High-performance zinc-air battery positive electrode catalyst based on transition metal, preparation method of high-performance zinc-air battery positive electrode catalyst and zinc-air battery

Abstract

The invention relates to the technical field of electrode materials and electrochemical catalysis, in particular to a high-performance zinc-air battery positive electrode catalyst based on transition metal, a preparation method of the high-performance zinc-air battery positive electrode catalyst based on the transition metal and a zinc-air battery. The metal ions in the formed coordination compound are migrated into the ligand 2-methylimidazole and are self-assembled through the coordination bond to form a new coordination compound, and then the obtained precursor is calcined to form unique morphology and structure, and the obtained positive electrode catalyst is of a hollow porous spherical structure. The spherical surface is rough and has a large number of nano-scale bulges, gaps and pores, so that the spherical surface has the advantage of large specific surface area, and the positive electrode catalyst has excellent catalytic activity and stability. And the method is simple and convenient to control, can be used for industrial large-scale production, and has a wide application prospect in the application field of zinc-air batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode materials and electrochemical catalysis, and in particular to a high-performance zinc-air battery cathode catalyst based on transition metals, a preparation method thereof, and a zinc-air battery. Background Art

[0002] In today's energy sector, with the urgent need for efficient and environmentally friendly energy storage technologies, zinc-air batteries, as a highly promising electrochemical energy storage device, have received widespread attention. Zinc-air batteries offer many significant advantages. Their theoretical energy density is extremely high, reaching 1086Wh / kg, far exceeding that of traditional lithium-ion batteries. This is crucial for meeting the long driving range of electric vehicles and the high energy storage requirements of large-scale energy storage power stations. Furthermore, the raw material cost of zinc-air batteries is relatively low, zinc resources are abundant and their price is relatively stable, and oxygen in the air serves as the positive electrode active material, eliminating the need for additional complex preparation and storage processes. This gives zinc-air batteries significant economic advantages in large-scale applications.

[0003] However, the practical application of zinc-air batteries faces numerous technical challenges, one of the most critical bottlenecks being catalyst performance. During the charge and discharge processes of zinc-air batteries, the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are two crucial electrode reactions. The kinetics of these two reactions are relatively slow, requiring efficient catalysts to reduce the reaction overpotential and increase the reaction rate, thereby improving the overall battery performance, including energy conversion efficiency, charge and discharge speed, and cycling stability.

[0004] Traditional zinc-air battery cathode catalysts are primarily based on precious metal catalysts, such as platinum (Pt)-based catalysts for the oxygen reduction reaction (ORR) and iridium (Ir)-based catalysts for the oxygen evolution reaction (OER). While these precious metal catalysts exhibit excellent catalytic activity, their resource scarcity and high cost significantly limit the large-scale commercial application of zinc-air batteries. To overcome these limitations, researchers have focused on developing high-performance non-precious metal catalysts in recent years. Transition metals possess a rich electronic structure and diverse oxidation states, allowing for the regulation of catalytic reactions by adjusting their composition, structure, and surface properties. For example, some transition metal oxides, sulfides, nitrides, and their composites exhibit catalytic activity and stability comparable to or even superior to precious metal catalysts. Rational design of transition metal-based catalysts can effectively increase the specific surface area of ​​the catalyst, providing more active sites while shortening the diffusion pathways of reactants and accelerating the reaction kinetics.

[0005] However, in the existing technology, the catalytic activity and stability of transition metal-based zinc-air battery cathode catalysts need to be further improved. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the first object of the present invention is to provide a method for preparing a high-performance zinc-air battery cathode catalyst based on a transition metal. The preparation method has the advantages of simplicity, convenient control, and industrial large-scale production. The prepared high-performance zinc-air battery cathode catalyst based on a transition metal has excellent catalytic activity and stability.

[0007] In order to overcome the deficiencies of the prior art, the second object of the present invention is to provide a high-performance transition metal-based zinc-air battery cathode catalyst, which has excellent catalytic activity and stability.

[0008] A third object of the present invention is to provide a zinc-air battery.

