Zinc negative electrode plate with carbon network skeleton, preparation method of zinc negative electrode plate and aqueous zinc-manganese battery

Abstract

The invention provides a zinc negative plate with a carbon network skeleton, a preparation method of the zinc negative plate and an aqueous zinc-manganese battery. The zinc negative plate with the carbon network skeleton comprises a zinc foil substrate, a binder and the carbon network skeleton rolled on the zinc foil substrate. A carbon network skeleton is used as a zinc deposition carrier, and an electrolyte additive is combined, so that the deep cycle performance of the aqueous zinc-manganese battery is optimized. The zinc negative electrode with the carbon fiber network skeleton has relatively strong hydrophilic and hydrophobic properties and moderate zinc affinity to guide high-speed diffusion of zinc ions and effectively inhibit hydrogen evolution side reaction; the three-dimensional carbon network has a large reaction specific surface area and is beneficial to uniform deposition of zinc, and meanwhile, the zinc foil is used as a zinc source to supplement zinc ions in circulation; and the Ce < 3 + > additive and Zn < 2 + > are competitively adsorbed to form a dynamic electrostatic shielding layer, so that uniform zinc deposition is induced. The zinc negative electrode modification and additive strategy has wide application potential in the fields of aqueous zinc ion batteries, zinc-air batteries, zinc-based flow batteries and the like.

Description

Technical Field

[0001] The present invention relates to the field of aqueous zinc-based batteries, and particularly to a zinc negative electrode sheet with a carbon network skeleton, a preparation method thereof, and an aqueous zinc-manganese battery. Background Art

[0002] Traditional fossil energy systems are represented by coal, oil, and natural gas. The total amount of such energy resources is limited and they are non-renewable resources, and the resource extraction costs and difficulties are constantly rising. In addition, during the extraction and use of fossil energy, serious environmental pollution and greenhouse gas emissions and other problems are also caused. Therefore, the development of efficient, safe, low-carbon, and clean renewable energy is of great significance for realizing sustainable social development. Clean energy sources from nature such as wind energy, solar energy, tidal energy, and geothermal energy have deficiencies such as relatively scattered distribution, high development and utilization costs, and unstable energy supply. In order to use these clean energies more efficiently, it is necessary to combine them with an efficient and safe energy storage and conversion system.

[0003] Lithium-ion batteries have many advantages such as high power density, low self-discharge rate, and lightweight devices, thus triggering an energy revolution in the fields of mobile electronic devices and electric vehicles. At present, lithium-ion batteries are still restricted by some factors, such as relatively low specific capacity, poor cycle stability, and extremely poor low-temperature adaptability. More seriously, due to the extreme sensitivity of alkali lithium metals to water and air, lithium batteries usually use organic electrolytes, resulting in the risk of fire or even explosion when the battery is overcharged or discharged, encounters collisions, or is in a high-temperature environment.

[0004] Aqueous secondary batteries use aqueous solutions of acids, alkalis, or metal salts as electrolytes, and the safety is significantly improved. Moreover, the cost of aqueous electrolytes is low, which is conducive to their large-scale application. In the aqueous battery system, zinc-based secondary batteries based on zinc metal negative electrodes have advantages such as high abundance of zinc metal resources, intrinsic safety, long cycle life, low cost, and high specific capacity. Aqueous zinc-manganese batteries generate current based on the redox reaction occurring between the Zn 2+ / Zn redox pair on the negative electrode side, and the Zn 2+ storage mechanism of the manganese dioxide positive electrode mainly includes Zn 2+ insertion / extraction mechanism, Zn 2+ / H + co-insertion / extraction mechanism, conversion reaction mechanism, dissolution / deposition mechanism, mixed reaction mechanism, etc.

