Multi-metal oxide catalyst for wide temperature range zinc-air battery and application thereof

Abstract

The application provides a multi-metal oxide catalyst for a wide-temperature-range zinc-air battery and application thereof. The multi-metal oxide catalyst comprises an ABCD multi-metal oxide, A is one of Al, Ga, Ge, In, Sn, Sb, Ti, Pb, Bi, Nb, Mo and Cd, B and C are respectively one of V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Zn, Zr and Y, and D is one of Pt, Ir, Ru, Pd, Au and Ag. The catalyst can improve the OER and ORR performance, has an ultra-long service life, and when the catalyst is applied to an air positive electrode of a zinc-air battery, the battery has not only high specific capacity and large power density, but also excellent cycle stability in a wide temperature range.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to multi-metal oxide catalysts for wide-temperature-range zinc-air batteries and their applications, and more specifically, to multi-metal oxide catalysts for wide-temperature-range zinc-air batteries, their preparation methods, and zinc-air batteries. Background Technology

[0002] Large-scale energy storage technology is a key core technology for building a new power system dominated by new energy sources and achieving the goals of "carbon peaking and carbon neutrality". Rechargeable zinc-air batteries (RZABs) have high energy density (1086 Wh / kg). -1 With advantages such as low material cost, green and pollution-free operation, high safety, and ease of storage and operation, RZABs have shown great application prospects in the field of large-scale renewable energy storage. However, the slow OER (oxygen evolution) and ORR (oxygen reduction) processes on the air electrode during charging and discharging severely limit the energy efficiency of RZABs and reduce the cycle life of the battery.

[0003] Currently, a series of bifunctional oxygen catalysts have been developed, including single-atom catalysts and heterogeneous coupling catalysis based on metal oxides / sulfides / phosphides / hydroxides, etc. However, bifunctional oxygen catalysts for use in alkaline aqueous RZABs over a wide temperature range are rarely reported. Operating at both low and high temperatures places high demands on the catalysts, especially at low temperatures where the slower electrochemical kinetics are unfavorable for the reactions of oxygen-containing species at the active sites. Therefore, further research is needed on catalysts for alkaline aqueous RZABs over a wide temperature range. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in the related art. Therefore, one object of this invention is to provide a multi-metal oxide catalyst for a wide-temperature-range zinc-air battery, which exhibits excellent electrocatalytic oxygen reduction (ORR) and oxygen evolution (OER) performance, while a zinc-air battery using this multi-metal oxide catalyst as the positive electrode demonstrates good performance over a wide temperature range.

[0005] In this invention, a multi-metal oxide catalyst for a wide-temperature-range zinc-air battery is provided. According to embodiments of the invention, the multi-metal oxide catalyst comprises an ABCD multi-metal oxide, wherein A is one of Al, Ga, Ge, In, Sn, Sb, Ti, Pb, Bi, Nb, Mo, and Cd; B and C are one of V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Zn, Zr, and Y, respectively; and D is one of Pt, Ir, Ru, Pd, Au, and Ag. Thus, by changing the content of different metals in the ABCD multi-metal oxide, the electronic structure of the catalyst can be regulated, optimizing the adsorption energy of oxygen-containing intermediate species (OOH*, O*, and OH*) at OER and ORR sites, thereby improving the OER and ORR performance of the multi-metal oxide catalyst. Simultaneously, the resulting catalyst exhibits an ultra-long lifetime. Furthermore, when this multi-metal oxide catalyst is applied to the air cathode of a zinc-air battery, the assembled zinc-air battery not only exhibits high specific capacity and high power density over a wide temperature range but also excellent cycle stability.

[0006] According to an embodiment of the present invention, in the ABCD multi-metal oxide, the atomic percentage of A is 0.001-99.9 at%, the atomic percentage of B is 0.001-99.9 at%, the atomic percentage of C is 0.01-99.9 at%, and the atomic percentage of D is 0.01-99.9 at%.

[0007] According to an embodiment of the present invention, in the ABCD multi-metal oxide, the atomic percentage of A is 1-10 at%, the sum of the atomic percentages of B and C is 10-25 at%, and the atomic percentage of D is 50-70 at%.