[0009] In order to achieve the first object of the above invention, the technical solution adopted by the present invention is as follows:

[0010] The present invention provides a method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst, comprising the following steps:

[0011] S1, dissolving a zinc salt and a cobalt salt in methanol, performing ultrasonic vibration, and then standing at room temperature to form a coordination compound to obtain a first solution;

[0012] S2. Dissolve 2-methylimidazole in methanol and stir at 20° C. to 40° C. to form a ligand dispersion system to obtain a second solution;

[0013] S3, mixing the second solution with the first solution at 20° C. to 40° C., and then standing to age to form a precipitate, and then centrifuging the obtained precipitate, washing, and drying to obtain a precursor;

[0014] S4. calcining the precursor under an inert atmosphere to obtain the high-performance transition metal-based zinc-air battery cathode catalyst.

[0015] The present invention discloses a method for preparing a high-performance zinc-air battery cathode catalyst based on a transition metal. In step S1, a zinc salt and a cobalt salt are first dissolved in methanol. Ultrasonic vibration is used to accelerate the dissolution of the zinc salt and the cobalt salt in the methanol and mix them thoroughly. The metal ions (zinc ions and cobalt ions) are then allowed to stand for a period of time to form a coordination compound with the methanol. The oxygen atom of methanol (CH3OH) has a lone pair of electrons, and the methanol in step S1 serves as a ligand to form a coordination compound with the metal ions. The 2-methylimidazole in step S2 is a ligand for the reaction in step S3. The methanol in step S2 serves as a solvent. In step S2, the ligand 2-methylimidazole is first dissolved in the solvent methanol to form a ligand dispersion system, which facilitates the reaction of preparing a precursor in step S3. In addition, the use of the solvent methanol in step S2 ensures that the metal ions and the ligand 2-methylimidazole are evenly distributed in the solution system in step S3. In addition, in step S3, the ligand 2-methylimidazole will grab the metal ions in the coordination compound formed in step S1 to form a new ligand compound. In step S3, by controlling the mixing temperature of the second solution and the first solution to 20°C to 40°C, the migration of metal ions and the dissolution of microcrystals are moderate, which helps to control the morphology and structure of the precursor, and form an ideal hollow porous spherical structure after calcining the precursor.

[0016] In addition, the present invention first forms a coordination compound with metal ions (zinc ions and cobalt ions) and methanol, and then, in a system using methanol as a solvent, allows the metal ions in the formed coordination compound to migrate to the ligand 2-methylimidazole and self-assemble to form a new coordination compound through coordination bonds, thereby forming a unique precursor morphology and structure. The method of the present invention for preparing a high-performance transition metal-based zinc-air battery cathode catalyst can make the prepared cathode catalyst a hollow porous spherical structure, that is, the sphere has a rough surface and a large number of nano-scale protrusions, gaps and pores, and therefore has the advantage of a large specific surface area, thereby making the cathode catalyst have excellent catalytic activity and stability.

[0017] Furthermore, in step S1, the zinc salt and the cobalt salt are zinc sulfate heptahydrate and cobalt sulfate heptahydrate, respectively; and / or

[0018] The molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:(1-4); and / or

[0019] The molar volume ratio of the zinc salt to methanol is 1 mol: (50-150) mL.

[0020] Furthermore, in step S1, the ultrasonic oscillation time is 3 min to 5 min; this ultrasonic oscillation time helps to evenly disperse the zinc ions and cobalt ions in the system, which is beneficial to the subsequent formation of a uniform coordination compound.

[0021] The standing time at room temperature is 1 to 5 hours, which allows the zinc ions, cobalt ions and the ligand methanol to fully form a coordination compound.

[0022] Furthermore, in step S2, the mass ratio of 2-methylimidazole to methanol is (0.01-0.1):1; and / or

[0023] The stirring time is 1 h to 5 h.

[0024] Furthermore, in step S3, the mass ratio of the first solution to the second solution is 1:(1-1.5); and / or

[0025] The standing time is 8 hours to 24 hours, which allows the metal ions to fully migrate into the ligand 2-methylimidazole and self-assemble to form a new coordination compound through coordination bonds.

[0026] Furthermore, in step S3, the washing is performed 3 to 6 times with methanol. The use of methanol for washing can effectively remove impurities without destroying the structure of the precursor. Moreover, methanol has a low boiling point and is easily volatile, which is also beneficial for subsequent drying.

[0027] The drying temperature is 78° C. to 82° C., and the drying time is 8 to 10 hours. Drying first is beneficial for subsequent calcination and helps form a cathode catalyst structure with a unique morphology.

