Five-element non-noble metal high-entropy alloy catalyst, preparation method thereof and application of five-element non-noble metal high-entropy alloy catalyst in flexible zinc-air battery

Abstract

The invention provides a pentabasic non-noble metal high-entropy alloy catalyst, a preparation method thereof and application of the pentabasic non-noble metal high-entropy alloy catalyst in a flexible zinc-air battery. The quinary non-noble metal high-entropy alloy catalyst is obtained by synthesizing metal salt containing Fe, Co, Ni, Cu and Mo, a surfactant and a reducing agent in one step under the low-temperature condition of 150-250 DEG C; the crystal structure is a face-centered cubic single-phase solid solution structure, and the average particle size is 80-90 nm. According to the iron-cobalt-nickel-copper-molybdenum high-entropy alloy catalyst, the electronic structure and active site distribution are optimized through the synergistic effect of multiple elements, the OER catalytic activity and stability are remarkably improved, the catalyst can adapt to the reaction environment with the high pH value and the large current density, and the catalyst has the advantages of being low in overpotential, high in stability, low in cost and the like. When being used as an air cathode electrocatalyst of a flexible zinc-air battery, the air cathode electrocatalyst also has good flexibility and excellent charge-discharge cycle stability while being comparable with the performance of a commercial noble metal catalyst, and has a wide application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic materials, and in particular relates to a five-element non-noble metal high-entropy alloy catalyst, a preparation method thereof, and an application thereof in a flexible zinc-air battery. Background Art

[0002] The oxygen evolution reaction (OER) is a core process in energy technologies such as water splitting and metal-air batteries. However, its slow four-electron transfer kinetics necessitate the development of efficient catalysts. Traditional noble metal catalysts (such as IrO2 and RuO2), while highly active, are expensive and resource-scarce. Non-noble metal catalysts (such as transition metal oxides and layered double hydroxides) generally face the dilemma of achieving both activity and stability.

[0003] In recent years, high-entropy alloys (HEAs) have become a cutting-edge research direction in catalytic materials due to their multi-principal element synergy, high configurational entropy stability, and tunable electronic structure. When reduced to nanometer size, HEAs nanoparticles possess very high surface area and numerous active sites, offering great potential for reducing the activation energy of OER reactions.

[0004] However, the synthesis process of high entropy alloys usually requires high temperature and high pressure conditions, which greatly increases their preparation cost. In addition, the process is prone to component segregation or phase separation due to differences in physical and chemical properties between elements, thereby affecting catalytic activity. A Chinese patent (CN115845858B) discloses a high entropy oxide and high entropy alloy catalyst material for lignin decomposition, but its preparation process is complicated and requires high-temperature calcination at 600°C, and a reducing atmosphere is also required for the preparation of the alloy. Another patent (CN118086948A) prepared a porous high entropy alloy catalyst with a B2-BCC structure and applied it to the field of PEM water electrolysis for hydrogen production, but the synthesis process involves high temperature and high current (melting current ≥250A, melting temperature ≥3000°C, annealing temperature of 1200-1400°C) and the preparation method is complicated. Moreover, although the synthesized high entropy alloy has a certain specific surface area, the particle diameter is relatively large at the micron level.

[0005] Therefore, developing a non-precious metal high-entropy alloy catalyst with high activity, high stability, simple process and efficient synthesis is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0006] The object of the present invention is to provide a five-element non-precious metal high-entropy alloy catalyst, its preparation method and application in flexible zinc-air batteries. Specifically, the FCC structure of the iron-cobalt-nickel-copper-molybdenum (FeCoNiCuMo) high-entropy alloy catalyst provided by the present invention has high symmetry and close-packed properties, which is conducive to the diffusion of atoms and the transmission of electrons. The single-phase solid solution structure can make multiple elements evenly distributed, avoid problems such as phase separation, and ensure the uniformity and stability of material properties. At the same time, the multi-element alloying effect can adjust the electronic structure of the catalyst and improve the catalytic activity, and multiple transition metal elements also have a lower material synthesis cost. In addition, the nanometer-scale size with an average particle size of 80-90nm has a large specific surface area, can provide more active sites, increase the contact area between the reactant and the catalyst, and thus improve the efficiency of the catalytic reaction. Moreover, the nano-sized grains can also shorten the electron transmission distance and accelerate the reaction kinetics process.