[0005] During the charge / discharge cycle of the battery, the zinc anode is affected by factors such as dendrite growth, hydrogen evolution side reaction, surface passivation and corrosion, resulting in a decrease in the energy efficiency and working life of the battery. During zinc deposition, the uneven local current distribution will accelerate the formation and growth of zinc dendrites, and finally the zinc dendrites will pierce through the separator and contact the battery cathode, leading to a short circuit of the battery. The hydrogen evolution side reaction on the anode surface will cause continuous electrolyte loss, and a large amount of irreversible by-products will adhere to the anode surface. Common strategies for stabilizing zinc metal anodes include electrode structure design, electrode interface optimization, electrolyte optimization and separator design. Through the structured design of the electrode, the specific surface area at the zinc anode interface can be effectively increased, the local current density can be reduced, and dendrite growth can be alleviated. However, a larger reaction specific surface area is usually accompanied by serious side reactions, so it is necessary to suppress side reactions through interface optimization, such as regulating hydrophilic and hydrophobic properties and constructing an electrostatic shielding layer. In order to achieve stable long-term zinc deposition / stripping cycling, effective regulation is still required in the control of the deposition crystal plane orientation. Compared with the common (101)-textured Zn, Zn with a texture mainly composed of (002) planes has the ability to inhibit side reactions and dendrite growth. CN108520985B discloses a method for improving the cycle life of a zinc battery and its application. However, the porous coating only increases the specific surface area and cannot provide side reaction inhibition and deposition guiding effects, which is not conducive to long-term deep cycling of zinc. CN110416549B discloses a metal zinc anode with a uniform mesoporous structure coating, its preparation method and application, and it is also difficult to achieve stable cycling at depth.

[0006] Therefore, it is of practical significance to develop a zinc anode with deep deposition / stripping cycling performance to improve the long-term cycle life of aqueous zinc-manganese batteries. Summary of the Invention

[0007] The present invention is made to solve the above problems, and the purpose is to provide a zinc anode sheet with a carbon network skeleton, a preparation method thereof, and an aqueous zinc-manganese battery.

[0008] The present invention provides a zinc anode sheet with a carbon network skeleton, having the following characteristics, including: a zinc foil substrate, a binder, and a carbon network skeleton roll-pressed on the zinc foil substrate, wherein the binder is arranged between the zinc foil substrate and the carbon network skeleton.

[0009] In the zinc anode sheet with a carbon network skeleton provided by the present invention, it may also have the following characteristics: wherein, the carbon network skeleton is any one or more of carbon fiber felt, carbon fiber cloth, and carbon foam, the thickness of the carbon network skeleton is 100-3000 nm, and the carbon network skeleton is surface-treated by oxygen plasma.

[0010] In the zinc negative electrode sheet with a carbon network skeleton provided by the present invention, it may also have the following characteristics: among them, the binder is any one or more of perfluorosulfonic acid, polyvinylidene fluoride, and polytetrafluoroethylene.

[0011] The present invention also provides a preparation method of the above-mentioned zinc negative electrode sheet with a carbon network skeleton, which has the following characteristics and includes the following steps: Step 1, perform oxygen plasma surface treatment on the carbon network skeleton; Step 2, perform polishing treatment on the surface of the zinc foil; Step 3, drop a binder solution on the polished zinc foil surface; Step 4, attach the surface-treated carbon network skeleton to the polished zinc foil and roll them into one body. Among them, in Step 3, the binder solution includes a binder and ethanol.

[0012] In the preparation method of the zinc negative electrode sheet with a carbon network skeleton provided by the present invention, it may also have the following characteristics: among them, in Step 3, the volume ratio of the binder to ethanol is 1:(1 - 3).

[0013] In the preparation method of the zinc negative electrode sheet with a carbon network skeleton provided by the present invention, it may also have the following characteristics: among them, in Step 4, when performing rolling, the rolling spacing is 0.5 - 1.5 mm.

[0014] The present invention also provides an aqueous zinc-manganese battery, which has the following characteristics and includes: a positive electrode current collector, a zinc negative electrode sheet, a separator, and an electrolyte. Among them, the zinc negative electrode sheet is the above-mentioned zinc negative electrode sheet with a carbon network skeleton.