[0008] According to an embodiment of the present invention, the multi-metal oxide catalyst has a porous structure.

[0009] In another aspect, the present invention provides a method for preparing the aforementioned multi-metal oxide catalyst. According to an embodiment of the present invention, the method for preparing the multi-metal oxide catalyst includes: adding a carbon source and a decomposing agent to a metal precursor salt solution and stirring until homogeneous to obtain a mixed solution; freeze-drying the mixed solution to obtain a frozen intermediate product; and calcining the frozen intermediate product to obtain the multi-metal oxide catalyst, wherein the decomposing agent decomposes to generate gas during the calcination process. Thus, the above method can prepare a multi-metal oxide catalyst, which is simple, low-cost, environmentally friendly, and easy to scale up. By changing the content of different metals in the ABCD multi-metal oxide, the electronic structure of the multi-metal oxide catalyst can be controlled, optimizing the adsorption energy of oxygen-containing intermediate species (OOH*, O*, and OH*) at OER and ORR sites, thereby improving the OER and ORR performance of the multi-metal oxide catalyst, while the obtained catalyst has an ultra-long lifetime. Moreover, when this multi-metal oxide catalyst is applied to the air cathode of a zinc-air battery, the assembled zinc-air battery not only exhibits high specific capacity and high power density over a wide temperature range but also excellent cycle stability.

[0010] According to an embodiment of the present invention, the concentration of the metal precursor salt in the metal precursor salt solution is 0.001-100 mg / mL.

[0011] According to an embodiment of the present invention, the mass ratio of the carbon source to the decomposition agent is 1:100-1:1.

[0012] According to an embodiment of the present invention, the carbon source includes at least one of galactose, sucrose, fructose, glucose and maltose, and the decomposing agent includes at least one of thiourea, ammonium chloride, urea and ammonium sulfate.

[0013] According to an embodiment of the present invention, the freeze-drying treatment is performed at a temperature of -50 to 0°C for a time of 0.1 to 200 h; and / or the calcination treatment is performed at a temperature of 200 to 1500°C for a time of 0.1 to 1800 h.

[0014] In another aspect, the present invention provides a zinc-air battery. According to an embodiment of the invention, the zinc-air battery comprises the aforementioned multi-metal oxide catalyst. Therefore, the zinc-air battery exhibits high specific capacity, high power density, and excellent cycle stability. Attached Figure Description

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0016] Figure 1 This is a scanning electron microscope image of the multi-metal oxide catalyst in Example 9 of the present invention;

[0017] Figure 2 This is a stability test curve of the multi-metal oxide catalyst in Example 9 of the present invention;

[0018] Figure 3 In this diagram, 'a' is a schematic diagram of the zinc-air battery module in Embodiment 9 of the present invention;

[0019] Figure 3 In the figure, b is the open-circuit voltage curve of the zinc-air battery in Embodiment 9 of the present invention;

[0020] Figure 3 In the figure, c is the power density curve of the zinc-air battery in Embodiment 9 of the present invention;

[0021] Figure 3 In this context, d represents the specific capacity curve of the zinc-air battery in Embodiment 9 of the present invention.

[0022] Figure 4 This is a test graph showing the constant current charge-discharge stability of the zinc-air battery in Example 9 of the present invention under a wide temperature range (room temperature, low temperature and high temperature). Detailed Implementation

[0023] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0024] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0025] In an aspect of the present invention, the present invention provides a multi-metal oxide catalyst for a wide-temperature-range zinc-air battery. According to an embodiment of the present invention, the multi-metal oxide catalyst comprises an ABCD multi-metal oxide, wherein A is one of Al, Ga, Ge, In, Sn, Sb, Ti, Pb, Bi, Nb, Mo and Cd, B and C are each one of V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Zn, Zr and Y, and D is one of Pt, Ir, Ru, Pd, Au and Ag, where 0≤x<1, 0≤y<1, 0<z<1, and 0<x + y + z<1, and x and y are not both 0. Thus, in this multi-metal oxide catalyst, by changing the contents of different metals in the ABCD multi-metal oxide, the electronic structure of the catalyst can be regulated to optimize the adsorption energies of oxygen-containing intermediate species (OOH*, O* and OH*) on the OER and ORR sites, improving the OER and ORR performance of the multi-metal oxide catalyst, and at the same time, the obtained catalyst has an ultra-long lifespan; moreover, when this multi-metal oxide catalyst is applied to the air cathode of a zinc-air battery, the assembled zinc-air battery not only has a high specific capacity and a large power density in a wide temperature range, but also has excellent cycle stability performance.