[0007] In terms of preparation method, the present invention provides a one-step synthesis method under relatively low temperature conditions, which has simple process, easy operation, low energy consumption requirements for equipment, and is particularly suitable for large-scale industrial production.

[0008] In terms of application methods, the iron-cobalt-nickel-copper-molybdenum high-entropy alloy catalyst provided by the present invention optimizes the electronic structure and active site distribution through the synergistic effect of multiple elements, significantly improving the OER catalytic activity and stability. It is adaptable to high pH and high current density reaction environments and has many advantages such as low overpotential, high stability, and low cost. As the air cathode electrocatalyst of flexible zinc-air batteries, it has good flexibility and excellent charge-discharge cycle stability while comparable to the performance of commercial precious metal catalysts, and has broad application prospects.

[0009] To achieve the above objectives, the present invention provides a method for preparing a five-element non-precious metal high-entropy alloy catalyst. The five-element non-precious metal high-entropy alloy catalyst is synthesized in one step by combining metal salts containing Fe, Co, Ni, Cu, and Mo with a surfactant and a reducing agent under low-temperature conditions of 150-250°C; its crystal structure is a face-centered cubic (FCC) single-phase solid solution structure, and the average particle size is 80-90nm.

[0010] In a preferred embodiment, the method comprises the following steps:

[0011] Step 1: Dissolve Fe(C5H7O2)3, Co(C5H7O2)2, Ni(C5H7O2)3, Cu(C5H7O2)3 and Mo(CO)6 in oleylamine (OAm), add surfactant and reducing agent, and mix by ultrasonication to obtain a precursor solution;

[0012] Step 2: Heat the precursor solution from step 1 to 150-250°C under inert gas protection and allow to react for a period of time to generate solid particles;

[0013] Step 3: Wash and dry the reaction product of step 2 to obtain a high entropy alloy catalyst.

[0014] In a preferred embodiment, in step one, the molar ratio of Fe(C5H7O2)3, Co(C5H7O2)2, Ni(C5H7O2)3, Cu(C5H7O2)3 and Mo(CO)6 is 1:(0.8-1.2):(0.8-1.2):(0.8-1.2):(0.8-1.2); preferably, the molar ratio of Fe(C5H7O2)3, Co(C5H7O2)2, Ni(C5H7O2)3, Cu(C5H7O2)3 and Mo(CO)6 is 1:1:1:1:1.

[0015] In a preferred embodiment, in step one, the volume ratio of the total amount of Fe(C5H7O2)3, Co(C5H7O2)2, Ni(C5H7O2)3, Cu(C5H7O2)3 and Mo(CO)6 to oleylamine is 2mmol:(6-9)ml; preferably, the volume ratio of the total amount of Fe(C5H7O2)3, Co(C5H7O2)2, Ni(C5H7O2)3, Cu(C5H7O2)3 and Mo(CO)6 to oleylamine is 4mmol:15ml.

[0016] In a preferred embodiment, in step 1, the surfactant includes octadecyltrimethylammonium bromide (STAB).

[0017] In a preferred embodiment, in step 1, the mass volume ratio of the surfactant to oleylamine is 0.1 g:(10-20) ml; preferably, the mass volume ratio of the surfactant to oleylamine is 0.1 g:15 ml.

[0018] In a preferred embodiment, in step 1, the reducing agent includes glucose.

[0019] In a preferred embodiment, in step 1, the mass volume ratio of the reducing agent to oleylamine is 0.1 g:(5-10) ml; preferably, the mass volume ratio of the reducing agent to oleylamine is 0.2 g:15 ml.

[0020] In a preferred embodiment, in step 1, the ultrasonic mixing treatment method is: ultrasonic treatment at 50-200W for 1-2 hours to obtain a uniformly mixed precursor solution.

[0021] In a preferred embodiment, in step 2, the inert gas includes nitrogen or argon.

[0022] In a preferred embodiment, in step 2, the heating temperature is 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, or 240°C.

[0023] In a preferred embodiment, in step 2, the insulation time is 3-6 hours; preferably, the insulation time is 4 hours or 5 hours.

