Three-dimensional ordered macroporous metal oxide air electrode, preparation method thereof and zinc-air battery

Abstract

The invention provides a self-supporting three-dimensional ordered macroporous metal oxide air electrode, a preparation method of the self-supporting three-dimensional ordered macroporous metal oxide air electrode and application of the self-supporting three-dimensional ordered macroporous metal oxide air electrode to a zinc-air battery, and belongs to the field of zinc-air battery and nano material preparation. By constructing a three-dimensional ordered macroporous microstructure, the mass transfer capacity of the metal oxide air electrode is improved, the high porosity can provide an efficient transmission channel for rapid transmission of gas and liquid, the high specific surface area can provide a gas-liquid-solid three-phase reaction area, the number of effective catalytic active sites is increased, electron transfer is promoted, and the catalytic activity of the metal oxide air electrode is improved. And the zinc-air battery with long service life and high performance can be realized. The preparation of the three-dimensional ordered macroporous metal oxide air electrode is easy to realize, the universality is realized, and the process is simple. The preparation method is suitable for preparing different materials, and the structural material has important application prospects in the fields of metal-air batteries, fuel cells, electrolyzed water and the like.

Description

Technical Field

[0001] The invention belongs to the field of zinc-air battery and nano material preparation, and specifically relates to a self-supporting three-dimensional ordered macroporous metal oxide air electrode and a preparation method thereof and zinc-air battery application. Background Art

[0002] Due to the excessive consumption of fossil fuels, the greenhouse effect and environmental pollution, there is an urgent need to develop a new energy system with high efficiency and low cost. Zinc-air batteries use aqueous electrolytes, have no risk of spontaneous combustion and are highly safe. They have high energy density, long service life, strong environmental adaptability, high element abundance, low cost, easy recycling, and are green and environmentally friendly. They are a green, low-carbon new energy system with broad application prospects and have become a hot topic in current research.

[0003] At present, the performance of zinc-air batteries, such as energy density, energy efficiency, and service life, is mainly restricted by the charge and discharge process on the air cathode side, namely, oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The low catalytic activity and stability of the cathode electrocatalyst for ORR / OER largely affect the power density, energy efficiency, and cycle life of zinc-air batteries in practical applications. Transition metal oxides have excellent intrinsic ORR / OER electrocatalytic performance, high charge transfer rate, and good stability in alkaline media. They are low-cost and easy to prepare, and are ideal ORR / OER electrocatalysts. The ORR / OER reaction of zinc-air batteries involves a gas-liquid-solid three-phase interface, and the void structure of the air electrode has an important influence on the mass transfer efficiency and battery performance. The three-dimensional ordered macroporous (3DOM) structure has excellent mass transfer capacity. Its high porosity can provide an efficient transmission channel for the rapid transmission of gas and liquid; the high specific surface area can provide a gas-liquid-solid three-phase reaction area, increase the number of effective catalytic active sites, and promote electron transfer.

[0004] Therefore, the development of three-dimensional ordered macroporous metal oxide air electrodes has important application value for improving the performance of zinc-air batteries. The preparation method of 3DOM metal oxides is mainly through the colloidal microsphere hard template method. However, during the self-assembly process of the colloidal microsphere opal template and the infiltration process of the precursor solution, the tensile stress and capillary force caused by the evaporation and drying of the solvent or the subsequent calcination usually form large-scale structural defects and cracks, which will seriously hinder the electron transfer and lead to battery performance loss. In addition, the current air electrodes based on 3DOM metal oxides are mainly prepared by synthesizing metal oxide catalyst powders with three-dimensional macroporous structures and preparing membrane electrodes with the assistance of binders and conductive additives. There are bottleneck problems such as poor mechanical stability and easy blockage of catalytic active sites. Summary of the invention

[0005] The present invention is made to solve the above problems, and aims to provide a self-supporting binder-free three-dimensional ordered macroporous metal oxide air electrode and a preparation method thereof and zinc-air battery application.

[0006] The present invention provides a universal preparation method for a three-dimensional ordered macroporous metal oxide air electrode, which has the following characteristics and comprises the following steps: S10, using a substrate-loaded microsphere orderly stacked opal structure as a template, wherein the microsphere comprises any one or more of polymethyl methacrylate microspheres, polystyrene microspheres, silica microspheres, polylactic acid microspheres or chitosan microspheres; S20, immersing the template in a precursor solution containing metal ions and a chelating agent to obtain an intermediate product, wherein the chelating agent comprises any one or more of monosaccharides, disaccharides or polysaccharides; S30, separating and drying the intermediate product and then calcining it to obtain a substrate-loaded three-dimensional ordered macroporous metal oxide air electrode.

