zinc anode is of great significance to improve the performance of zinc-ion batteries.

Many efforts have been made to solve this problem. For example, electrolyte additives (sodium dodecyl sulfate (SDS), poly(ethylene glycol), ethyl phosphate (TEP), cetyltrimethylammonium bromide (CTAB), thiourea, and polyacrylamide ( PAM)) has been shown to have a positive effect on improving the stability of Zn anodes. In addition, coating a protective layer on the Zn anode has been proven to be an effective measure. For example, the prior art discloses a coating formed by a calcium carbonate paint with nanopores, a sheet-like graphene oxide layer deposited on the surface of the zinc negative electrode, and a TiO coating _etc. deposited on the surface of the zinc negative electrode by atomic layer deposition, The possibility of selective growth of dendrites is eliminated to some extent.

However, electrolyte additives may reduce the ionic conductivity of aqueous zinc-ion battery electrolytes, and coating zinc anodes by atomic layer deposition is too expensive and precise to be applied in large-scale industrial production. Therefore, we need to develop a method for modifying zinc anode with simple process and low cost.

Contents of the invention

The object of the present invention is to provide a zinc negative electrode modified by a metal complex and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

In order to achieve the above object, the present invention provides the following technical solutions: a method for preparing a zinc negative electrode modified by a metal complex, comprising the following steps:

S1: Use acid to titrate the ammonium salt solution to acidity to obtain a mixed solution;

S2: adding metal compound raw materials to the mixed solution in the above steps;

S3: ultrasonically disperse the solution obtained in the above steps, and then add a zinc negative electrode;

S4: Stir the solution obtained in the above steps under the condition of an oil bath, wherein the temperature of the oil bath is set at 60-80° C., and the stirring time is 2-4 hours;

S5: washing the product obtained in the above steps for 2 to 3 times with a washing solvent, and drying in a vacuum drying oven after washing to obtain a metal complex-modified zinc negative electrode.

Preferably, the water-based zinc-based battery is characterized in that it uses zinc sheet, porous zinc, zinc/carbon composite material and zinc alloy as the negative electrode, and the aqueous solution as the electrolyte.

Preferably in any of the above schemes, in step S1, the acid is one or more of formic acid, acetic acid, and oxalic acid in combination.

Preferably in any of the above schemes, in step S1, the ammonium salt is a combination of one or more of ammonium formate, ammonium chloride, and ammonium sulfate, wherein the concentration of the ammonium salt is 0.1-0.5 mol/L , the pH of the mixed solution is 3.6-4.8.

Preferably in any of the above schemes, in step S1, the concentration of the ammonium salt is 0.1-0.3 mol/L, and the pH of the mixed solution is 4.2-4.6.

Preferably in any of the above schemes, in step S1, the concentration of the ammonium salt is 0.2 mol/L, and the pH of the mixed solution is 4.4.

Preferably in any of the above schemes, in step S2, the metal compound raw material includes one or more combinations of aluminum sulfate octadecadecahydrate, aluminum nitrate nonahydrate, aluminum trichloride, and aluminum chloride hexahydrate .

Preferably in any of the above schemes, in step S2, the metal compound raw material includes one or more combinations of ferric nitrate, ferric nitrate nonahydrate, ferric chloride, and ferric chloride hexahydrate.

Preferably in any of the above schemes, in step S2, the metal compound raw material includes one or a combination of copper sulfate and copper chloride.

Preferably in any of the above schemes, in step S2, the metal compound raw material includes one or a combination of manganese acetate and manganese chloride.

In any of the above solutions, preferably, in step S3, the zinc negative electrode includes: zinc sheet, porous zinc, zinc alloy and zinc/carbon composite material.

In any of the above schemes, it is preferred that the zinc alloy includes an alloy formed of zinc and one or more of silver, copper, gold, mercury, tin, aluminum, magnesium, cadmium, lead, titanium and antimony metals

Preferably in any of the above-mentioned schemes, the carbon source in the zinc/carbon composite material comes from graphite containing mesophase carbon microspheres, natural graphite, expanded graphite, artificial graphite, glassy carbon, carbon fiber (such as carbon nanofiber), hard Carbon, soft carbon, activated carbon, porous carbon, carbon cloth, carbon paper, three-dimensional graphite, carbon black, carbon nanotubes (e.g. single-walled carbon nanotubes, multi-walled carbon nanotubes), graphene (e.g. graphene sheets) and above A combination of one or more modified materials of carbon materials.