[0026] In a zinc-air battery, for the oxygen reduction (ORR) reaction, in an alkaline environment, oxygen undergoes a 4-electron reaction to generate OH - , and the ORR active sites of the multi-metal oxide catalyst of the present invention are conducive to O2 gaining electrons and being reduced to OH-, reducing the reaction energy barrier. The oxygen evolution (OER) reaction is theoretically the reverse reaction of ORR. In an alkaline environment, OH in the solution - , loses electrons and becomes oxygen, and the OER active sites in the multi-metal oxide catalyst of the present invention are conducive to the progress of this reaction. That is to say, the multi-metal oxide catalyst of the present invention has excellent OER and ORR performance, which is beneficial to improving the reaction activity of the zinc-air battery at low and high temperatures in a wide temperature range.

[0027] In some embodiments, the temperature range of the wide temperature range can be -20 - 60 degrees Celsius.

[0028] It should be noted that ABCD is not the chemical formula of the multi-metal oxide, but only represents the metal elements contained in the multi-metal oxide, that is, it means that the multi-metal oxide contains four metal elements A, B, C and D, and all four metal elements exist in the form of metal oxides. In some embodiments of the present invention, in the ABCD multi-metal oxide, the metal element B and the metal element C can be the same metal element or two different metal elements, so the ABCD multi-metal oxide of the present invention is a ternary metal oxide or a quaternary metal oxide.

[0029] According to some embodiments of the present invention, in the ABCD multi-metal oxide, the sum of the atomic percentages of A, B, C, D, and oxygen atoms is 100 at%, wherein the atomic percentage of A is 0.001-99.9 at% (e.g., 0.001 at%, 0.01 at%, 0.1 at%, 1 at%, 10 at%, 20 at%, 30 at%, 40 at%, 50 at%, 60 at%, 70 at%, 80 at%, 90 at%, 95 at%, 99.9 at%, etc.), the atomic percentage of B is 0.001-99.9 at% (e.g., 0.001 at%, 0.01 at%, 0.1 at%, 1 at%, 10 at%, 20 at%, 30 at%, 40 at%, 50 at%, 60 at%, 70 at%, 80 at%, 90 at%, 95 at%, 99.9 at%, etc.), and the atomic percentage of C is 0.01-99.9 at%. at% (e.g., 0.01 at%, 0.1 at%, 1 at%, 10 at%, 20 at%, 30 at%, 40 at%, 50 at%, 60 at%, 70 at%, 80 at%, 90 at%, 95 at%, 99.9 at%), etc.), and the atomic percentage of D is 0.01-99.9 at% (e.g., 0.01 at%, 0.1 at%, 1 at%, 10 at%, 20 at%, 30 at%, 40 at%, 50 at%, 60 at%, 70 at%, 80 at%, 90 at%, 95 at%, 99.9 at%).

[0030] In some specific embodiments, in the ABCD multi-metal oxide, the atomic percentage of A is 1-10 at%, the sum of the atomic percentages of B and C is 10-25 at%, and the atomic percentage of D is 50-70 at%.

[0031] According to embodiments of the present invention, the multi-metal oxide catalyst has a porous structure. Thus, the porous structure has a relatively large specific surface area, which can help to further improve catalytic efficiency.

[0032] In some embodiments, the multi-metal oxide catalyst is foam-like and is composed of nanoscale metal oxide particles.

[0033] In another aspect, the present invention provides a method for preparing the aforementioned multi-component metal oxide catalyst. According to an embodiment of the present invention, the method for preparing the multi-component metal oxide catalyst includes:

[0034] S100: Add the carbon source and decomposition agent to the metal precursor salt solution and stir until homogeneous to obtain a mixed solution.