[0024] In a preferred embodiment, in step three, the washing method comprises ultrasonic cleaning with ethanol for 2-4 times; and the drying method comprises drying in a forced air oven at 50-70° C. for 1-8 hours.

[0025] The present invention also provides a five-element non-noble metal high entropy alloy catalyst prepared by any of the above methods.

[0026] The present invention also provides the application of the five-element non-precious metal high-entropy alloy catalyst prepared by any of the methods described above in the fields of flexible zinc-air batteries, flexible electronic devices, and flexible wearable devices.

[0027] In a preferred embodiment, in the flexible zinc-air battery, Fe-NC and a five-element non-precious metal high entropy alloy prepared by any one of the methods described above are mixed as air cathode catalysts; preferably, the mass ratio of the Fe-NC and the prepared five-element non-precious metal high entropy alloy is 1:(0.5-1.5); more preferably, the mass ratio of the Fe-NC and the prepared five-element non-precious metal high entropy alloy is 1:1.

[0028] In a preferred embodiment, the preparation method of the Fe-NC comprises the following steps:

[0029] S1 uses potassium citrate as the raw material to prepare porous carbon by pyrolysis: 3-7g of potassium citrate is heated to 700-900℃ in a tube furnace with Ar protective gas at 2-4℃ / min and kept warm for 0.5-1.5h; after cooling to room temperature, the resulting solid is acid-leached with 0.3-0.7M H2SO4 solution for 12h overnight, then repeatedly washed with deionized water until neutral, and the precipitate is dried at 50-70℃ to obtain black porous carbon as a support;

[0030] S2: 0.5-1 mmol FeCl3·6H2O and 0.5-1 mmol tannic acid are mixed in 25-75 ml of deionized water solution, and magnetic stirring is performed for 10-20 minutes to allow the iron ions and tannic acid to fully react. Then, 20-40 mg of the porous carbon obtained in step S1 is added to the solution, and ultrasonication is performed for 20-40 minutes to fully mix, followed by impregnation for 12 hours. The reactants are then poured into a centrifuge tube and centrifuged at a speed of 3000-5000 r / min and washed with deionized water. The supernatant is discarded, and the obtained solid sample is placed in a blast drying oven at 50-70°C for 5-7 hours, and after drying, it is ground to obtain a powder.

[0031] S3: The precursor powder obtained in step S2 and melamine are thoroughly mixed and ground in a mass ratio of 1:(4-6); the powder is then placed in a porcelain boat in a flowing inert atmosphere, heated at a rate of 4-6°C / min, and kept at a target holding temperature of 700-900°C for 1-3 hours. After the temperature drops to room temperature, the powder is taken out and ground to obtain the black powder.

[0032] In a preferred embodiment, in the flexible zinc-air battery, zinc foil serves as the negative electrode, polypropylene-based hydrogel soaked in zinc acetate and / or potassium hydroxide electrolyte serves as the quasi-solid electrolyte, and carbon cloth coated with a cathode catalyst serves as the positive electrode; preferably, the electrolyte contains 6M potassium hydroxide and 0.2M zinc acetate, and the immersion time is 12-36h.

[0033] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0034] 1. The present invention uses a low-temperature liquid-phase reduction method to prepare metal alloy materials, which only requires a relatively low heating temperature (below 250°C) to synthesize the catalyst, without the need for traditional high-temperature and high-pressure conditions and subsequent complex and high-cost conditions such as a reducing atmosphere.

[0035] 2. In the present invention, octadecyltrimethylammonium bromide is used as a surfactant to affect the kinetics of the metal reduction reaction, slow down the reaction rate, and form a single-phase structure; at the same time, the size and morphology of the particles can be controlled to prevent agglomeration, thereby increasing the specific surface area and promoting the catalytic reaction, thereby improving metal utilization.

[0036] 3. The overall operation steps of the present invention are simple, and the cost of raw materials and energy consumption is low, and it is particularly suitable for large-scale industrial production and preparation.

[0037] 4. The FeCoNiCuMo non-noble metal high entropy alloy catalyst obtained in the present invention has a multi-element mixed valence state characteristic. In alkaline electrolyte, at 100mA / cm 2 After 650 hours of continuous operation at the same current density, the overpotential did not show a significant increase, which significantly improved the stability of the oxygen evolution reaction.