Preferably in any of the above-mentioned schemes, the carbon source in the zinc/carbon composite material is preferably activated carbon, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanofibers, carbon paper, graphene sheet and carbon cloth. One or more combinations.

Preferably in any of the above solutions, the carbon source in the zinc/carbon composite material is more preferably a combination of one or more of activated carbon, carbon nanofibers and graphene sheets.

Application of metal complex-modified zinc anode in aqueous zinc-based batteries.

Technical effect and advantage of the present invention:

1. The preparation method has simple process, wide and easy-to-obtain experimental raw materials, low cost and is suitable for large-scale production;

2. The zinc negative electrode modified by the technology provided by the present invention is used in an aqueous zinc-based battery, thereby obviously inhibiting the growth of zinc dendrites. After the zinc anode is treated, the electrochemical performance of the battery is significantly improved, showing long cycle stability and excellent rate performance.

Description of drawings

Fig. 1 is the cross-sectional SEM figure of the aluminum metal complex modified zinc negative electrode of Example 1 of the present invention;

Fig. 2 is the cross-sectional SEM figure of the zinc negative electrode of comparative example 1 of the present invention;

Fig. 3 is the zinc ion deposition/dissolution voltage curve of the aluminum metal complex modified zinc symmetric battery of Example 1 of the present invention and the zinc symmetric battery of Comparative Example 1;

Fig. 4 is the SEM picture of the electrode surface after 50 hours of cycle of comparative example 1 symmetrical battery of the present invention;

Fig. 5 is the SEM image of the electrode surface of the aluminum metal complex modified zinc symmetric battery in Example 1 of the present invention after 740 hours of cycling;

Fig. 6 is the cycle performance diagram of zinc negative electrode modified by aluminum metal complex in Example 1 of the present invention and zinc in Comparative Example 1 (Zn/NaV ₃ O ₈ ·1.5H ₂ O battery);

Fig. 7 is a graph of the rate performance of zinc modified by aluminum metal complex coating in Example 1 of the present invention and comparative example 1 zinc (Zn/NaV ₃ O ₈ ·1.5H ₂ O battery).

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings. It should be noted here that the descriptions of these embodiments are used to help understand the present invention, but are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not constitute a conflict with each other.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship indicated by "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device or element Must be in a particular orientation, be constructed in a particular orientation, and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features.

A method for preparing a zinc negative electrode modified by a metal complex, comprising the following steps:

S1: Use acid to titrate the ammonium salt solution to acidity to obtain a mixed solution;

S2: adding metal compound raw materials to the mixed solution in the above steps;

S3: ultrasonically disperse the solution obtained in the above steps, and then add a zinc negative electrode;

S4: Stir the solution obtained in the above steps under the condition of an oil bath, wherein the temperature of the oil bath is set at 60-80° C., and the stirring time is 2-4 hours;

S5: washing the product obtained in the above steps for 2 to 3 times with a washing solvent, and drying in a vacuum drying oven after washing to obtain a metal complex-modified zinc negative electrode.

Specifically, the water-based zinc-based battery is characterized in that it uses zinc sheet, porous zinc, zinc/carbon composite material and zinc alloy as the negative electrode, and the aqueous solution as the electrolyte.

Specifically, in step S1, the acid is one or a combination of formic acid, acetic acid, and oxalic acid.

Specifically, in step S1, the ammonium salt is a combination of one or more of ammonium formate, ammonium chloride, and ammonium sulfate, wherein the concentration of the ammonium salt is 0.1-0.5 mol/L, and the pH of the mixed solution is 3.6- 4.8.

Specifically, in step S1, the concentration of the ammonium salt is 0.1-0.3 mol/L, and the pH of the mixed solution is 4.2-4.6.

Specifically, in step S1, the concentration of the ammonium salt is 0.2 mol/L, and the pH of the mixed solution is 4.4.

Specifically, in step S2, the metal compound raw material includes one or more combinations of aluminum sulfate octadecahydrate, aluminum nitrate nonahydrate, aluminum trichloride, and aluminum chloride hexahydrate.

Specifically, in step S2, the metal compound raw material includes one or more combinations of ferric nitrate, ferric nitrate nonahydrate, ferric chloride, and ferric chloride hexahydrate.

Specifically, in step S2, the metal compound raw material includes one or a combination of copper sulfate and copper chloride.

Specifically, in step S2, the metal compound raw material includes one or a combination of manganese acetate and manganese chloride.