[0007] The method for preparing the three-dimensional ordered macroporous metal oxide air electrode provided by the present invention may also have the following characteristics: wherein, in step S10, the size of the microspheres is uniform.

[0008] In the preparation method of the three-dimensional ordered macroporous metal oxide air electrode provided by the present invention, it can also have the following characteristics: wherein, in step S10, the substrate includes any one or more of carbon cloth, stainless steel mesh, copper mesh, nickel mesh, FTO glass, ITO glass, Ti sheet or Si sheet.

[0009] In the preparation method of the three-dimensional ordered macroporous metal oxide air electrode provided by the present invention, it can also have the following characteristics: wherein, in step S20, the metal corresponding to the metal ion includes any one or more of Mn, Fe, Zn, Co, Ru, Mo, Al, W, Ni or Ti, the chelating agent includes sucrose and / or glucose, and the solvent of the precursor solution includes any one or more of deionized water, ethanol or methanol.

[0010] The method for preparing the three-dimensional ordered macroporous metal oxide air electrode provided by the present invention may also have the following characteristics: wherein, in the precursor solution of step S20: the concentration of metal ions is 0.5 mol / L to 1 mol / L, and the concentration of chelating agent is 0.05 mol / L to 0.1 mol / L.

[0011] The method for preparing the three-dimensional ordered macroporous metal oxide air electrode provided by the present invention may also have the following characteristics: wherein, in step S20, the template immersion time is 10 min to 30 min.

[0012] In the preparation method of the three-dimensional ordered macroporous metal oxide air electrode provided by the present invention, it can also have the following characteristics: wherein, in step S30, the drying method is heating at 70°C to 100°C for 2h to 5h, and the calcination method is: in an air atmosphere, heating to 400°C to 500°C in a tubular furnace at a heating rate of 2°C / min to 10°C / min and calcining for 2h.

[0013] The present invention also provides a three-dimensional ordered macroporous metal oxide air electrode having the following characteristics: the electrode is prepared by any one of the above-mentioned methods for preparing a three-dimensional ordered macroporous metal oxide air electrode.

[0014] The three-dimensional ordered macroporous metal oxide air electrode provided by the present invention may also have the following characteristics: wherein the three-dimensional ordered macroporous metal oxide air electrode serves as an air electrode without a binder.

[0015] The present invention also provides a rechargeable zinc-air battery application having the following characteristics, including: an electrolyte, including an alkaline electrolyte and an additive, the alkaline electrolyte including NaOH (aq) and / or KOH (aq), and the additive including zinc acetate (aq) and vanillin (aq); an air cathode, which is a three-dimensional ordered macroporous metal oxide air electrode according to claim 8 or 9; and a zinc anode, which is arranged opposite to the air cathode and separated by a diaphragm.

[0016] Functions and Effects of the Invention

[0017] The present invention provides a general preparation method for a self-supporting three-dimensional ordered macroporous metal oxide air electrode. The method is applicable to the preparation of different materials, and the structural material has important application prospects in the fields of metal-air batteries, fuel cells and water electrolysis. The preparation method is universal and the process is simple.

[0018] The present invention improves the mass transfer capacity of the metal oxide air electrode by constructing a three-dimensional ordered macroporous microstructure. The high porosity can provide an efficient transmission channel for the rapid transmission of gas and liquid. The high specific surface area can provide a gas-liquid-solid three-phase reaction area, increase the number of effective catalytic active sites, promote electron transfer, and realize a long-life, high-performance zinc-air battery. The present invention is easy to realize the preparation of the three-dimensional ordered macroporous metal oxide air electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flowchart of a method for preparing a three-dimensional ordered macroporous metal oxide air electrode according to an embodiment of the present invention;

[0020] Figure 2 is an electron microscope picture of a polystyrene microsphere template of an embodiment of the present invention;

[0021] Figure 3 is a cross-sectional electron microscope picture of a polystyrene microsphere template of an embodiment of the present invention;

[0022] Figure 4 This is an electron microscope image of the three-dimensional ordered macroporous structure of Fe2O3 during the preparation process of the electrode 1 of the embodiment of the present invention;