[0038] 5. The FeCoNiCuMo non-precious metal high-entropy alloy catalyst obtained in this invention exhibited excellent mechanical durability and electrochemical stability in a flexible zinc-air battery. The battery maintained normal charge and discharge performance under various bending angles, and showed no voltage rise during a charging voltage platform test lasting more than 35 hours, fully demonstrating its potential for application in flexible energy storage devices and, consequently, in flexible wearable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] These and / or other aspects and advantages of the present invention will become more apparent and more readily understood from the following detailed description of embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0040] Figure 1 is a transmission electron microscopy (TEM) image of the catalyst material prepared in Example 1 of the present invention;

[0041] Figure 2 1 is the X-ray diffraction pattern (XRD) of the catalyst materials prepared in Example 1 of the present invention and Comparative Example 1;

[0042] Figure 3 is a scanning electron microscope image (SEM) of the catalyst material prepared in Example 1 of the present invention;

[0043] Figure 4 is a scanning electron microscope image (SEM) of the catalyst material prepared in Comparative Example 2 of the present invention;

[0044] Figure 5 The linear sweep voltammetry comparison curves of the catalyst materials prepared in Examples 1-5 of the present invention in 1M KOH electrolyte are shown;

[0045] Figure 6 The catalyst material prepared in Example 1 of the present invention and the commercial RuO2 catalyst are 2 LSV polarization curves before and after 24h Et test at a current density of ;

[0046] Figure 7 1 is a linear sweep voltammetry comparison curve of the five-element high entropy alloy catalyst material prepared in Example 1 of the present invention and the four-element alloy catalyst material prepared in Comparative Example 1 in 1M KOH electrolyte;

[0047] Figure 8 The five-element high entropy alloy catalyst material prepared in Example 1 of the present invention, the four-element alloy catalyst material prepared in Comparative Example 1 and the commercial RuO2 catalyst were tested at 100 mA / cm 2 Et test curve under current density;

[0048] Figure 9 The catalyst material prepared in Example 1 of the present invention is 100mA / cm in 1M KOH electrolyte. 2 Constant current timing curve under current density;

[0049] Figure 10 1. (a) Each component and (b) The overall structural device diagram of the flexible zinc-air battery of Application Example 2 of the present invention;

[0050] Figure 11 The charge-discharge cycle curves of a flexible zinc-air battery assembled with an air cathode obtained by mixing the catalyst material prepared in Example 1 of the present invention with an Fe-NC non-precious metal oxygen reduction catalyst in equal proportions at different bending angles are shown;

[0051] Figure 12 This is the charge and discharge cycle curve of a flexible zinc-air battery assembled with an air cathode obtained by mixing the catalyst material prepared in Example 1 of the present invention with an Fe-NC non-noble metal oxygen reduction catalyst in equal proportions. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that the protection scope of the present invention is not limited to the specific embodiments.

[0053] The embodiments of the present invention provide a five-element non-precious metal high-entropy alloy catalyst, a preparation method thereof, and an application in a zinc-air battery, thereby solving the problems in the prior art of complex multi-element high-entropy alloy synthesis process, high energy consumption, low stability and low activity of the obtained high-entropy alloy catalyst.

[0054] The technical solution of this application is described in detail below through specific embodiments:

[0055] Unless otherwise specified, the technical means used in the present invention are conventional means well known to those skilled in the art. The various raw materials, reagents, instruments, and equipment used in the present invention can be purchased from the market or prepared by existing methods. Unless otherwise specified, the reagents used in the present invention are of analytical grade.

[0056] The preparation method of Fe-NC used in the application example of the present invention comprises the following steps:

[0057] S1 uses potassium citrate as raw material to prepare porous carbon by pyrolysis: 5g of potassium citrate is heated to 800℃ at 3℃ / min in a tube furnace with Ar protective gas and kept warm for 1h; after cooling to room temperature, a black solid residue is obtained; the obtained solid is acid-leached with 0.5M H2SO4 solution for 12h overnight, then repeatedly washed with deionized water until neutral, and the precipitate is dried at 60℃ to obtain black porous carbon as a support;

[0058] S2: 0.75 mmol FeCl3·6H2O and 0.75 mmol tannic acid were mixed in 50 ml of deionized water solution and magnetically stirred for 15 minutes to allow the iron ions and tannic acid to fully react. Then, 30 mg of the porous carbon obtained in step S1 was added to the solution, and ultrasonicated for 30 minutes to fully mix. Then, the mixture was impregnated for 12 hours. The reactants were then poured into a centrifuge tube and centrifuged at 4000 r / min and washed with deionized water. The supernatant was discarded, and the obtained solid sample was placed in a blast drying oven and dried at 60°C for 6 hours. After drying, it was ground to obtain a powder.