[0035] According to some embodiments of the present invention, the carbon source includes at least one of galactose, sucrose, fructose, glucose, and maltose. Therefore, the carbon source, when carbonized in the subsequent calcination process, facilitates the uniform dispersion of metal ions, and is widely available, easy to purchase, and inexpensive.

[0036] According to some embodiments of the present invention, the decomposing agent includes at least one of thiourea, ammonium chloride, urea, ammonium bicarbonate, and ammonium sulfate. Thus, the aforementioned decomposing agent decomposes during a heating process (such as a subsequent calcination process) to generate gas, which facilitates the formation of a loose and porous multi-component metal oxide catalyst structure. In some embodiments, a porous foam-like catalyst can be formed, which is composed of nanoscale metal oxide particles stacked together.

[0037] According to some embodiments of the present invention, there are no special requirements for the specific type of metal precursor salt in the above-mentioned metal precursor salt solution. Those skilled in the art can flexibly select its soluble salt according to the specific metal type selected, such as metal halide salt, metal ammonium salt, etc.

[0038] According to some embodiments of the present invention, the mass ratio of carbon source to decomposer is 1:100-1:1, such as 1:100, 1:90, 1:80, 1:70, 1:60, 1:50, 1:40, 1:30, 1:20, 1:10, 1:5, 1:1, etc. The above mass ratios help to form a good and structurally stable multi-metal oxide catalyst. If the proportion of carbon source is large, that is, the proportion of decomposer is relatively small, the amount of gas generated by decomposition is insufficient, which is relatively unfavorable for the formation of a porous structure in the multi-metal oxide catalyst. If the proportion of carbon source is relatively small, that is, the proportion of decomposer is relatively large, then the amount of gas generated is excessive, resulting in a relatively large porous structure size in the multi-metal oxide catalyst, which in turn leads to a relatively small specific surface area. This is not conducive to improving the catalytic effect and may also lead to insufficient structural stability of the multi-metal oxide catalyst.

[0039] According to some embodiments of the present invention, the concentration of the metal precursor salt in the metal precursor salt solution is 0.001-100 mg / mL, for example, 0.001 mg / mL, 0.01 mg / mL, 0.1 mg / mL, 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, 10 mg / mL, 20 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, etc. Wherein, the above concentrations refer to the total concentration of various metal precursor salts.

[0040] In some embodiments of the present invention, the specific method of stirring described above may include, but is not limited to, magnetic stirring, mechanical stirring, ultrasonic stirring, etc.

[0041] S200: The mixed solution is freeze-dried to obtain a freeze intermediate product, namely, a freeze-dried mixed metal precursor salt.

[0042] According to some embodiments of the present invention, freeze-drying can be performed in a freeze dryer. In some embodiments, the freeze-drying temperature is -50 to 0°C, such as -50°C, -45°C, -40°C, -35°C, -30°C, -25°C, -20°C, -15°C, -10°C, -5°C, 0°C, etc., and the time is 0.1 to 200 h, such as 0.1 h, 1 h, 10 h, 20 h, 50 h, 75 h, 100 h, 120 h, 150 h, 170 h, 200 h, etc. Under the above conditions, the mixed solution can be frozen quickly and effectively.

[0043] In some embodiments, the frozen intermediate product may be a brown substance.

[0044] S300: The frozen intermediate product is calcined to obtain a multi-component metal oxide catalyst. In this process, the decomposing agent decomposes to produce gas, the carbon source carbonizes, and the metal precursor salt begins to decompose to generate metal oxides, forming a porous multi-component metal oxide catalyst under the action of the gas.

[0045] According to some embodiments of the present invention, the calcination temperature is 200-1500℃, such as 200℃, 500℃, 700℃, 900℃, 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, etc., and the time is 0.1-1800 h, such as 0.1h, 1h, 10h, 20h, 50h, 75h, 100h, 120h, 150h, 170h, 200h, 500h, 800h, 1000h, 1200h, 1500h, 1800h, etc.