[0028] Furthermore, in step S4, the inert atmosphere is an argon atmosphere or a nitrogen atmosphere.

[0029] Furthermore, in step S4, the calcination temperature is 600° C. to 1200° C., and the calcination time is 1 hour to 5 hours.

[0030] In order to achieve the second purpose of the above invention, the technical solution adopted by the present invention is as follows:

[0031] The present invention provides a high-performance transition metal-based zinc-air battery cathode catalyst, which is prepared by the above-mentioned method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst.

[0032] In order to achieve the third purpose of the above invention, the technical solution adopted by the present invention is as follows:

[0033] The present invention provides a zinc-air battery, comprising the above-mentioned high-performance zinc-air battery cathode catalyst based on transition metals.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention provides a method for preparing a high-performance zinc-air battery cathode catalyst based on a transition metal, wherein metal ions (zinc ions and cobalt ions) are first formed into a coordination compound with methanol, and then, in a system where methanol is used as a solvent, the metal ions in the coordination compound with methanol as a ligand are transferred to the ligand 2-methylimidazole to form a new coordination compound through self-assembly through coordination bonds, and the obtained precursor is calcined to form a unique morphology and structure. The method of the present invention for preparing a high-performance zinc-air battery cathode catalyst based on a transition metal can make the prepared cathode catalyst a hollow porous spherical structure, that is, the surface of the sphere is rough and has a large number of nano-scale protrusions, gaps and pores, so it has the advantage of a large specific surface area, thereby making the cathode catalyst have excellent catalytic activity and stability.

[0036] (2) The present invention provides a method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst, which is simple, easy to control, and can be used for industrial large-scale production.

[0037] (3) The present invention provides a high-performance transition metal-based zinc-air battery cathode catalyst with excellent catalytic activity and stability, and low preparation cost. Furthermore, the catalyst exhibits performance comparable to, and even partially surpasses, precious metals in oxygen reduction reactions, oxygen evolution reactions, and zinc-air batteries, and has broad application prospects in the field of zinc-air batteries.

[0038] (4) The zinc-air battery of the present invention uses a high-performance zinc-air battery cathode catalyst based on a transition metal prepared by the present invention, thereby making the reaction overpotential low and the reaction rate fast, thereby improving the energy conversion efficiency, charge and discharge speed and cycle stability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 This is a SEM image of a high-performance transition metal-based zinc-air battery cathode catalyst prepared in Example 1 of the present invention.

[0041] Figure 2 This is a SEM image at another magnification of a high-performance transition metal-based zinc-air battery cathode catalyst prepared in Example 1 of the present invention.

[0042] Figure 33 and 4. It is the XRD diagram of the cathode catalysts of Examples 1 to 4, Comparative Examples 1 and 2 of the present invention.

[0043] Figure 4 1 and 2 are LSV curves of the oxygen reduction reaction of the cathode catalysts of Examples 1 to 4 of the present invention, Comparative Examples 1 and 2, and a commercial Pt / C catalyst.

[0044] Figure 5 3 and 4, and the histograms of the half-wave potential and limiting current density of the positive electrode catalysts of Examples 1 to 4 of the present invention, Comparative Examples 1 and 2, and the commercial Pt / C catalyst for the oxygen reduction reaction.

[0045] Figure 6 1 and 2 are LSV curves of the oxygen evolution reaction of the positive electrode catalysts of Examples 1 to 4 of the present invention, Comparative Examples 1 and 2, and a commercial RuO2 catalyst.

[0046] Figure 7 The positive electrode catalysts of Examples 1 to 4, Comparative Examples 1 and 2 of the present invention, and the commercial RuO2 catalyst at 10 mA·cm -2 Comparison of OER overpotentials under different conditions. DETAILED DESCRIPTION

[0047] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the present invention, the singular forms "a", "an", "the" and "the" used in the embodiments and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0049] In an embodiment of the present invention, a method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst comprises the following steps:

[0050] S1, dissolving a zinc salt and a cobalt salt in methanol, performing ultrasonic vibration, and then standing at room temperature to form a coordination compound to obtain a first solution;

[0051] S2. Dissolve 2-methylimidazole in methanol and stir at 20° C. to 40° C. to form a ligand dispersion system to obtain a second solution;

[0052] S3, mixing the second solution with the first solution at 20° C. to 40° C., and then standing to age to form a precipitate, and then centrifuging the obtained precipitate, washing, and drying to obtain a precursor;

[0053] S4. calcining the precursor under an inert atmosphere to obtain the high-performance transition metal-based zinc-air battery cathode catalyst.