[0059] S3: The precursor powder obtained in step S2 and melamine are thoroughly mixed and ground in a mass ratio of 1:5; the powder is then placed in a porcelain boat in a flowing inert atmosphere, heated at a target holding temperature of 800°C at a heating rate of 5°C / min for 2 hours, taken out after the temperature drops to room temperature, and the resulting black powder is ground to obtain a catalyst named Fe-NC.

[0060] Example 1

[0061] Step 1: Dissolve 0.8 mmol each of Fe(C5H7O2)3, Co(C5H7O2)2, Ni(C5H7O2)3, Cu(C5H7O2)3 and Mo(CO)6 in 15 mL of oleylamine (OAm), add 0.1 g of octadecyltrimethylammonium bromide (STAB) and 0.2 g of glucose, and use an ultrasonic cleaner to ultrasonically treat the mixed solution at a power of 100 W for 2 h to obtain a uniformly mixed precursor solution.

[0062] Step 2: Place the precursor solution of step 1 in a round-bottom flask, fill the flask with inert gas (N2) for protection, and heat at 210°C for 5h to generate a black precipitate.

[0063] Step 3: The reaction product of step 2 was ultrasonically cleaned with ethanol three times and then dried in a 60° C. forced air oven for 3 h to obtain a high entropy alloy catalyst FeCoNiCuMo HEAs.

[0064] The transmission electron microscopy image of the high entropy alloy catalyst prepared in this example is as follows Figure 1 As shown in the TEM image, it can be observed that the particle size of the catalyst is about 80 nm. This nanoscale microstructure can give the catalyst a larger specific surface area to expose more catalyst active sites and provide more reaction sites for the reactants and intermediates of the OER catalytic reaction.

[0065] Comparative Example 1

[0066] The only difference from Example 1 is that hexacarbonyl molybdenum Mo(CO)6 is not added in step 1, and the other steps and raw materials are the same as those in Example 1.

[0067] Figure 2 The X-ray diffraction patterns of the five-element high-entropy alloy catalyst material prepared in Example 1 and the four-element alloy catalyst material prepared in Comparative Example 1 were used to characterize the crystal structure of the alloy catalyst by XRD. From the XRD pattern results, the alloy samples all showed the FCC structure of the iron-nickel alloy (PDF#47-1417), and the diffraction peaks at 43.3°, 50.4° and 74.1° corresponded to the (111), (200) and (220) crystal planes, respectively. The addition of Mo resulted in a higher crystallinity of the high-entropy alloy catalyst, which enhanced the mechanical stability and corrosion resistance of the material. The ordered lattice structure reduced electron scattering, improved the overall conductivity of the material, and facilitated the rapid transfer of charge on the catalyst surface, thereby reducing the overpotential.

[0068] Comparative Example 2

[0069] The only difference from Example 1 is that STAB surfactant is not added in step 1, and the other steps and raw materials are the same as those in Example 1.

[0070] The scanning electron microscope images of the materials prepared in Example 1 and Comparative Example 2 are shown as follows: Figure 3 and Figure 4 As shown in the figure, it can be seen that the addition of surfactant STAB can effectively reduce the agglomeration of the catalyst, thereby obtaining a catalyst with a larger specific surface area.

[0071] Example 2

[0072] The only difference from Example 1 is that the ultrasonication time in step 1 is 1 h, and the other steps and raw materials are the same as those in Example 1.

[0073] Example 3

[0074] The only difference from Example 1 is that the heating temperature in step 2 is 180° C., and the other steps and raw materials are the same as those in Example 1.

[0075] Example 4

[0076] The only difference from Example 1 is that the heating temperature in step 2 is 230° C., and the other steps and raw materials are the same as those in Example 1.

