Star-shaped Co / CeO2-coated NC composite material as well as preparation method and application thereof
By preparing star-shaped Co/CeO2@NC composite materials as catalysts, the high cost problem of precious metal catalysts in rechargeable zinc-air batteries was solved, low-cost and high-performance ORR/OER performance was achieved, and the commercialization process of zinc-air batteries was promoted.
Patent Information
- Application Number
- CN202510928862.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-07
- Publication Date
- 2025-10-10
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The large-scale application of existing rechargeable zinc-air batteries is limited by the high cost and scarcity of precious metal catalysts, and the kinetic behavior and electrochemical stability of air cathode materials are insufficient, affecting the battery's rechargeability and energy conversion efficiency.
A star-shaped Co/CeO2@NC composite material was used as the cathode catalyst. By adding hexadecyltrimethylammonium bromide as a surfactant during the preparation process, a star-shaped structure was formed to improve the ORR/OER performance and avoid the use of precious metals.
It achieves excellent ORR/OER performance under alkaline conditions, improves the performance of rechargeable zinc-air batteries, has good application prospects, and outperforms precious metal-based catalysts.
Smart Images
Figure CN120767338A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of rechargeable zinc-air batteries, and in particular relates to a star-shaped Co / CeO2@NC composite material and a preparation method and application thereof. Background Art
[0002] Rechargeable zinc-air batteries (ZABs) are considered to be highly promising next-generation energy conversion devices due to their high specific energy density, low cost, and high safety. However, the sluggish kinetic behavior and poor electrochemical stability of air cathode materials have seriously hindered their commercialization, resulting in insufficient battery rechargeability and low energy conversion efficiency. Currently, platinum-based and ruthenium / iridium-based oxide catalysts have been used to promote the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), respectively, but the high cost and scarcity of these precious metal catalysts have greatly limited the large-scale application of ZABs. Therefore, the development of non-precious metal electrocatalysts that are abundant on Earth, low-cost, and have excellent bifunctional properties is key to promoting the commercialization of rechargeable ZABs. Summary of the Invention
[0003] In order to solve the above technical problems, the present invention proposes a star-shaped Co / CeO2@NC composite material and its preparation method and application.
[0004] To achieve the above objectives, the present invention provides the following technical solutions:
[0005] The present invention provides a preparation method of a star-shaped Co / CeO2@NC composite material, comprising the following steps: adding a soluble zinc salt, a soluble cobalt salt, a soluble cerium salt, dimethylimidazole and hexadecyltrimethylammonium bromide into a solvent, reacting under stirring conditions, washing and drying the product after the reaction, and then calcining (to carbonize the material) to obtain the star-shaped Co / CeO2@NC composite material.
[0006] The principle behind this invention is that silica is not used as a template when preparing the star-shaped Co / CeO2@NC composite material. Instead, cetyltrimethylammonium bromide, a surfactant, is added to the material, transforming the composite material into a star-shaped morphology. This star-shaped Co / CeO2@NC composite material exhibits better ORR performance than non-star-shaped composites. The Co / CeO2@NC composite material prepared by this invention can be used in zinc-air batteries and exhibits promising performance and application prospects.
[0007] Furthermore, the solvent is water.
[0008] Further, the use amount ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, the dimethylimidazole and the cetyltrimethylammonium bromide is 2 mmol:(0.85-0.9) mmol:(0.1-0.2) mmol:54.8 mmol:10 mg.
[0009] For example, the use amount ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, the dimethylimidazole and the cetyltrimethylammonium bromide is 2 mmol:0.8 mmol:0.2 mmol:54.8 mmol:10 mg.
[0010] For example, the use amount ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, the dimethylimidazole and the cetyltrimethylammonium bromide is 2 mmol:0.85 mmol:0.15 mmol:54.8 mmol:10 mg.
[0011] For example, the use amount ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, the dimethylimidazole and the cetyltrimethylammonium bromide is 2 mmol:0.9 mmol:0.1 mmol:54.8 mmol:10 mg.