[0054] In some implementations, in step S1, the zinc salt and the cobalt salt are zinc sulfate heptahydrate and cobalt sulfate heptahydrate, respectively; and / or

[0055] The molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:(1-4); and / or

[0056] The molar volume ratio of the zinc salt to methanol is 1 mol: (50-150) mL.

[0057] In some implementations, in step S1, the ultrasonic oscillation time is 3 min to 5 min; and / or

[0058] The standing time at room temperature is 1 h to 5 h.

[0059] In some implementations, in step S2, the mass ratio of 2-methylimidazole to methanol is (0.01-0.1):1; and / or

[0060] The stirring time is 1 h to 5 h.

[0061] In some implementations, in step S3, the mass ratio of the first solution to the second solution is 1:(1-1.5); and / or

[0062] The standing time is 8 hours to 24 hours.

[0063] In some implementations, in step S3, the washing is performed 3 to 6 times with methanol; and / or

[0064] The drying temperature is 78° C. to 82° C., and the drying time is 8 hours to 10 hours.

[0065] In some implementations, in step S4, the inert atmosphere is an argon atmosphere or a nitrogen atmosphere.

[0066] In some implementations, in step S4, the calcination temperature is 600° C. to 1200° C., and the calcination time is 1 hour to 5 hours.

[0067] In an embodiment of the present invention, a high-performance transition metal-based zinc-air battery cathode catalyst is prepared by the above-mentioned method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst.

[0068] In an embodiment of the present invention, a zinc-air battery includes the above-mentioned high-performance zinc-air battery cathode catalyst based on transition metals.

[0069] The following describes the details in conjunction with specific embodiments.

[0070] Example 1

[0071] A method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst comprises the following steps:

[0072] S1. Dissolve zinc sulfate heptahydrate and cobalt sulfate heptahydrate in methanol, perform ultrasonic vibration for 4 minutes, and then stand at room temperature for 2 hours to form a coordination compound to obtain a first solution. In this embodiment, the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:4; the molar volume ratio of zinc sulfate heptahydrate to methanol is 1 mol:100 mL.

[0073] S2. Dissolve 2-methylimidazole in methanol and stir at 40° C. for 3 h to form a ligand dispersion system to obtain a second solution. In this embodiment, the mass ratio of 2-methylimidazole to methanol is 0.05:1.

[0074] S3, mixing the second solution with the first solution at 40° C., and then standing for 16 hours to age to form a precipitate, and then centrifuging the obtained precipitate, washing it with methanol four times, and then drying it at 80° C. for 9 hours to obtain a precursor; in this embodiment, the mass ratio of the first solution to the second solution is 1:1.2;

[0075] S4. Calcine the precursor at 900 °C for 2 h in an argon atmosphere with a heating rate of 5 °C min -1 , that is, a high-performance zinc-air battery cathode catalyst based on transition metals was prepared, which was recorded as Zn1Co4@NC.

[0076] Example 2

[0077] A method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst is disclosed. This embodiment differs from Example 1 in that the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:1. The remaining preparation methods of this embodiment are the same as those of Example 1. The resulting high-performance transition metal-based zinc-air battery cathode catalyst is designated as Zn1Co1@NC.

[0078] Example 3

[0079] A method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst is provided. This embodiment differs from Example 1 in that the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:1.5, or 2:3. The remaining preparation methods of this embodiment are the same as those of Example 1. The resulting high-performance transition metal-based zinc-air battery cathode catalyst is designated Zn2Co3@NC.

[0080] Example 4

[0081] A method for preparing a high-performance zinc-air battery cathode catalyst based on a transition metal, the difference between this embodiment and embodiment 1 is that the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1.5:3.5. The rest of the preparation method of this embodiment is the same as that of embodiment 1. The prepared high-performance zinc-air battery cathode catalyst based on a transition metal is denoted as Zn 1.5 Co 3.5 @NC.