[0023] Figure 5 The three-dimensional ordered macroporous structure RuCoO in the preparation process of the electrode 2 of the embodiment of the present invention x Electron microscope images of

[0024] Figure 6 The three-dimensional ordered macroporous structure WCoFeNiZnMnRuO in the preparation process of the electrode 3 of the embodiment of the present invention is x Electron microscope images of

[0025] Figure 7 is a bifunctional LSV curve of the electrode 2 of the embodiment of the present invention;

[0026] Figure 8 1 is a charge and discharge polarization curve and a power density curve of a zinc-air battery of an embodiment of the present invention;

[0027] Fig. 9 The zinc-air battery of the embodiment of the present invention is 5mA / cm 2 The discharge capacity curve below:

[0028] Fig.10 The zinc-air battery of the embodiment of the present invention is 5mA / cm 2 Constant current charge and discharge cycle curve under ;

[0029] Fig.11 The zinc-air battery of the embodiment of the present invention is 5 / 50mA / cm 2 Fast charging cycle curve below. DETAILED DESCRIPTION

[0030] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the following examples and drawings specifically describe a three-dimensional ordered macroporous metal oxide air electrode and its preparation method and a zinc-air battery of the present invention.

[0031] <Example>

[0032] Figure 1 It is a flowchart of a method for preparing a three-dimensional ordered macroporous metal oxide air electrode according to an embodiment of the present invention.

[0033] like Figure 1As shown, this embodiment provides a method for preparing a three-dimensional ordered macroporous metal oxide air electrode, comprising the following steps:

[0034] S10, opal structure stacked with carbon cloth-supported polystyrene microspheres as template.

[0035] The method for preparing the template comprises the following steps:

[0036] S11, adding 1500 μL of 10 wt% polystyrene suspension of uniform size into 5 mL of deionized water, and then adding 100 μL of ethylene glycol, and ultrasonicating for 15 minutes to form a polystyrene microsphere suspension.

[0037] S12, immersing the carbon cloth in a polystyrene microsphere suspension at 65° C. and 70% humidity for 720 min, and self-assembling to obtain an opal structure template of carbon cloth-loaded polystyrene microspheres.

[0038] Figure 2 is an electron microscope picture of a polystyrene microsphere template of an embodiment of the present invention; Figure 3 is a cross-sectional electron microscope picture of a polystyrene microsphere template according to an embodiment of the present invention.

[0039] like Figure 2 and Figure 3 As shown, the polystyrene microsphere template prepared by the present invention is in a hexagonal close-packed state, is evenly and orderly arranged over a large area, has no large cracks or defects, and has a thickness of up to 35.18 μm.

[0040] S20, immersing the template in a precursor solution containing metal ions and a chelating agent to obtain an intermediate product, comprising the following sub-steps:

[0041] S21, adding metal ions and chelating agents into a solvent, and mixing them evenly with magnetic stirring, wherein the metal corresponding to the metal ions includes any one or more of Mn, Fe, Zn, Co, Ru, Mo, Al, W, Ni or Ti, with a concentration of 0.5 mol / L to 1 mol / L, the chelating agent includes sucrose and / or glucose, with a concentration of 0.05 mol / L to 0.1 mol / L, and the solvent includes any one or more of deionized water, ethanol or methanol

[0042] S22, adding concentrated sulfuric acid to adjust the pH, stirring for 2 min to obtain a precursor solution;

[0043] S23, soaking the template in the precursor solution for 15 minutes to obtain an intermediate product.

[0044] S30, separating and drying the intermediate product and then calcining it to obtain a three-dimensional macroporous metal oxide, comprising the following sub-steps:

[0045] S31, separating the intermediate product and drying it at 70°C for 30 min;

[0046] S32, calcining the dried intermediate product at 100°C for 5h in an air atmosphere, and then calcining at 400°C for 2h at a heating rate of 2°C / min to obtain a three-dimensional ordered macroporous metal oxide air electrode supported by carbon cloth.

[0047] This embodiment also provides a three-dimensional ordered macroporous metal oxide air electrode, which is prepared according to the above steps, and there are three parts in total, which are respectively recorded as electrode 1, electrode 2 and electrode 3.

[0048] The specific parameters of the electrode 1, the electrode 2 and the electrode 3 during the preparation process are shown in Table 1.