[0015] In the aqueous zinc-manganese battery provided by the present invention, it may also have the following characteristics: among them, the zinc negative electrode sheet and the positive electrode current collector are arranged oppositely, and the two are separated by a separator. The side of the zinc negative electrode sheet with the carbon network skeleton faces the separator.

[0016] In the aqueous zinc-manganese battery provided by the present invention, it may also have the following characteristics: among them, the material of the positive electrode current collector is carbon fiber felt, the separator is glass fiber, and the electrolyte includes a zinc ion electrolyte, a manganese ion electrolyte, and an electrolyte additive.

[0017] In the aqueous zinc-manganese battery provided by the present invention, it may also have the following characteristics: among them, the zinc ion electrolyte is any one of an aqueous solution of zinc sulfate, an aqueous solution of zinc trifluoromethanesulfonate, and an aqueous solution of zinc chloride, the manganese ion electrolyte is an aqueous solution of manganese sulfate, the electrolyte additive is cerium chloride, and the concentrations of the zinc ion electrolyte, the manganese ion electrolyte, and the electrolyte additive in the electrolyte are 1M, 1M, and 2 g / L respectively. -1 .

[0018] Functions and effects of the invention

[0019] The zinc negative electrode sheet with a carbon network skeleton, its preparation method, and the aqueous zinc-manganese battery according to the present invention. Since the zinc negative electrode sheet with a carbon network skeleton includes a zinc foil substrate, a binder, and a carbon network skeleton roll-pressed on the zinc foil substrate, the carbon network skeleton has high zinc affinity and strong hydrophobic characteristics, which can effectively regulate the zinc deposition behavior and reduce the generation of hydrogen evolution side reactions. Moreover, the three-dimensional carbon network of the carbon network skeleton has a large reaction specific surface area, which is conducive to the uniform deposition of zinc. At the same time, the zinc foil substrate serves as a zinc source to supplement zinc ions during cycling.

[0020] Furthermore, since the electrolyte of the aqueous zinc-manganese battery contains a Ce 3+ additive, the Ce 3+ additive and Zn 2+ compete for adsorption to form a dynamic electrostatic shielding layer, thereby inducing uniform zinc deposition.

[0021] Therefore, the zinc negative electrode sheet with a carbon network skeleton of the present invention has deep deposition / stripping cycle performance, and the aqueous zinc-manganese battery of the present invention has a very high long-term cycle life.

[0022] In addition, the process of the present invention is simple, has universality, and is easy to realize the preparation of high-performance zinc negative electrodes with large areas, thereby realizing long-life aqueous zinc-manganese batteries.

[0023] Meanwhile, the zinc negative electrode modification and additive strategy of the present invention have broad application potential in the fields of aqueous zinc-ion batteries, zinc-air batteries, zinc-based flow batteries, zinc-ion capacitors, etc. Description of the Drawings

[0024] Figure 1 is the electron microscope picture of the carbon fiber felt in Example 1 of the present invention;

[0025] Figure 2 is the cross-sectional electron microscope picture of the zinc foil roll-pressed with the carbon fiber felt in Example 1 of the present invention;

[0026] Figure 3 is the electron microscope picture of the zinc foil roll-pressed with the carbon fiber felt after zinc deposition at 20 mA cm -2 and 10 mAh cm -2 in Example 1 of the present invention;

[0027] Figure 4 is the cycle curve of the zinc foil roll-pressed with the carbon fiber felt, the zinc foil with an NC modification coating, and the zinc foil in the symmetric battery at 20 mA cm -2 and 10 mAh cm -2 in Example 1 of the present invention;

[0028] Figure 5The zinc foils with carbon fiber felt roll-pressed in the symmetric battery, the zinc foils with NC modified coating, and the zinc foils in Example 1 of the present invention at 20 mA cm -2 and 10 mAh cm -2 The electron microscope pictures after 2100 hours of cycling;

[0029] Figure 6 is the cycling performance curve of the aqueous zinc-manganese battery in Example 2 of the present invention at 12 mA cm -2 and 2.5 mAh cm -2 under cycling. Detailed Embodiments

[0030] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the following embodiments will specifically describe the zinc negative electrode sheet with a carbon network skeleton, its preparation method and the aqueous zinc-manganese battery in conjunction with the accompanying drawings.