[0082] Example 5

[0083] A method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst comprises the following steps:

[0084] S1. Dissolve zinc sulfate heptahydrate and cobalt sulfate heptahydrate in methanol, perform ultrasonic vibration for 3 minutes, and then stand at room temperature for 1 hour to form a coordination compound to obtain a first solution. In this embodiment, the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:2; the molar volume ratio of zinc sulfate heptahydrate to methanol is 1 mol:150 mL.

[0085] S2. Dissolve 2-methylimidazole in methanol and stir at 20° C. for 1 hour to form a ligand dispersion system to obtain a second solution. In this embodiment, the mass ratio of 2-methylimidazole to methanol is 0.01:1.

[0086] S3, mixing the second solution with the first solution at 20° C., and then standing for 8 to 24 hours to age to form a precipitate, then centrifuging the obtained precipitate, washing it three times with methanol, and then drying it at 78° C. for 10 hours to obtain a precursor; in this embodiment, the mass ratio of the first solution to the second solution is 1:1;

[0087] S4. The precursor is calcined at 600° C. for 5 h under a nitrogen atmosphere to obtain a high-performance transition metal-based zinc-air battery cathode catalyst.

[0088] Example 6

[0089] A method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst comprises the following steps:

[0090] S1. Dissolve zinc sulfate heptahydrate and cobalt sulfate heptahydrate in methanol, perform ultrasonic vibration for 5 minutes, and then stand at room temperature for 5 hours to form a coordination compound to obtain a first solution. In this embodiment, the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:3; the molar volume ratio of zinc sulfate heptahydrate to methanol is 1 mol:50 mL.

[0091] S2. Dissolve 2-methylimidazole in methanol and stir at 30° C. for 5 h to form a ligand dispersion system to obtain a second solution. In this embodiment, the mass ratio of 2-methylimidazole to methanol is 0.1:1.

[0092] S3. The second solution and the first solution are mixed at 30° C., and then allowed to stand for 24 hours to age to form a precipitate. The resulting precipitate is then centrifuged and washed with methanol six times, and then dried at 82° C. for 8 to 10 hours to obtain a precursor. In this embodiment, the mass ratio of the first solution to the second solution is 1:1.5.

[0093] S4. The precursor is calcined at 1200° C. for 1 hour under an argon atmosphere to obtain a high-performance transition metal-based zinc-air battery cathode catalyst.

[0094] Example 7

[0095] A method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst comprises the following steps:

[0096] S1. Dissolve zinc sulfate heptahydrate and cobalt sulfate heptahydrate in methanol, perform ultrasonic vibration for 3.5 minutes, and then stand at room temperature for 3 hours to form a coordination compound to obtain a first solution. In this embodiment, the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:2.5; the molar volume ratio of zinc sulfate heptahydrate to methanol is 1 mol:80 mL.

[0097] S2. Dissolve 2-methylimidazole in methanol and stir at 25° C. for 2 h to form a ligand dispersion system to obtain a second solution. In this embodiment, the mass ratio of 2-methylimidazole to methanol is 0.03:1.

[0098] S3, mixing the second solution with the first solution at 25° C., and then standing for 12 hours to age to form a precipitate, and then centrifuging the obtained precipitate, washing it with methanol four times, and then drying it at 79° C. for 9.5 hours to obtain a precursor; in this embodiment, the mass ratio of the first solution to the second solution is 1:1.1;

[0099] S4. The precursor is calcined at 700° C. for 4 h under a nitrogen atmosphere to obtain a high-performance transition metal-based zinc-air battery cathode catalyst.

[0100] Example 8

[0101] A method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst comprises the following steps:

[0102] S1. Dissolve zinc sulfate heptahydrate and cobalt sulfate heptahydrate in methanol, perform ultrasonic vibration for 4.5 minutes, and then stand at room temperature for 4 hours to form a coordination compound to obtain a first solution. In this embodiment, the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:1.5; the molar volume ratio of zinc sulfate heptahydrate to methanol is 1 mol:120 mL.

[0103] S2. Dissolve 2-methylimidazole in methanol and stir at 35° C. for 4 h to form a ligand dispersion system to obtain a second solution. In this embodiment, the mass ratio of 2-methylimidazole to methanol is 0.08:1.