[0049] Table 1 (Specific parameters of electrode 1, electrode 2 and electrode 3 during the preparation process)

[0050]

[0051] Figure 4 This is an electron microscope image of the three-dimensional ordered macroporous structure of Fe2O3 during the preparation process of the electrode 1 of the embodiment of the present invention; Figure 5 The three-dimensional ordered macroporous structure RuCoO in the preparation process of the electrode 2 of the embodiment of the present invention x Electron microscope images of Figure 6 The three-dimensional ordered macroporous structure WCoFeNiZnMnRuO in the preparation process of the electrode 3 of the embodiment of the present invention is x Electron microscope image of .

[0052] like Figures 4 to 6 As shown, the Fe2O3 (electrode 1) and RuCoO prepared in this embodiment x (Electrode 2), WCoFeNiZnMnRuO x (Electrode 3) presents a high-quality three-dimensional ordered macroporous structure over a large area, the pores are uniform and ordered, defects and cracks are basically avoided, and a three-dimensional long-range ordered multi-layer pore interconnected structure can be observed.

[0053] Figure 7 : is the bifunctional LSV curve of the electrode 2 according to the embodiment of the present invention.

[0054] like Figure 7 As shown, the electrode 2 (three-dimensional ordered macroporous structure RuCoO x The air electrode exhibits excellent bifunctional oxygen electrocatalytic activity, with an oxygen evolution reaction overpotential (E) as low as 192 mV. 10 =1.422V) and the high half-wave potential of oxygen reduction reaction: E 1 / 2=0.824V, making the potential difference (ΔE=E 10 -E 1 / 2 ) as low as 0.598V.

[0055] This embodiment also provides a zinc-air battery, which uses the electrode 2 (three-dimensional ordered macroporous structure RuCoO x ) as the air cathode.

[0056] The zinc-air battery in this embodiment includes a zinc anode, an air cathode, a separator and an electrolyte.

[0057] The zinc anode (zinc foil) and the air cathode (electrode 2 in this embodiment) are arranged opposite to each other and separated by a diaphragm.

[0058] The electrolyte includes an alkaline electrolyte and an additive, the alkaline electrolyte includes NaOH (aq) and / or KOH (aq), and the additive includes zinc acetate (aq) and vanillin (aq).

[0059] Figure 8 1 is the charge and discharge polarization curve and power density curve of the zinc-air battery of the embodiment of the present invention.

[0060] like Figure 8 As shown, during the discharge process, based on the three-dimensional ordered macroporous RuCoO x Zinc-air batteries (RuCoO x The peak power density of the base battery is 215mW / cm 2 , better than Pt / C+RuO2(188.7mW / cm 2 ).

[0061] Fig. 9 The zinc-air battery of the embodiment of the present invention is 5mA / cm 2 The discharge capacity curve below.

[0062] like Fig. 9 As shown, RuCoO x Base cell at 5mA / cm 2 The specific capacity is 694.77 mAh / g Zn , can be continuously and stably discharged at 1.2V for 125h. RuCoO x The specific capacity of the base battery has reached the same level as Pt / C+RuO2 (700.3mAh / g Zn ) level, showing that RuCoO x Excellent discharge stability of aqueous zinc-air batteries.

[0063] Fig.10 The zinc-air battery of the embodiment of the present invention is 5mA / cm 2Constant current charge and discharge cycle curve under ; Fig.11 The zinc-air battery of the embodiment of the present invention is 5 / 50mA / cm 2 Fast charging cycle curve below.

[0064] like Fig.10 and 11 As shown, RuCoO x The base battery exhibits excellent charge-discharge performance and cycle stability, and the charge-discharge voltage difference is very small after long-term operation. 2 When discharging at low voltage, the charge and discharge energy efficiency can reach 69.50%, and the service life exceeds 590h, which is significantly better than Pt / C+RuO2. The fast charge cycle can even stably reach 1380h at a charging potential of only 2.48V, and there is almost no efficiency decay after a long period of charge and discharge.

[0065] Functions and Effects of the Embodiments

[0066] The preparation method of the self-supporting three-dimensional ordered macroporous metal oxide air electrode of this embodiment uses the substrate-loaded microsphere orderly stacked opal structure as a template, and immerses the opal template in a precursor solution containing metal ions and a chelating agent. The chelating agent chelates the metal ions in the precursor solution so that they are evenly infiltrated in the template. During the calcination process, the chelating agent optimizes the oxidation temperature of the metal precursor and the decomposition temperature of the template, and can form a stable metal oxide network before the template collapses, ensuring a perfect three-dimensional macroporous structure. With the help of the confining effect of the chelating agent and the microsphere template, a large area of ​​uniform and crack-free three-dimensional ordered macroporous metal oxide can be obtained after low-temperature calcination. The present invention is simple to operate and has universal applicability, and can be used for the preparation of more than 20 kinds of one-element and multi-element three-dimensional ordered macroporous metal oxide air electrodes. The air electrode has a wide range of application potential in the field of zinc-air batteries.