[0046] According to some embodiments of the present invention, the above-described calcination process can be carried out in an oxygen-containing atmosphere, such as an air or oxygen atmosphere, in which the carbon source and metal salt decompose to generate gas and simultaneously generate metal oxides.

[0047] According to embodiments of the invention, a multi-metal oxide catalyst can be prepared by the above method. The preparation method is simple, low-cost, environmentally friendly, and easy to scale up. By changing the content of different metals in the ABCD multi-metal oxide, the electronic structure of the multi-metal oxide catalyst can be regulated, thereby optimizing the adsorption energy of oxygen-containing intermediate species (OOH*, O*, and OH*) at the OER and ORR sites, improving the OER and ORR performance of the multi-metal oxide catalyst, and the resulting catalyst has an ultra-long lifetime. Moreover, when this multi-metal oxide catalyst is applied to the air cathode of a zinc-air battery, the assembled zinc-air battery not only has high specific capacity and high power density over a wide temperature range, but also excellent cycle stability.

[0048] In another aspect, the present invention provides a zinc-air battery. According to an embodiment of the invention, the zinc-air battery comprises the aforementioned multi-metal oxide catalyst. Therefore, the zinc-air battery exhibits high specific capacity, high power density, and excellent cycle stability.

[0049] In an embodiment of the present invention, the zinc-air electrode includes a zinc electrode, a separator, an air electrode, and an electrolyte. The air electrode includes a current collector, a multi-metal oxide catalyst, and a hydrophobic gas collection layer stacked sequentially. When the battery discharges, the air electrode serves as the positive electrode of the battery.

[0050] Example

[0051] Example 1

[0052] Methods for preparing multi-metal oxide catalysts include:

[0053] (1) Weigh out a certain amount of (NH4)6Mo7O 24• 4H2O, SnCl2, IrCl3 and MnCl3 were dissolved in deionized water to make the total concentration of the metal precursor salt 10 mg / mL;

[0054] (2) Then add ammonium bicarbonate and sucrose (mass ratio 1:6, unit mg), and after continuous stirring, a clear mixed solution is obtained.

[0055] (3) Then the beaker containing the mixed solution was placed in a freeze dryer and dried at -50 °C for 48 h to obtain a brown substance loaded with a metal salt.

[0056] (4) Finally, the obtained brown substance was placed in a muffle furnace and calcined at 600 °C for 18 h in an air atmosphere to obtain a SnMoMnIr quaternary metal oxide catalyst (where the atomic percentages of Sn, Mo, Mn and Ir are 1 at %, 2 at %, 12 at %, and 60 at %), which is a multi-metal oxide catalyst.

[0057] Example 2

[0058] Methods for preparing multi-metal oxide catalysts include:

[0059] (1) Weigh a certain amount of BiCl3, IrCl3 and CoCl2•6H2O and dissolve them in deionized water to make the total concentration of metal precursor salt 8 mg / mL;

[0060] (2) Then add urea and galactose (mass ratio of 1:10, unit mg), and after continuous stirring, a clear mixed solution is obtained.

[0061] (3) Then the beaker containing the mixed solution was placed in a freeze dryer and dried at -40 °C for 28 h to obtain a brown substance loaded with a metal salt.

[0062] (4) Finally, the obtained brown substance was placed in a tube furnace and calcined at 300 °C for 12 h in an oxygen atmosphere to obtain a BiCoIr ternary metal oxide catalyst (in which the atomic percentages of Bi, Co and Ir are 2 at %, 15 at % and 55 at % respectively), thus obtaining a multi-metal oxide catalyst.

[0063] Example 3

[0064] Methods for preparing multi-metal oxide catalysts include:

[0065] (1) Weigh a certain amount of SbCl5, IrCl3 and MnCl2 and dissolve them in deionized water to make the total concentration of metal precursor salt 10 mg / mL;

[0066] (2) Then add thiourea and glucose (mass ratio of 1:30, unit mg), and stir continuously to obtain a clear mixed solution.