[0104] S3, mixing the second solution with the first solution at 35° C., and then standing for 18 hours to age to form a precipitate, then centrifuging the obtained precipitate, washing it with methanol five times, and then drying it at 81° C. for 8.5 hours to obtain a precursor; in this embodiment, the mass ratio of the first solution to the second solution is 1:1.4;

[0105] S4. The precursor is calcined at 1000° C. for 2 h under a nitrogen atmosphere to obtain a high-performance transition metal-based zinc-air battery cathode catalyst.

[0106] Example 9

[0107] A zinc-air battery comprises any one of embodiments 1 to 8 of the high-performance transition metal-based zinc-air battery cathode catalyst.

[0108] Comparative Example 1

[0109] A method for preparing a cathode catalyst is described. This comparative example differs from Example 1 in that cobalt sulfate heptahydrate is not added in step S1. The remaining preparation methods of this comparative example are the same as those of Example 1. The resulting cathode catalyst is designated Zn@NC.

[0110] Comparative Example 2

[0111] A method for preparing a cathode catalyst is described. This comparative example differs from Example 1 in that zinc sulfate heptahydrate is not added in step S1. The remaining preparation methods of this comparative example are the same as those of Example 1. The resulting cathode catalyst is designated Co@NC.

[0112] Structural morphology characterization by scanning electron microscopy

[0113] The high-performance transition metal-based zinc-air battery cathode catalyst (Zn1Co4@NC) prepared in Example 1 was characterized by scanning electron microscopy (SEM), and two SEM images with different magnifications were collected, as shown in FIG. Figure 1 and Figure 2 shown.

[0114] Depend on Figure 1 It can be seen that the Zn1Co4@NC prepared in Example 1 is a hollow sphere with openings and a rough and porous surface. Figure 2 As can be seen, the Zn1Co4@NC prepared in Example 1 is a hollow nanosphere with openings, and the surface of the sphere is rough with numerous nanoscale protrusions, gaps, and pores. Therefore, this high-performance transition metal-based zinc-air battery cathode catalyst has the advantage of a large specific surface area, which in turn gives the cathode catalyst excellent catalytic activity and stability.

[0115] X-ray diffraction analysis

[0116] The Zn1Co4@NC, Zn1Co1@NC, Zn2Co3@NC, Zn 1.5 Co 3.5 @NC, and Zn@NC and Co@NC prepared in Comparative Example 1 and Comparative Example 2, respectively, were subjected to X-ray diffraction analysis. The test results are as follows: Figure 3 shown.

[0117] Depend on Figure 3 It can be seen that for the Zn@NC catalyst without Co introduction, an obvious and broad characteristic peak appears at 2θ≈26.0°, which corresponds to the (002) crystal plane of graphite carbon. 1.5 Co 3.5 @NC and Co@NC catalysts, their XRD patterns show three obvious peaks at 44.2°, 51.5° and 75.9°, corresponding to the (111), (200) and (220) crystal planes of elemental Co (standard card number JCPDF#00-015-0806), respectively, indicating that cobalt has been successfully introduced into a high-performance transition metal-based zinc-air battery cathode catalyst of the present invention.

[0118] Oxygen reduction reaction (ORR) analysis

[0119] The Zn1Co4@NC, Zn1Co1@NC, Zn2Co3@NC, Zn 1.5 Co 3.5The linear sweep voltammetry (LSV) analysis of oxygen reduction reaction (ORR) was performed on Zn@NC, Zn@NC and Co@NC prepared in comparative examples 1 and 2, respectively, and commercial Pt / C catalysts. Figure 4 shown.

[0120] In addition, Zn1Co4@NC, Zn1Co1@NC, Zn2Co3@NC, Zn 1.5 Co 3.5 @NC, Zn@NC and Co@NC prepared in comparative examples 1 and 2, respectively, and commercial Pt / C catalysts were subjected to oxygen reduction reaction (ORR) half-wave potential (E 1 / 2 ) and limiting current density (J L ) histogram analysis, the analysis results are as follows Figure 5 shown.

[0121] Depend on Figure 4 and Figure 5 It can be seen that in the oxygen reduction reaction (ORR) activity test, the Zn1Co4@NC catalyst of Example 1 exhibited the best ORR activity (0.84 V, 5.72 mA cm -2 ), its half-wave potential and limiting current density are better than those of Zn x Co y The half-wave potential and limiting current density of the NC catalyst are even close to those of commercial Pt / C catalysts (0.85 V, 4.90 mA cm -2 ). It shows that in the present invention, when the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:4, the high-performance zinc-air battery cathode catalyst based on transition metals has the most excellent oxygen reduction reaction activity.