Specifically, in step S3, the zinc negative electrode includes: zinc sheet, porous zinc, zinc alloy and zinc/carbon composite material.

Specifically, zinc alloys include alloys formed of zinc and one or more of silver, copper, gold, mercury, tin, aluminum, magnesium, cadmium, lead, titanium, and antimony metals

Specifically, the carbon source in the zinc/carbon composite material comes from graphite containing mesophase carbon microspheres, natural graphite, expanded graphite, artificial graphite, glassy carbon, carbon fiber (such as carbon nanofiber), hard carbon, soft carbon, activated carbon, porous Carbon, carbon cloth, carbon paper, three-dimensional graphite, carbon black, carbon nanotubes (such as single-walled carbon nanotubes, multi-walled carbon nanotubes), graphene (such as graphene sheets) and modified materials of the above carbon materials One or more combinations.

Specifically, the carbon source in the zinc/carbon composite material is preferably one or more combinations of activated carbon, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanofibers, carbon paper, graphene sheet and carbon cloth.

Specifically, the carbon source in the zinc/carbon composite material is more preferably a combination of one or more of activated carbon, carbon nanofibers and graphene sheets.

Application of metal complex modified zinc anode in zinc ion battery.

Example 1:

0.01 mol of ammonium formate was weighed and dissolved in 50 ml of deionized water, and the ammonium formate solution was titrated with formic acid until the pH reached 4.4 to obtain a buffer solution. Add 0.06g of aluminum sulfate to the buffer solution and ultrasonicate for 15min until completely dissolved, then add 8 pieces of 1cm*1cm commercial zinc flakes to the solution, and place the mixture in a 70°C oil bath and stir vigorously for 3 hours. Take out the stirred zinc sheet, wash it with ethanol and deionized water for 2 to 3 times, place the reacted zinc negative electrode in a vacuum drying oven, and dry it at 60°C for 12 hours to obtain aluminum metal complex-modified zinc negative electrode.

Example 2:

0.02 mol of ammonium formate was weighed and dissolved in 50 ml of deionized water, and the ammonium formate solution was titrated with formic acid until the pH reached 4.4 to obtain a buffer solution. Add 0.06g of aluminum sulfate to the buffer solution and ultrasonicate for 15min until completely dissolved, then add 8 pieces of 1cm*1cm commercial zinc flakes to the solution, and place the mixture in a 70°C oil bath and stir vigorously for 3 hours. Take out the stirred zinc sheet, wash it with ethanol and deionized water for 2 to 3 times, place the reacted zinc negative electrode in a vacuum drying oven, and dry it at 60°C for 12 hours to obtain aluminum metal complex-modified zinc negative electrode.

Example 3:

0.005 mol of ammonium formate was weighed and dissolved in 50 ml of deionized water, and the ammonium formate solution was titrated with formic acid until the pH reached 4.4 to obtain a buffer solution. Add 0.06g of aluminum sulfate to the buffer solution and ultrasonicate for 15min until completely dissolved, then add 8 pieces of 1cm*1cm commercial zinc flakes to the solution, and place the mixture in a 70°C oil bath and stir vigorously for 3 hours. Take out the stirred zinc sheet, wash it with ethanol and deionized water for 2 to 3 times, place the reacted zinc negative electrode in a vacuum drying oven, and dry it at 60°C for 12 hours to obtain aluminum metal complex-modified zinc negative electrode.

Example 4:

0.01 mol of ammonium formate was weighed and dissolved in 50 ml of deionized water, and the ammonium formate solution was titrated with formic acid until the pH reached 3.6 to obtain a buffer solution. Add 0.06g of aluminum sulfate to the buffer solution and ultrasonicate for 15min until completely dissolved, then add 8 pieces of 1cm*1cm commercial zinc flakes to the solution, and place the mixture in a 70°C oil bath and stir vigorously for 3 hours. Take out the stirred zinc sheet, wash it with ethanol and deionized water for 2 to 3 times, place the reacted zinc negative electrode in a vacuum drying oven, and dry it at 60°C for 12 hours to obtain aluminum metal complex-modified zinc negative electrode.