[0067] (3) Then the beaker containing the mixed solution was placed in a freeze dryer and dried at -50 °C for 24 hours to obtain a brown substance loaded with a metal salt.

[0068] (4) Finally, the obtained brown substance was placed in a muffle furnace and calcined at 550 °C for 14 h in an air atmosphere to obtain a SbMnIr ternary metal oxide catalyst (where the atomic percentages of Sn, Mn and Ir are 5 at %, 23 at % and 54 at % respectively), which is a multi-metal oxide catalyst.

[0069] Example 4

[0070] Methods for preparing multi-metal oxide catalysts include:

[0071] (1) Weigh a certain amount of AlCl3, IrCl3 and CoCl2•6H2O and dissolve them in deionized water to make the total concentration of metal precursor salt 10 mg / mL;

[0072] (2) Then ammonium chloride and sucrose (mass ratio 1:8, unit mg) were added, and a clear mixed solution was obtained by continuous stirring.

[0073] (3) Then the beaker containing the mixed solution was placed in a freeze dryer and dried at -45 °C for 48 h to obtain a brown substance loaded with a metal salt.

[0074] (4) Finally, the obtained brown substance was placed in a tube furnace and calcined at 600 °C for 18 h in an oxygen atmosphere to obtain an AlCoIr ternary metal oxide catalyst (in which the atomic percentages of Al, Co and Ir are 3 at %, 12 at % and 58 at % respectively), thus obtaining a multi-metal oxide catalyst.

[0075] Example 5

[0076] Methods for preparing multi-metal oxide catalysts include:

[0077] (1) Weigh out a certain amount of CoCl2•6H2O, SbCl5, PdCl2 and (NH4)6Mo7O 24 ·4H2O was dissolved in deionized water to make the total concentration of the metal precursor salt 10 mg / mL;

[0078] (2) Then add urea and fructose (mass ratio of 1:10, unit mg), and after continuous stirring, a clear mixed solution is obtained.

[0079] (3) Then the beaker containing the mixed solution was placed in a freeze dryer and dried at -50 °C for 24 hours to obtain a brown substance loaded with a metal salt.

[0080] (4) Finally, the obtained brown substance was placed in a muffle furnace and calcined at 550 °C for 12 h in an air atmosphere to obtain a SbCoMoPd quaternary metal oxide catalyst (where the atomic percentages of Sb, Co, Mo and Pd are 1 at %, 10 at %, 3 at % and 62 at % respectively), which is a multi-metal oxide catalyst.

[0081] Example 6

[0082] Methods for preparing multi-metal oxide catalysts include:

[0083] (1) Weigh a certain amount of CoCl2•6H2O, GaCl3, PdCl2 and FeCl3 and dissolve them in deionized water to make the total concentration of metal precursor salts 5 mg / mL;

[0084] (2) Then add urea and sucrose (mass ratio of 1:25, unit mg), and after continuous stirring, a clear mixed solution is obtained.

[0085] (3) Then the beaker containing the mixed solution was placed in a freeze dryer and dried at -45°C for 48 hours to obtain a brown substance loaded with a metal salt.

[0086] (4) Finally, the obtained brown substance was placed in a muffle furnace and calcined at 600 °C for 10 h in an air atmosphere to obtain a GaCoFePd quaternary metal oxide catalyst (where the atomic percentages of Ga, Co, Fe and Pd are 2 at %, 15 at %, 1 at % and 52 at % respectively), thus obtaining a multi-metal oxide catalyst.

[0087] Example 7

[0088] (1) Weigh a certain amount of FeCl3, GaCl3, K2PtCl6 and CoCl2•6H2O and dissolve them in ion water to make the total concentration of metal precursor salts 8 mg / mL.

[0089] (2) Then add ammonium bicarbonate and fructose (mass ratio of 1:35, unit mg), and obtain a clear mixed solution by continuous stirring.

[0090] (3) Then, the beaker containing the mixed solution was placed in a freeze dryer and dried at -30 °C for 50 h to obtain a brown substance loaded with a metal salt.