[0031] Example 1

[0032] This example provides a zinc negative electrode sheet with a carbon network skeleton and its preparation method.

[0033] The preparation method of the zinc negative electrode sheet with a carbon network skeleton includes the following steps:

[0034] Step 1, perform oxygen plasma surface treatment on the carbon network skeleton. The carbon network skeleton is any one or more of carbon fiber felt, carbon fiber cloth, and carbon foam, with a thickness of 100 - 3000 nm. In this example, the carbon network skeleton is a carbon fiber felt with a thickness of 0.5 mm, and its electron microscope picture is as Figure 1 shown.

[0035] Step 2, polish the surface of a commercial zinc foil with a thickness of 0.2 mm using 250 - and 800 - mesh sandpapers respectively to remove the potential oxide layer on the surface of the zinc foil.

[0036] Step 3, drop a binder solution on the polished zinc foil surface. The binder solution includes a binder and ethanol, and the volume ratio of the two is 1:(1 - 3). The binder is any one or more of perfluorosulfonic acid, polyvinylidene fluoride, and polytetrafluoroethylene. In this example, the binder solution is perfluorosulfonic acid (Nafion) and ethanol with a volume ratio of 1:1.

[0037] Step 4, attach the surface - treated carbon fiber felt to the polished zinc foil surface, and send the zinc foil with the attached carbon fiber felt into a roll press to roll them into one body, obtaining a zinc foil with a roll - pressed carbon fiber felt (i.e., the zinc negative electrode sheet with a carbon network skeleton). The roll - pressing spacing is 0.5 - 1.5 mm, and in this example, it is 0.6 mm.

[0038] The zinc negative electrode sheet with a carbon network skeleton includes a zinc foil substrate, a binder, and a carbon network skeleton roll-pressed on the zinc foil substrate. Among them, the binder is disposed between the zinc foil substrate and the carbon network skeleton.

[0039] Figure 3 is the electron microscope picture of the zinc foil roll-pressed with carbon fiber felt after zinc deposition in Example 1 of the present invention at 20 mA cm -2 and 10 mAh cm -2 .

[0040] It can be seen from Figure 3 that zinc can be evenly deposited on the carbon fiber felt.

[0041] Figure 4 are the cyclic voltammetry curves of the zinc foil roll-pressed with carbon fiber felt, the zinc foil with an NC modified coating, and the zinc foil in the symmetric battery in Example 1 of the present invention at 20 mA cm -2 and 10 mAh cm -2 ; Figure 5 are the electron microscope pictures of the zinc foil roll-pressed with carbon fiber felt, the zinc foil with an NC modified coating, and the zinc foil in the symmetric battery in Example 1 of the present invention after cycling for 2100 hours at 20 mA cm -2 and 10 mAh cm -2 ;

[0042] It can be seen from Figure 4 and Figure 5 that in the symmetric battery test, the zinc negative electrode co-regulated by the carbon fiber network and Ce 3+ has a moderate nucleation overpotential (8.1 mV) and the strongest anti-side reaction performance. In the deep cycling test, the zinc symmetric battery achieved an ultra-long cycle life of more than 2100 hours.

[0043] Example 2

[0044] This example provides an aqueous zinc-manganese battery, which includes a positive current collector, a zinc negative electrode sheet, a separator, and an electrolyte.

[0045] Among them, the zinc negative electrode sheet is the zinc foil roll-pressed with carbon fiber felt in Example 1; the positive current collector (positive electrode sheet) is a carbon fiber felt with a thickness of 200 mm; the separator is a glass fiber with a pore diameter of 2.7 μm and a thickness of 675 μm; the electrolyte is an aqueous solution of 1 M ZnSO 4 , 1 M MnSO 4 and 2 g L -1 CeCl 3 .