[0012] For example, the soluble zinc salt is zinc nitrate, the soluble cobalt salt is cobalt nitrate, and the soluble cerium salt is cerium nitrate.
[0013] Further, the temperature for the reaction under stirring is 25±2℃, and the time is 3 h.
[0014] Further, the drying temperature is 60-70℃.
[0015] Further, the calcination temperature is 810-1100℃, and the time is 2 h; the calcination is carried out in an inert gas atmosphere.
[0016] For example, the inert gas atmosphere is argon.
[0017] Further, the calcination temperature is 810℃, 910℃ or 1100℃, and preferably 910℃.
[0018] The application also provides a star-shaped Co / CeO2@NC composite material prepared according to the above method.
[0019] The star-shaped Co / CeO2@NC composite material has excellent ORR / OER performance under alkaline conditions.
[0020] The application also provides application of the above star-shaped Co / CeO2@NC composite material in a rechargeable zinc-air battery, and the star-shaped Co / CeO2@NC composite material is used as a cathode catalyst.
[0021] Compared with the prior art, the present invention has the following advantages and technical effects:
[0022] The preparation method of the present invention is simple, and the star-shaped Co / CeO2@NC composite material has excellent ORR / OER performance under alkaline conditions. In addition, the star-shaped Co / CeO2@NC composite material prepared by the present invention can be used to prepare rechargeable zinc-air batteries, which have better performance than precious metal-based rechargeable zinc-air batteries and have good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:
[0024] Figure 1 This is the powder diffraction pattern of the Co / CeO2@NC composite material prepared in Example 1;
[0025] Figure 2 This is the powder diffraction pattern of the Co / CeO2@NC composite material prepared in Example 2-Example 3;
[0026] Figure 3 CV curves, LSV plots, Tafel plots, and hydrogen peroxide yield (H2O2%) and electron transfer number (n) plots of the ORR of the Co / CeO2@NC composite materials prepared in Examples 1 to 3, wherein a is a CV curve plot, b is an LSV plot, c is a Tafel plot, and d is a hydrogen peroxide yield (H2O2%) and electron transfer number (n) plot;
[0027] Figure 4 CV curves, LSV plots, Tafel plots, and hydrogen peroxide yield (H2O2%) and electron transfer number (n) plots of the ORR of the Co / CeO2@NC composite materials prepared in Examples 1 and 4-5, wherein a is a CV curve plot, b is an LSV plot, c is a Tafel plot, and d is a plot of hydrogen peroxide yield (H2O2%) and electron transfer number (n);
[0028] Figure 5 2 is a comparison chart of the ORR performance of the star-shaped Co / CeO2@NC composite material prepared in Example 1 and the non-star-shaped Co / CeO2@NC composite material prepared in Comparative Example 1;
[0029] Figure 6 Scanning electron microscope (SEM) images, high-resolution transmission electron microscope (TEM) images, and high-angle annular dark-field transmission electron microscope images of the Co / CeO2@NC composite material prepared in Example 1, wherein a is an SEM image, b is a TEM image, and c is a high-angle annular dark-field transmission electron microscope image;
[0030] Figure 7 LSV diagrams of ORR and OER of the Co / CeO2@NC composite material prepared in Example 1, Co@NC prepared in Comparative Example 2, CeO2@NC prepared in Comparative Example 3, and NC prepared in Comparative Example 4, where a is the LSV diagram of ORR and b is the LSV diagram of OER;
[0031] Figure 8 The stability diagrams of ORR and OER of the Co / CeO2@NC composite material prepared in Example 1, where a is the stability diagram of ORR and b is the stability diagram of OER;
[0032] Figure 9 The open circuit voltage and maximum power density diagrams of the liquid zinc-air battery prepared using the Co / CeO2@NC composite material in Example 1, where a is the open circuit voltage diagram and b is the maximum power density diagram;
[0033] Figure 10 The liquid zinc-air battery prepared by using the Co / CeO2@NC composite material in Example 1 was tested at a current density of 5 mA·cm -2 Stability diagram when ;
[0034] Figure 11 The open circuit voltage, maximum power density and the current density of the solid-state flexible zinc-air battery prepared by the Co / CeO2@NC composite material in Example 1 are shown in FIG. -2 The stability diagram of the current density is 2 mA·cm, where a is the open circuit voltage, b is the maximum power density diagram, and c is the current density of 2 mA·cm -2 Stability diagram when ;
[0035] Figure 12 This is the SEM image of the non-star-shaped structure material prepared in Comparative Example 1. DETAILED DESCRIPTION
[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0037] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.