[0077] Example 5

[0078] The only difference from Example 1 is that the heating time in step 2 is 3 h, and the other steps and raw materials are the same as those in Example 1.

[0079] Application Example 1

[0080] OER performance test: In a three-electrode system at room temperature (a high-purity graphite electrode was used as the counter electrode, an Ag / AgCl reference electrode filled with saturated KCl electrolyte was used as the reference electrode, and a nickel foam coated with a catalyst was used as the working electrode), 1M KOH electrolyte was used to study the electrocatalytic OER activity of the five-element high-entropy alloy catalyst FeCoNiCuMo HEAs prepared in Example 1, the five-element high-entropy alloy catalyst prepared in Examples 2-5, the four-element high-entropy alloy catalyst prepared in Comparative Example 1, and the commercial RuO2 catalyst (all after CV activation). The measured results were all calculated using the formula (E RHE =E (Ag / AgCl) +0.059*pH+0.198) is converted to a reversible hydrogen electrode (pH of 1MKOH is 14), and the result is as follows Figure 5-9 shown.

[0081] Depend on Figure 5 It can be seen that the FeCoNiCuMo HEAs obtained by ultrasonic treatment for 2 h and heating at 210 °C for 5 h have the best electrocatalytic OER performance, and only an overpotential of 340 mV is required to achieve 100 mA / cm 2 The current density is significantly lower than the overpotential required at 180℃ (427mV), 230℃ (390mV), ultrasound for 1h (370mV) and insulation for 3h (360mV).

[0082] Figure 6 By comparing the FeCoNiCuMo HEAs and RuO2 catalysts at 100mA / cm 2 From the LSV polarization curves before and after the 24h Et test at a current density of 1.54 Å, it can be found that the FeCoNiCuMo HEAs only showed a slight attenuation of about 10 mV, while the overpotential of the commercial RuO2 catalyst increased by about 50 mV.

[0083] Figure 7 By comparing the linear sweep voltammetry curves of the five-element high entropy alloy catalyst material prepared in Example 1 and the four-element alloy catalyst material prepared in Comparative Example 1 in 1M KOH electrolyte, it can be found that the OER catalytic activity of FeCoNiCuMo HEAs is much higher than that of the FeCoNiCu four-element alloy catalyst in Comparative Example 1.

[0084] Figure 8 At 100mA / cm 2 In the Et test at a current density of , there was almost no OER activity decay after 90,000 s, and the prepared five-element high entropy alloy catalyst showed better stability than the precious metal RuO2 catalyst.

[0085] Figure 9 Through 650h at 100mA / cm2 In the Et test under a current density of , the required current was stable and no obvious overpotential increase occurred, indicating that the surface catalyst performance was stable.

[0086] Application Example 2

[0087] Zinc-air battery testing: Reference Figure 10 Diagram of a zinc-air battery setup. It uses catalyst-coated carbon cloth as the positive electrode, the carbon cloth as the current collector, polished zinc foil as the negative electrode, and hydrogel as the electrolyte. The air cathode, hydrogel electrolyte, and zinc foil are sandwiched between two sheets of aluminum-plastic film. A heating plate is then used to heat and press the surrounding aluminum-plastic film to seal the battery. A small hole is punctured on one side of the air cathode to allow air in.

[0088] The zinc foil negative electrode is made by sanding the side of a commercially available pure zinc sheet close to the electrolyte with sandpaper to remove the surface oxide and expose the Zn metal. A commercial acrylate-based gel is used as the quasi-solid electrolyte for the flexible zinc-air battery. The commercially available gel electrolyte is soaked in a solution of 6M KOH and 0.2M Zn(OAc)2 for 24 hours. The hydrogel absorbs the electrolyte and swells, increasing its volume, resulting in a quasi-solid electrolyte that serves as a catalyst for the flexible zinc-air battery. Before use, any residual electrolyte on the hydrogel surface needs to be wiped off with a non-woven cloth.

[0089] Fe-NC and HEAs prepared in Example 1 were used as ORR and OER catalysts respectively (commercial catalysts were used as comparisons). 2 mg of OER catalyst and 2 mg of ORR catalyst were mixed in a solution of 80 μL + 720 μL of ethanol and homogenized by ultrasound. At the same time, a circular vent with a diameter of 1 cm in the zinc-air battery device was used as the effective loading area of ​​the catalyst. 315 μL of ink was applied to the area, and the final loading of OER and ORR was 1 mg / cm. 2 of the air cathode.