[0046] The zinc negative electrode sheet and the positive current collector are oppositely arranged, separated by the separator therebetween, and the side of the zinc negative electrode sheet with the carbon network skeleton faces the separator.

[0047] The performance of this aqueous zinc-manganese battery was tested, and the results are as follows:

[0048] Figure 6 This is the cycle performance curve of the aqueous zinc-manganese battery in Example 2 of the present invention at 12 mA cm -2 , 2.5 mAh cm -2 .

[0049] As shown in Figure 6, this aqueous zinc-manganese battery can cycle more than 400 cycles at 12 mA cm -2 and 2.5 mAh cm -2 , and obtain an average Coulombic efficiency of 94% and an energy efficiency of 63%. The zinc anode co-regulated by the carbon fiber network and Ce 3+ significantly reduces the reaction polarization of the aqueous zinc-manganese battery in Example 2 and has the highest reaction kinetics.

[0050] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the claimed present invention. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A zinc negative electrode sheet having a carbon network skeleton, characterized in that: include: A zinc foil substrate, a binder and a carbon network skeleton rolled on the zinc foil substrate, Wherein, the adhesive is arranged between the zinc foil substrate and the carbon network skeleton.

2. The zinc negative electrode sheet with a carbon network skeleton according to claim 1, characterized in that: in, The carbon network skeleton is any one or more of carbon fiber felt, carbon fiber cloth, and carbon foam. The thickness of the carbon network skeleton is 100-3000nm, The carbon network skeleton is surface treated by oxygen plasma.

3. The zinc negative electrode sheet with a carbon network skeleton according to claim 1, characterized in that: in, The binder is any one or more of perfluorosulfonic acid, polyvinylidene fluoride, and polytetrafluoroethylene.

4. The method for preparing a zinc negative electrode sheet having a carbon network skeleton according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1, performing oxygen plasma surface treatment on the carbon network skeleton; Step 2, polishing the surface of the zinc foil; Step 3, adding a binder solution dropwise onto the surface of the polished zinc foil; Step 4, attaching the surface treated carbon network skeleton to the polished zinc foil and rolling them into one body, wherein in step 3, the binder solution includes a binder and ethanol.

5. The zinc negative electrode sheet with a carbon network skeleton according to claim 4, characterized in that: in, In step 3, the volume ratio of the binder to ethanol is 1:(1-3).

6. The zinc negative electrode sheet with a carbon network skeleton according to claim 4, characterized in that: in, In step 4, during the rolling process, the rolling interval is 0.5-1.5 mm.

7. An aqueous zinc-manganese battery, characterized in that: include: Positive electrode current collector, zinc negative electrode sheet, separator and electrolyte, Wherein, the zinc negative electrode sheet is a zinc negative electrode sheet with a carbon network skeleton as described in any one of claims 1 to 3.

8. The aqueous zinc-manganese battery according to claim 7, characterized in that: in, The zinc negative electrode sheet and the positive electrode current collector are arranged opposite to each other and are separated by the separator. The side of the zinc negative electrode sheet having the carbon network skeleton faces the separator.

9. The aqueous zinc-manganese battery according to claim 7, characterized in that: in, The material of the positive electrode current collector is carbon fiber felt, The diaphragm is glass fiber, The electrolyte comprises a zinc ion electrolyte, a manganese ion electrolyte and an electrolyte additive.

10. The aqueous zinc-manganese battery according to claim 9, characterized in that: in, The zinc ion electrolyte is any one of an aqueous solution of zinc sulfate, an aqueous solution of zinc trifluoromethanesulfonate, and an aqueous solution of zinc chloride. The manganese ion electrolyte is an aqueous solution of manganese sulfate, The electrolyte additive is cerium chloride, The concentrations of the zinc ion electrolyte, the manganese ion electrolyte and the electrolyte additive in the electrolyte are 1M, 1M and 2g L -1 .

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