[0038] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.
[0039] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.
[0040] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.
[0041] An embodiment of the present invention provides a method for preparing a star-shaped Co / CeO2@NC composite material, comprising the following steps: adding a soluble zinc salt, a soluble cobalt salt, a soluble cerium salt, dimethylimidazole, and hexadecyltrimethylammonium bromide to a solvent, reacting under stirring, washing and drying the product after the reaction, and then calcining it to obtain the star-shaped Co / CeO2@NC composite material. A preferred method for preparing the star-shaped Co / CeO2@NC composite material is as follows: accurately weighing the raw materials in proportion, adding the soluble zinc salt, soluble cobalt salt, soluble cerium salt, and hexadecyltrimethylammonium bromide to water to form solution a; adding dimethylimidazole to water to form solution b; mixing solutions a and b, reacting by stirring at room temperature, washing the product with ethanol and deionized water, sequentially, after the reaction, and drying to obtain Ce-ZIF67; and calcining the Ce-ZIF67 under a flowing argon atmosphere to obtain the Co / CeO2@NC material.
[0042] When preparing the Co / CeO2@NC composite material, the present invention adds cetyltrimethylammonium bromide, which serves as a surfactant and changes the morphology of the Co / CeO2@NC composite material into a star shape. The ORR performance of the star-shaped Co / CeO2@NC composite material is better than that of the non-star-shaped one.
[0043] In a preferred embodiment of the present invention, the solvent is water.
[0044] In a preferred embodiment of the present application, the molar ratio of the soluble zinc salt to the sum of the soluble cobalt salt and the soluble cerium salt is 2:1. The amount ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, dimethylimidazole and cetyltrimethylammonium bromide is 2 mmol:(0.85-0.9) mmol:(0.1-0.2) mmol:54.8 mmol:10 mg.
[0045] For example, the amount ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, dimethylimidazole and cetyltrimethylammonium bromide is 2 mmol:0.8 mmol:0.2 mmol:54.8 mmol:10 mg.
[0046] For example, the amount ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, dimethylimidazole and cetyltrimethylammonium bromide is 2 mmol:0.85 mmol:0.15 mmol:54.8 mmol:10 mg.
[0047] For example, the amount ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, dimethylimidazole and cetyltrimethylammonium bromide is 2 mmol:0.9 mmol:0.1 mmol:54.8 mmol:10 mg.
[0048] In a preferred embodiment of the present application, the soluble zinc salt is zinc nitrate, the soluble cobalt salt is cobalt nitrate, and the soluble cerium salt is cerium nitrate.
[0049] In a preferred embodiment of the present application, the reaction is carried out at a temperature of 25±2℃ under stirring for 3h.
[0050] In a preferred embodiment of the present application, the drying temperature is 60-70℃.
[0051] In a preferred embodiment of the present application, the calcination temperature is 810-1100℃, and the calcination time is 2h; the calcination is carried out in an inert gas atmosphere. For example, the calcination temperature is 810℃, 910℃ or 1100℃. For example, the inert gas atmosphere is argon.
[0052] The embodiment of the present application also provides a star-shaped Co / CeO2@NC composite material prepared according to the above method.
[0053] The star-shaped Co / CeO2@NC composite material of the present application is a bifunctional catalyst, which has both ORR performance and OER performance under alkaline conditions, and can improve the performance of rechargeable zinc-air batteries.
[0054] The star-shaped Co / CeO2@NC composite material provided by the embodiment of the present application can be used to prepare rechargeable zinc-air batteries, wherein the star-shaped Co / CeO2@NC composite material is used as a cathode catalyst.