[0090] Specific performance test results are as follows Figure 11-12 As shown, Figure 11 The results of constant current charge and discharge tests of FeCoNiCuMo HEAs+Fe-NC based flexible zinc-air battery at 0°, 30° and 90° bending angles are shown. It can be seen that even during the bending process and after returning to the initial state, the battery has a constant current of 5 mA / cm 2 The results show that the five-element high entropy alloy catalyst prepared by the present invention can still maintain a stable charging (1.9V) and discharging (1.1V) platform under the condition of high voltage, which shows that the five-element high entropy alloy catalyst prepared by the present invention has application potential in the flexible electronics and wearable device markets.

[0091] Figure 12 In the 5mW / cm 2Under the current density, the FeCoNiCuMo HEAs+Fe-NC based flexible zinc-air battery achieved a stable charge and discharge test of more than 30 hours, and the charging voltage platform was stable at around 1.95V, which is better than the Pt / C-RuO2 benchmark flexible zinc-air battery.

[0092] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to make and utilize a variety of exemplary embodiments of the invention and various options and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing a five-element non-noble metal high entropy alloy catalyst, characterized in that: The five-element non-precious metal high-entropy alloy catalyst is synthesized in one step by combining metal salts containing Fe, Co, Ni, Cu, and Mo with a surfactant and a reducing agent at a low temperature of 150-250°C; its crystal structure is a face-centered cubic single-phase solid solution structure, and its average particle size is 80-90nm.

2. The method for preparing a five-element non-noble metal high entropy alloy catalyst according to claim 1, wherein: The following steps are involved: Step 1: Dissolve Fe(C5H7O2)3, Co(C5H7O2)2, Ni(C5H7O2)3, Cu(C5H7O2)3 and Mo(CO)6 in oleylamine, add surfactant and reducing agent, and mix by ultrasonication to obtain a precursor solution; Step 2: Heat the precursor solution from step 1 to 150-250°C under inert gas protection and allow to react for a period of time to generate solid particles; Step 3: Wash and dry the reaction product of step 2 to obtain a high entropy alloy catalyst.

3. The method for preparing a five-element non-noble metal high entropy alloy catalyst according to claim 2, wherein: In step 1, the molar ratio of Fe(C5H7O2)3, Co(C5H7O2)2, Ni(C5H7O2)3, Cu(C5H7O2)3 and Mo(CO)6 is 1:(0.8-1.2):(0.8-1.2):(0.8-1.2).

4. The method for preparing a five-element non-noble metal high entropy alloy catalyst according to claim 2, wherein: In step 1, the volume ratio of the total amount of Fe(C5H7O2)3, Co(C5H7O2)2, Ni(C5H7O2)3, Cu(C5H7O2)3 and Mo(CO)6 to oleylamine is 2mmol:(6-9)ml.

5. The method for preparing a five-element non-noble metal high entropy alloy catalyst according to claim 2, wherein: In step 1, the surfactant includes octadecyltrimethylammonium bromide; the mass volume ratio of the surfactant to oleylamine is 0.1 g: (10-20) ml.

6. The method for preparing a five-element non-noble metal high entropy alloy catalyst according to claim 2, wherein: In step 1, the reducing agent includes glucose; the mass volume ratio of the reducing agent to oleylamine is 0.1 g: (5-10) ml.

7. The method for preparing a five-element non-noble metal high entropy alloy catalyst according to claim 2, wherein: In step 2, the heat preservation reaction time is 3-6 hours.

8. A five-element non-noble metal high entropy alloy catalyst prepared by the method according to any one of claims 1 to 7.

9. Application of the five-element non-precious metal high entropy alloy catalyst prepared by the method according to any one of claims 1 to 7 in the fields of flexible zinc-air batteries, flexible electronic devices, and flexible wearable devices.

10. The use of the method according to claim 9 in a flexible zinc-air battery, wherein: Fe-NC and a five-element non-noble metal high entropy alloy prepared by the method according to any one of claims 1 to 7 are mixed as an air cathode catalyst.

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