[0091] (4) Finally, the obtained brown substance was placed in a muffle furnace and calcined at 400 °C for 24 h in an air atmosphere to obtain a GaCoFePt quaternary metal oxide catalyst (in which the atomic percentages of Ga, Co, and Fe mixed with Pt were 1.5 at%, 12 at%, 1 at% and 56 at% respectively), thus obtaining a multi-metal oxide catalyst.

[0092] Example 8

[0093] (1) Weigh a certain amount of SnCl2, CoCl2•6H2O, PdCl2 and Cu(NO3)2•6H2O and dissolve them in ion water to make the total concentration of metal precursor salt 8 mg / mL.

[0094] (2) Then ammonium sulfate and glucose (mass ratio 1:5, unit mg) were added, and a clear mixed solution was obtained by continuous stirring.

[0095] (3) Then the beaker containing the mixed solution was placed in a freeze dryer and dried at -50 °C for 24 h to obtain a brown substance loaded with metal salt.

[0096] (4) Finally, the obtained brown substance was placed in a muffle furnace and calcined at 450 °C for 28 hours in an air atmosphere to obtain a SnCoCuPd quaternary metal oxide catalyst (where the atomic percentages of Sn, Co, Cu and Pd are 2 at %, 15 at %, 3 at % and 53 at % respectively), thus obtaining a multi-metal oxide catalyst.

[0097] Example 9

[0098] (1) Weigh a certain amount of GaCl3, MnSO4 and RuCl3 and dissolve them in ionized water to make the total concentration of metal precursor salt 8 mg / mL.

[0099] (2) Then ammonium sulfate and glucose (mass ratio 1:5, unit mg) were added, and a clear mixed solution was obtained by continuous stirring.

[0100] (3) Then the beaker containing the mixed solution was placed in a freeze dryer and dried at -50 °C for 24 h to obtain a brown substance loaded with metal salt.

[0101] (4) Finally, the obtained brown substance was placed in a muffle furnace and calcined at 450 °C for 28 h in an air atmosphere to obtain a GaMnRu ternary metal oxide catalyst (in which the percentage contents of Ga, Mn and Ru atoms were 2 at %, 12 at %, and 57 at %), which is a multi-metal oxide catalyst.

[0102] Morphological characterization of multi-metal oxide catalysts:

[0103] The morphological characteristics of the multi-metal oxide catalyst obtained in Example 9 were observed by scanning electron microscopy, such as... Figure 1 As shown, from the SEM image ( Figure 1 In diagram a), the multi-metal oxide catalyst appears as a porous foam sheet, as seen in TEM (exhibition of TEM images). Figure 1 As can be seen in b), the foam-like multi-metal oxide catalyst is composed of tiny nanoparticles of a few nanometers in size.

[0104] Characterization of ORR and OER performance of multi-metal oxide catalysts:

[0105] The multi-metal oxide catalyst obtained in Example 9, ethanol, and Nafion solution were mixed in a certain proportion to form a slurry (the multi-metal oxide catalyst content was 5 mg / ml). The slurry was then coated onto a rotating ring-disc electrode and subjected to linear sweep voltammetry in a three-electrode system (where the rotating ring-disc electrode was the working electrode, the Ag / AgCl electrode was the reference electrode, and the Pt wire was the counter electrode) to obtain the LSV curve, as shown below. Figure 2 As shown. Then, using Pt / C and IrO2 as a combined catalyst, linear sweep voltammetry was performed in the three-electrode system according to the above method to obtain the LSV curve, as shown. Figure 2 As shown in 'a'.

[0106] The LSV curves show that the ORR and OER performance of this multi-metal oxide catalyst are superior to those of commercial Pt / C and IrO2 catalysts, respectively, and the oxygen potential difference is 0.605 V, which is far superior to the combined catalyst of commercial Pt / C and IrO2, demonstrating excellent bifunctionality.