[0055] Unless otherwise specified, the room temperature in the present application is 25±2℃.
[0056] The raw materials used in the embodiments of the present application are all commercially available.
[0057] In the present application, the saturated Ag / AgCl electrode is obtained by immersing the AgCl-coated silver wire into saturated KCl solution.
[0058] It should be noted that the parts not described in detail in the present application are all conventional operation means in the art and are not the focus of the present application.
[0059] The technical solutions of the present application are further illustrated by the following examples.
[0060] Example 1
[0061] Preparation of the precursor Ce-ZIF67: 2 mmol of zinc nitrate hexahydrate, 10 mg of cetyltrimethylammonium bromide, 0.85 mmol of cobalt nitrate hexahydrate and 0.15 mmol of cerium nitrate hexahydrate (the total amount of cobalt nitrate hexahydrate and cerium nitrate hexahydrate is controlled to be 1 mmol) are added into 200 mL of deionized water to form solution a; 54.8 mmol of dimethylimidazole is dissolved in 80 mL of deionized water to form solution b; solution a and solution b are mixed, stirred at room temperature for 3 hours, washed with ethanol and deionized water in turn, and then dried at 60℃ for 12 hours to obtain Ce-ZIF67;
[0062] Carbonization: the Ce-ZIF67 is placed in a muffle furnace, heated to 910℃ at a heating rate of 5℃ / min under the condition of flowing argon atmosphere, and reacted for 2 hours to obtain the Co / CeO2@NC composite material.
[0063] The powder diffraction pattern of the Co / CeO2@NC composite material prepared in this example is shown in Figure 1 , which proves the successful preparation of Co / CeO2@NC.
[0064] Example 2
[0065] The same as Example 1, except that the amount of cobalt nitrate hexahydrate is 0.9 mmol and the amount of cerium nitrate hexahydrate is 0.1 mmol.
[0066] Example 3
[0067] The same as Example 1, except that the amount of cobalt nitrate hexahydrate is 0.8 mmol and the amount of cerium nitrate hexahydrate is 0.2 mmol.
[0068] The powder diffraction pattern of the Co / CeO2@NC composite material prepared in Example 2-Example 3 is shown in Figure 2The successful preparation of Co / CeO2@NC is proved.
[0069] Example 4
[0070] The same as Example 1, except that the carbonization temperature is 810°C.
[0071] Example 5
[0072] The same as Example 1, except that the carbonization temperature is 1100°C.
[0073] Comparative Example 1
[0074] The same as Example 1, except that no cetyltrimethylammonium bromide is added when preparing the precursor Ce-ZIF67.
[0075] The final product of this comparative example is a Co / CeO2@NC composite material with non-starlike structure, denoted as No-Starlike.
[0076] Comparative Example 2
[0077] The same as Example 1, except that no cerium nitrate is added.
[0078] The final product of this comparative example is a Co@NC composite material.
[0079] Comparative Example 3
[0080] The same as Example 1, except that no cobalt nitrate is added.
[0081] The final product of this comparative example is a CeO2@NC composite material.
[0082] Comparative Example 4
[0083] The same as Example 1, except that no cerium nitrate and no cobalt nitrate are added.
[0084] The final product of this comparative example is a NC material.
[0085] Electrochemical performance test:
[0086] The electrocatalytic performance of each material as a cathode catalyst was evaluated using a standard three-electrode system on an electrochemical workstation (CHI760E). The RDE (rotating disc electrode) loaded with catalyst ink was used as the working electrode, a graphite rod was used as the counter electrode, and a saturated Ag / AgCl electrode was used as the reference electrode. The commercial Pt / C (loading: 0.1 mg·cm -2) behavior was used as a reference. A 0.1 M KOH solution saturated with N2 / O2 was used as the electrolyte. The measured potential was calibrated according to the following equation: E(RHE) = E(Ag / AgCl) + 0.059*pH + 0.197 V, where E(RHE) is the potential relative to the reversible hydrogen electrode (RHE) (V); and E(Ag / AgCl) is the raw potential measured with an Ag / AgCl reference electrode (V).