Example 5:

0.01 mol of ammonium formate was weighed and dissolved in 50 ml of deionized water, and the ammonium formate solution was titrated with formic acid until the pH reached 4.8 to obtain a buffer solution. Add 0.06g of aluminum sulfate to the buffer solution and ultrasonicate for 15min until completely dissolved, then add 8 pieces of 1cm*1cm commercial zinc flakes to the solution, and place the mixture in a 70°C oil bath and stir vigorously for 3 hours. Take out the stirred zinc sheet, wash it with ethanol and deionized water for 2 to 3 times, place the reacted zinc negative electrode in a vacuum drying oven, and dry it at 60°C for 12 hours to obtain aluminum metal complex-modified zinc negative electrode.

Embodiment 6:

0.01 mol of ammonium formate was weighed and dissolved in 50 ml of deionized water, and the ammonium formate solution was titrated with formic acid until the pH reached 4.4 to obtain a buffer solution. Add 0.06g of manganese sulfate to the buffer solution and ultrasonicate for 15min until completely dissolved, then add 8 pieces of 1cm*1cm commercial zinc flakes into the solution, and place the mixture in a 70°C oil bath and stir vigorously for 3 hours. Take out the stirred zinc flakes, wash them with ethanol and deionized water for 2 to 3 times, place the reacted zinc negative electrode in a vacuum drying oven, and dry at 60°C for 12 hours to obtain manganese metal complex-modified zinc negative electrode.

Embodiment 7:

0.01 mol of ammonium formate was weighed and dissolved in 50 ml of deionized water, and the ammonium formate solution was titrated with formic acid until the pH reached 4.4 to obtain a buffer solution. After adding 0.06 g of aluminum sulfate to the buffer solution and ultrasonicating for 15 min until it was completely dissolved, a zinc/graphene composite material was added to the solution, and the mixture was placed in an oil bath at 70° C. and stirred vigorously for 3 hours. Take out the stirred zinc negative electrode, wash it with ethanol and deionized water for 2 to 3 times, place the reacted zinc negative electrode in a vacuum drying oven, and dry it at 60°C for 12 hours to obtain aluminum metal complex-modified zinc negative electrode.

Embodiment 8:

0.01 mol of ammonium formate was weighed and dissolved in 50 ml of deionized water, and the ammonium formate solution was titrated with formic acid until the pH reached 4.4 to obtain a buffer solution. After adding 0.06g of aluminum sulfate to the buffer solution and ultrasonicating for 15min until it was completely dissolved, a zinc/activated carbon-carbon composite material was added to the solution, and the mixture was placed in a 70°C oil bath and vigorously stirred for 3 hours. Take out the stirred zinc negative electrode, wash it with ethanol and deionized water for 2 to 3 times, place the reacted zinc negative electrode in a vacuum drying oven, and dry it at 60°C for 12 hours to obtain aluminum metal complex-modified zinc negative electrode.

Embodiment 9:

0.01 mol of ammonium formate was weighed and dissolved in 50 ml of deionized water, and the ammonium formate solution was titrated with formic acid until the pH reached 4.4 to obtain a buffer solution. After adding 0.06 g of aluminum sulfate into the buffer solution and ultrasonicating for 15 minutes until it was completely dissolved, a zinc-copper alloy was added to the solution, and the mixture was placed in an oil bath at 70° C. and stirred vigorously for 3 hours. Take out the stirred zinc negative electrode, wash it with ethanol and deionized water for 2 to 3 times, place the reacted zinc negative electrode in a vacuum drying oven, and dry it at 60°C for 12 hours to obtain aluminum metal complex-modified zinc negative electrode.

Comparative example 1:

Unmodified zinc anode was used as the anode.

The electrochemical properties of the obtained samples were measured as follows:

Using the metal complex modified zinc anode as the electrode, glass fiber (Whatman) as the separator, and 2molL ^-1 ZnSO ₄ as the electrolyte of the symmetrical battery, it was assembled into a CR2025 button Zn//Zn symmetrical battery, The electrochemical performance of the symmetrical battery was tested at a current density of 1mA cm ^-2 (1mAh cm ^-2 ).

Weighed 117 mg of NaV ₃ O ₈ ·1.5H ₂ O (abbreviated as NVO) positive electrode material, added 32 mg of conductive carbon black and ground it thoroughly. Then the 60wt.% binder polytetrafluoroethylene (PTFE) of weighing 16mg is dissolved in the 5ml ethanol, after making it fully disperse after ultrasonic 15 minutes, the material after grinding is added in the ethanol dispersion liquid ultrasonic 2 hours, will disperse A good slurry is rolled out to make pole pieces. The prepared electrode sheets were vacuum-dried at 60° C. for 12 hours, and cut into 1 mg electrode sheets for use. The button-type CR2025 is assembled with NVO electrode as the positive electrode, metal complex-modified zinc anode as the negative electrode, glass fiber (Whatman) as the diaphragm, and 2mol L ^-1 ZnSO ₄ +0.1mol L ^-1 NaSO ₄ as the electrolyte. Aqueous zinc ion battery. The charge and discharge capacity and rate performance of the battery were tested within the voltage range of 0.2-1.4V.