[0107] Stability test:

[0108] The stability of the multi-metal oxide catalyst obtained in Example 9 was tested by accelerated cycling (after a certain number of accelerated cycling cycles, LSV testing was performed), and the test results can be found in [reference needed]. Figure 2 b and Figure 2 c. This catalyst also exhibits good ORR stability, remaining stable after 300,000 CV cycles ( Figure 2 (b) shows a small change in half-wave potential. The catalyst also exhibits good OER stability; after 30,000 CV cycles, the overpotential remained essentially unchanged. Figure 2 (c in the text)

[0109] Performance characterization of zinc-air batteries using multi-metal oxide catalysts as air electrode materials at room temperature and low temperature:

[0110] The multi-metal oxide catalyst obtained in Example 9, ethanol, and Nafion solution were mixed in a certain proportion to form a slurry. The slurry was then coated onto a composite electrode substrate (multi-metal oxide catalyst content 1 mg cm⁻¹). -2 ), and assembled into zinc-air battery modules (such as Figure 3 (a) Test the open-circuit voltage of the zinc-air battery (e.g.) Figure 3 b) Power density (e.g.) Figure 3 c) and specific capacity (e.g. Figure 3 (d) For the zinc-air battery containing a polymetallic oxide catalyst, its open-circuit voltage at room temperature is 1.59 V and its specific capacity is 968.5 mAh g. Zn -1 Power density is 200 mW / cm² -2 Both are superior to batteries using commercially available Pt / C+IrO2 combined catalysts as air electrode materials (open-circuit voltage 1.54 V, specific capacity 741.1 mAh g). Zn -1 The power density is 116.3 mW / cm². -2 The performance at low temperatures (-20℃) is also superior to that of the Pt / C+IrO2 combined catalyst. At low temperatures, the power density of the zinc-air battery containing the multi-metal oxide catalyst can reach 87.1 mW cm⁻¹. -2 And its specific capacity is 825.6 mAh g. Zn -1 It outperforms batteries using commercially available Pt / C+IrO2 combined catalysts as air electrode materials (specific capacity of 718.1 mAh g⁻¹). Zn -1 Power density below 20mW cm -2 Therefore, it can be seen that the multi-metal oxide catalyst of the present invention has better performance as an air electrode at both low temperature and room temperature.

[0111] Constant current charge-discharge stability of zinc-air batteries using multi-metal oxide catalysts as air electrode materials over a wide temperature range (room temperature, low temperature, and high temperature):

[0112] from Figure 4 As can be seen in section a, when the polymetallic oxide catalyst obtained in Example 9 is used as the air electrode material, it shows almost no degradation after 800 hours of constant current charge-discharge testing at room temperature, while the commercial Pt / C+IrO2 combined catalyst shows significant degradation after more than 100 hours of operation. Similarly, from... Figure 4As can be seen from b in 4 and c in 4, the multi-metal oxidation catalyst has excellent cycle stability at both low and high temperatures, which is far superior to the commercial Pt / C+IrO2 combined catalyst. In particular, it can operate stably for more than 2000 hours at low temperature with almost no degradation.

[0113] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0114] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a multi-metal oxide catalyst for a wide temperature range zinc-air battery, characterized by, include: The carbon source and decomposition agent are added to the metal precursor salt solution and stirred until homogeneous to obtain a mixed solution. The mixed solution was freeze-dried to obtain a frozen intermediate product; The frozen intermediate product is calcined in air to obtain the multi-element metal oxide catalyst, wherein the decomposing agent decomposes to generate gas during the calcination process. The multi-metal oxide catalyst comprises ABD multi-metal oxide, wherein A is Ga, B is Mn, and D is Ru. In the ABD multi-metal oxide, the atomic percentage of A is 2 at%, the atomic percentage of B is 12 at%, and the atomic percentage of D is 57 at%. The concentration of the metal precursor salt in the metal precursor salt solution is 0.001-100 mg / mL; The mass ratio of the carbon source to the decomposing agent is 1:100-1:1; The carbon source includes at least one of galactose, sucrose, fructose, glucose, and maltose, and the decomposing agent includes at least one of thiourea, ammonium chloride, urea, and ammonium sulfate; The freeze-drying process was carried out at a temperature of -50°C for 24 hours; the calcination process was carried out at a temperature of 450°C for 28 hours.

2. A zinc-air battery characterized by, This includes the multi-metal oxide catalyst prepared by the method of claim 1.

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