[0087] To prepare a thin-film working electrode (RDE loaded with catalyst ink), 2 mg of each material sample prepared in each Example or Comparative Example was ultrasonically dispersed with 5 μL of a 5 wt.% Nafion solution in 100 mL of deionized water and 200 mL of isopropanol to form a uniform ink. Then, 25 μL of the thoroughly dispersed catalyst ink was suspended on a pre-polished RDE and dried before measurement. As a control, Pt / C was prepared under the same conditions. The specific method is as follows:
[0088] 2 mg of Co / CeO2@NC material was weighed and dissolved in 200 mL of isopropanol, 100 mL of deionized water and 5 μL of Nafion solution (5 wt.%). Ultrasonic dispersion was performed and then dropped on an area of 1 cm 2 A flexible solid-state zinc-air battery (ZAB) was assembled on a carbon cloth loaded with catalyst ink as the air cathode. The flexible solid-state zinc-air battery was assembled as follows: 5 g of polyvinyl alcohol (PVA) was dissolved in 50 mL of deionized water and stirred vigorously (400 rpm) at 90°C for 1.5 hours. To this mixture was added 5 mL of a mixed solution of 18 M KOH and 0.02 M Zn(CH3COO)2. The solution was stirred vigorously (400 rpm) for 30 minutes to form a homogeneous, transparent solution. The solution was then frozen in a refrigerator and thawed at room temperature for later use, yielding a polymer gel. A solid-state flexible ZAB (ZAB) was assembled using carbon cloth loaded with catalyst ink as the air cathode, nickel foam as the conductive current collector, the polymer gel as the electrolyte, and zinc foil as the anode. The polarization curve, open-circuit voltage, and power density of the ZAB were measured using an electrochemical workstation (CHI760E). The stability and galvanostatic charge-discharge curves of the ZAB were recorded using a LAND battery testing system (BT2016A).
[0089] The ORR CV curves, LSV graphs, Tafel graphs, hydrogen peroxide yield (H2O2%) and electron transfer number (n) of the Co / CeO2@NC composite materials prepared in Examples 1 to 3 are shown in FIG. Figure 3As shown in the figure, it is shown that the Co / CeO2@NC composite material with a molar ratio of 0.85 / 0.15 has the best ORR performance. Therefore, the optimal preparation ratio of Co / CeO2@NC composite material is 0.85 mmol of cobalt nitrate and 0.15 mmol of cerium nitrate.
[0090] The ORR CV curves, LSV graphs, Tafel graphs, hydrogen peroxide yield (H2O2%) and electron transfer number (n) of the Co / CeO2@NC composite materials prepared in Example 1, Example 4-Example 5 are shown in FIG. Figure 4 As shown in the figure, it shows that the ORR performance of the Co / CeO2@NC composite material prepared at 910℃ is the best, so the optimal calcination temperature of the Co / CeO2@NC composite material is 910℃.
[0091] The ORR performance comparison of the star-shaped Co / CeO2@NC composite material prepared in Example 1 and the non-star-shaped Co / CeO2@NC composite material prepared in Comparative Example 1 is shown in the figure. Figure 5 As shown, it is shown that the star structure is beneficial to improving the ORR performance.
[0092] Figure 6 The scanning electron microscope (SEM) image, high-resolution transmission electron microscope (TEM) image and high-angle annular dark-field transmission electron microscope image of the Co / CeO2@NC composite material prepared in Example 1 prove that each element is uniformly distributed in the composite material.
[0093] Figure 7 The LSV diagrams of ORR and OER of the Co / CeO2@NC composite material prepared in Example 1, the Co@NC prepared in Comparative Example 2, the CeO2@NC prepared in Comparative Example 3, and the NC prepared in Comparative Example 4 are shown. RuO2@NC is a precious metal material (its preparation method is: calcining ruthenium trichloride at 400°C in an air atmosphere for 2h to obtain RuO2@NC). It is used as a comparative sample for OER performance, indicating that the Co / CeO2@NC composite material has excellent bifunctional catalytic performance.