[0122] Oxygen evolution reaction (OER) analysis

[0123] The Zn1Co4@NC, Zn1Co1@NC, Zn2Co3@NC, Zn 1.5 Co 3.5 The linear sweep voltammetry (LSV) analysis of oxygen evolution reaction (OER) was performed on Zn@NC, Zn@NC and Co@NC prepared in comparative examples 1 and 2, respectively, and commercial RuO2 catalysts. The results are shown in Figure 2. Figure 6 shown.

[0124] In addition, Zn1Co4@NC, Zn1Co1@NC, Zn2Co3@NC, Zn 1.5 Co 3.5@NC, Zn@NC and Co@NC prepared in Comparative Example 1 and Comparative Example 2, respectively, and commercial RuO2 catalysts were tested at 10 mA·cm -2 The OER overpotential comparison analysis was carried out under Figure 7 shown.

[0125] Depend on Figure 6 and Figure 7 It can be seen that in the oxygen evolution reaction (OER) activity test, the Zn1Co4@NC catalyst of Example 1 exhibits the best OER activity (at 10 mA·cm -2 The overpotential under the condition of 337mV is better than that of Zn synthesized by other Zn-Co ratios. x Co y The @NC catalyst has an overpotential closest to that of the commercial RuO2 catalyst (280 mV). This indicates that the high-performance transition metal-based zinc-air battery cathode catalyst prepared in the present invention, when the molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:4, exhibits the most excellent oxygen evolution reaction activity.

[0126] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst, characterized in that: The following steps are involved: S1, dissolving a zinc salt and a cobalt salt in methanol, performing ultrasonic vibration, and then standing at room temperature to form a coordination compound to obtain a first solution; S2. Dissolve 2-methylimidazole in methanol and stir at 20° C. to 40° C. to form a ligand dispersion system to obtain a second solution; S3, mixing the second solution with the first solution at 20° C. to 40° C., and then standing to age to form a precipitate, and then centrifuging the obtained precipitate, washing, and drying to obtain a precursor; S4. calcining the precursor under an inert atmosphere to obtain the high-performance transition metal-based zinc-air battery cathode catalyst.

2. The method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst according to claim 1, wherein: In step S1, the zinc salt and the cobalt salt are zinc sulfate heptahydrate and cobalt sulfate heptahydrate respectively; and / or The molar ratio of zinc sulfate heptahydrate to cobalt sulfate heptahydrate is 1:(1-4); and / or The molar volume ratio of the zinc salt to methanol is 1 mol: (50-150) mL.

3. The method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst according to claim 1, wherein: In step S1, the ultrasonic oscillation time is 3 minutes to 5 minutes; and / or The standing time at room temperature is 1 h to 5 h.

4. The method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst according to claim 1, wherein: In step S2, the mass ratio of 2-methylimidazole to methanol is (0.01-0.1):1; and / or The stirring time is 1 h to 5 h.

5. The method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst according to claim 1, wherein: In step S3, the mass ratio of the first solution to the second solution is 1:(1-1.5); and / or The standing time is 8 hours to 24 hours.

6. The method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst according to claim 1, wherein: In step S3, the washing is performed by washing with methanol 3 to 6 times; and / or The drying temperature is 78° C. to 82° C., and the drying time is 8 hours to 10 hours.

7. The method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst according to claim 1, wherein: In step S4, the inert atmosphere is an argon atmosphere or a nitrogen atmosphere.

8. The method for preparing a high-performance transition metal-based zinc-air battery cathode catalyst according to claim 1, wherein: In step S4, the calcination temperature is 600° C. to 1200° C., and the calcination time is 1 hour to 5 hours.

9. A high-performance transition metal-based zinc-air battery cathode catalyst, characterized in that: It is prepared by the preparation method of a high-performance zinc-air battery cathode catalyst based on transition metal according to any one of claims 1 to 8.

10. A zinc-air battery, characterized in that: The invention comprises a high-performance zinc-air battery positive electrode catalyst based on transition metal as described in claim 9.

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