[0067] The chelating agent in this embodiment chelates the metal ions in the precursor solution, making them uniformly infiltrated and dispersed in the template, effectively preventing the metal particles from agglomerating;

[0068] In this embodiment, during the calcination process, the chelating agent optimizes the oxidation temperature of the metal precursor and the decomposition temperature of the template, and can form a stable metal oxide network before the template collapses, ensuring a perfect three-dimensional macroporous structure.

[0069] The chelating agent in this embodiment can be used as a secondary template for the generation of mesopores, providing greater porosity and higher specific surface area;

[0070] The metal oxide air electrode with a three-dimensional ordered macroporous structure in this embodiment can achieve rapid mass transfer and fully expose effective catalytic active sites, thereby achieving excellent ORR / OER catalytic performance.

[0071] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a three-dimensional ordered macroporous metal oxide air electrode, characterized in that: The following steps are involved: S10, using the substrate-loaded microspheres in an orderly stacked opal structure as a template, wherein the microspheres include any one or more of polymethyl methacrylate microspheres, polystyrene microspheres, silica microspheres, polylactic acid microspheres or chitosan microspheres; S20, immersing the template in a precursor solution containing metal ions and a chelating agent to obtain an intermediate product, wherein the chelating agent includes any one or more of monosaccharides, disaccharides or polysaccharides; S30, separating, drying and calcining the intermediate product to obtain the substrate-supported three-dimensional ordered macroporous metal oxide air electrode.

2. The method for preparing a three-dimensional ordered macroporous metal oxide air electrode according to claim 1, characterized in that: in, In step S10, the microspheres have uniform sizes.

3. The method for preparing a three-dimensional ordered macroporous metal oxide air electrode according to claim 1, characterized in that: in, In step S10, the substrate includes any one or more of carbon cloth, stainless steel mesh, copper mesh, nickel mesh, FTO glass, ITO glass, Ti sheet or Si sheet.

4. The method for preparing a three-dimensional ordered macroporous metal oxide air electrode according to claim 1, characterized in that: in, In step S20, the metal corresponding to the metal ion includes any one or more of Mn, Fe, Zn, Co, Ru, Mo, Al, W, Ni or Ti. The chelating agent includes sucrose and / or glucose, The solvent of the precursor solution includes any one or more of deionized water, ethanol or methanol.

5. The method for preparing a three-dimensional ordered macroporous metal oxide air electrode according to claim 1, characterized in that: in, In the precursor solution of step S20: The concentration of the metal ion is 0.5 mol / L to 1 mol / L, The concentration of the chelating agent is 0.05 mol / L to 0.1 mol / L.

6. The method for preparing a three-dimensional ordered macroporous metal oxide air electrode according to claim 1, characterized in that: in, In step S20, the template is immersed for 10 minutes to 30 minutes.

7. The method for preparing a three-dimensional ordered macroporous metal oxide air electrode according to claim 1, characterized in that: in, In step S30, the drying method is heating at 70°C to 100°C for 2h to 5h. The calcination method is: in an air atmosphere, heating in a tube furnace at a heating rate of 2°C / min to 10°C / min to 400°C to 500°C and calcining for 2h.

8. A three-dimensional ordered macroporous metal oxide air electrode, characterized in that: The three-dimensional ordered macroporous metal oxide air electrode is prepared by the preparation method of any one of claims 1 to 7.

9. The three-dimensional ordered macroporous metal oxide air electrode according to claim 8, characterized in that: in, The three-dimensional ordered macroporous metal oxide air electrode serves as an air electrode without a binder.

10. A zinc-air battery, characterized in that: include: An electrolyte comprising an alkaline electrolyte and an additive, wherein the alkaline electrolyte comprises NaOH (aq) and / or KOH (aq), and the additive comprises zinc acetate (aq) and vanillin (aq); An air cathode, which is the three-dimensional ordered macroporous metal oxide air electrode according to claim 8 or 9; and The zinc anode is arranged opposite to the air cathode and the two are separated by a diaphragm.

Images