[0094] Figure 8 This is the stability diagram of ORR and OER of the Co / CeO2@NC composite material prepared in Example 1, which proves that the ORR stability of the Co / CeO2@NC composite material is better than that of the precious metal Pt / C, and also proves that the Co / CeO2@NC composite material has good OER stability.
[0095] Figure 9The open circuit voltage and maximum power density diagrams of the liquid zinc-air battery prepared using the Co / CeO2@NC composite material in Example 1 show that the open circuit voltage of the battery prepared with the Co / CeO2@NC composite material is higher than that of the battery prepared with the precious metal Pt / C, and the maximum power density of the battery prepared with the Co / CeO2@NC composite material is higher than that of Pt / C, which proves that the Co / CeO2@NC composite material is superior to Pt / C in the performance of liquid zinc-air batteries.
[0096] Figure 10 The liquid zinc-air battery prepared by using the Co / CeO2@NC composite material in Example 1 was tested at a current density of 5 mA·cm -2 The stability diagram of the device proves that it has good stability and good application prospects.
[0097] Figure 11 The open circuit voltage, maximum power density and the current density of the liquid zinc-air battery prepared by the Co / CeO2@NC composite material in Example 1 are shown in FIG. -2 The stability diagram of the Co / CeO2@NC composite material shows that the Co / CeO2@NC composite material has good discharge capacity and good cycle stability.
[0098] Figure 12 This is the SEM image of the non-star-shaped structure material prepared in Comparative Example 1. It can be seen that the Co / CeO2@NC composite material finally prepared in Comparative Example 1 is a non-star-shaped structure.
[0099] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.
Claims
1. A method for preparing a star-shaped Co / CeO2@NC composite material, characterized in that: The method comprises the following steps: adding a soluble zinc salt, a soluble cobalt salt, a soluble cerium salt, dimethylimidazole and hexadecyltrimethylammonium bromide into a solvent, reacting under stirring conditions, washing and drying the product after the reaction, and then calcining the product to obtain the star-shaped Co / CeO2@NC composite material.
2. The method for preparing the star-shaped Co / CeO2@NC composite material according to claim 1, characterized in that: The usage ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, dimethylimidazole and hexadecyltrimethylammonium bromide is 2mmol: (0.85-0.9)mmol: (0.1-0.2)mmol: 54.8mmol: 10mg.
3. The method for preparing the star-shaped Co / CeO2@NC composite material according to claim 2, characterized in that: The usage ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, dimethylimidazole and hexadecyltrimethylammonium bromide is 2mmol:0.8mmol:0.2mmol:54.8mmol:10mg.
4. The method for preparing the star-shaped Co / CeO2@NC composite material according to claim 2, characterized in that: The usage ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, dimethylimidazole and hexadecyltrimethylammonium bromide is 2mmol:0.85mmol:0.15mmol:54.8mmol:10mg.
5. The method for preparing the star-shaped Co / CeO2@NC composite material according to claim 2, characterized in that: The usage ratio of the soluble zinc salt, the soluble cobalt salt, the soluble cerium salt, dimethylimidazole and hexadecyltrimethylammonium bromide is 2mmol:0.9mmol:0.1mmol:54.8mmol:10mg.
6. The method for preparing the star-shaped Co / CeO2@NC composite material according to claim 1, characterized in that: The reaction was carried out under stirring at a temperature of 25±2° C. for 3 h.
7. The method for preparing the star-shaped Co / CeO2@NC composite material according to claim 1, characterized in that: The calcination temperature is 810-1100° C. and the time is 2 hours; the calcination is carried out in an inert gas atmosphere.
8. The method for preparing the star-shaped Co / CeO2@NC composite material according to claim 7, characterized in that: The calcination temperature is 910°C.
9. A star-shaped Co / CeO2@NC composite material, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 8.
10. Use of the star-shaped Co / CeO2@NC composite material according to claim 9 in a rechargeable zinc-air battery, characterized in that: The star-shaped Co / CeO2@NC composite material is used as a cathode catalyst.