The cycle stability of the symmetrical battery and the full battery was measured, and the specific results are shown in Table 1

Table 1

serial number Symmetrical battery cycle time/h Full battery cycles/n Example 1 740 1520 Example 2 620 890 Example 3 590 840 Example 4 350 660 Example 5 470 740 Example 6 320 630 Example 7 540 820 Example 8 420 710 Example 9 570 830 Comparative example 1 80 380

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (8)

1. A preparation method of a zinc cathode modified by a metal complex is characterized by comprising the following steps: the method comprises the following steps:

s1: titrating the ammonium salt solution to acidity by using acid to obtain a mixed solution;

s2: adding a metal compound raw material into the mixed solution obtained in the step;

s3: carrying out ultrasonic dispersion on the solution obtained in the step, and then adding a zinc cathode;

s4: stirring the solution obtained in the step under the condition of oil bath, wherein the temperature of the oil bath is set to be 60-80 ℃, and the stirring time is 2-4 hours;

s5: washing the product obtained in the step for 2 to 3 times by using a washing solvent, and drying in a vacuum drying oven after washing to obtain a zinc negative electrode modified by a metal complex;

in the step S1, the ammonium salt is one or a combination of ammonium formate, ammonium chloride and ammonium sulfate, wherein the concentration of the ammonium salt is 0.1 to 0.5mol/L, and the pH value of the mixed solution is 3.6 to 4.8;

in step S2, the metal compound raw material comprises one or more of aluminum sulfate octadecahydrate, aluminum nitrate nonahydrate, aluminum trichloride and aluminum chloride hexahydrate;

or in step S2, the metal compound raw material includes one or more of ferric nitrate, ferric nitrate nonahydrate, ferric trichloride and ferric chloride hexahydrate;

or in the step S2, the metal compound raw material comprises one or two of copper sulfate and copper chloride;

or in step S2, the metal compound raw material comprises one or the combination of two of manganese acetate and manganese chloride;

in step S3, the zinc negative electrode includes: zinc flakes, porous zinc, zinc alloys, and zinc/carbon composites;

the carbon source in the zinc/carbon composite material is derived from one or more of mesocarbon microbeads, natural graphite, expanded graphite, glassy carbon, carbon fibers, hard carbon, soft carbon, activated carbon, porous carbon, carbon cloth, carbon paper, carbon black, carbon nanotubes, graphene and modified materials of the above carbon materials.

2. The method for preparing a zinc anode modified by a metal complex according to claim 1, wherein the method comprises the following steps: in step S1, the acid is one or a combination of formic acid, acetic acid, and oxalic acid.

3. The method for preparing a zinc anode modified by a metal complex according to claim 1, wherein the method comprises the following steps: in the step S1, the concentration of the ammonium salt is 0.1 to 0.3mol/L, and the pH of the mixed liquid is 4.2 to 4.6.

4. The method for preparing a zinc negative electrode modified by a metal complex according to claim 3, wherein the method comprises the following steps: in step S1, the concentration of the ammonium salt is 0.2mol/L, and the pH of the mixed solution is 4.4.

5. The method for preparing a zinc anode modified by a metal complex according to claim 1, wherein the method comprises the following steps: the zinc alloy comprises an alloy of zinc with one or more of silver, copper, gold, mercury, tin, aluminium, magnesium, cadmium, lead, titanium and antimony.

6. The method for preparing a zinc anode modified by a metal complex according to claim 1, wherein the method comprises the following steps: the carbon source in the zinc/carbon composite material is one or a combination of more of activated carbon, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanofibers, carbon paper, graphene sheets and carbon cloth.

7. The method for preparing a zinc anode modified by a metal complex according to claim 1, wherein the method comprises the following steps: the carbon source in the zinc/carbon composite material is set as one or more of activated carbon, carbon nanofibers and graphene sheets.

8. Use of a method of preparing a metal complex modified zinc negative electrode according to any one of claims 1 to 7 in an aqueous zinc-based battery.

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