A composite nano-array material, electrode, supercapacitor and preparation method thereof having Se vacancies

Abstract

The present invention belongs to the field of supercapacitors, and particularly relates to a composite nanoarray material with Se vacancies, an electrode, a supercapacitor and a preparation method thereof. The present invention directly prepares CuO nanorods on a copper foam (CF) substrate; uses CuO as a working electrode, Hg / HgO as a reference electrode, a platinum sheet as a counter electrode, and a mixed solution of Ni(NO3)2·6H2O, Co(NO3)2·6H2O and SeO2 as an electrolyte, and deposits NiCo-Se on the surface of CuO by cyclic voltammetry on an electrochemical workstation to synthesize a CuO@NiCo-Se nanoarray; immerses the CuO@NiCo-Se material in a KBH4 solution to generate Se vacancies, obtaining a high-performance V Se -CuO@NiCo-Se electrode material. Through the synergistic regulation of morphology and composition, the present invention significantly improves the specific capacitance and stability of the composite material, and has excellent energy storage performance and cycling performance, providing a superior composite electrode material for supercapacitors. Moreover, the raw materials of the preparation method are widely sourced, low in price, high in preparation efficiency, and have broad application prospects.

Description

Technical Field

[0001] The invention belongs to the field of supercapacitors, and in particular relates to a composite nano-array material with Se vacancies, an electrode, a supercapacitor and a preparation method thereof. Background Art

[0002] As environmental pollution and fossil fuel consumption become increasingly serious, people's demand for energy storage systems with high power and high energy density continues to increase. As a new type of portable energy storage device, supercapacitors have the advantages of long cycle life, high energy conversion efficiency, high power density, high safety factor, easy detection, and no environmental pollution during the production process, providing a new research direction for energy storage.

[0003] As the core part of supercapacitors, the performance of electrode materials will directly affect the performance and application areas of supercapacitors. Therefore, developing high-performance electrode materials is the most effective way to improve the electrochemical performance of supercapacitors and the most direct way to achieve commercial application of supercapacitors.

[0004] Among the numerous electrode materials, transition metal compounds represented by transition metal selenides have attracted much attention due to their pseudocapacitive energy storage mode that can provide a high theoretical capacity. As a binary metal compound, NiCo bimetallic compound has a high theoretical specific capacity due to the similar potential window of cobalt and nickel cations, which is conducive to providing a variety of redox reactions in the electrochemical process. In addition, existing studies have shown that although CoNiSe2 constructed on the surface of nickel foam through micro-nanostructure design as a composite nanoarray material with Se vacancies has a good specific capacity, it is easy to agglomerate during electrochemical testing, and the active sites are gradually reduced during the cycle. In addition, the agglomerated nanoparticles will shrink / expand in volume during the charge and discharge process, thereby reducing the electrochemical performance of the CoNiSe2 electrode material. Summary of the invention

[0005] In view of this, the present invention provides a CuO@NiCo-Se (V) with Se vacancies to solve the problems that the existing NiCo selenides have serious agglomeration, stacking, unstable structure and poor conductivity during the preparation process, which seriously limit their application in supercapacitors. Se -CuO@NiCo-Se) composite nanoarray electrode material.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The first technical purpose of the present invention is to provide a composite nano-array material with Se vacancies, wherein the electrode material is a CuO@NiCo-Se composite nano-array electrode material with Se vacancies, that is, V Se -CuO@NiCo-Se electrode material.

[0008] The second technical purpose of the present invention is to provide a method for preparing the composite nanoarray material having Se vacancies as described above, the method specifically comprising the following steps:

[0009] (1) Preparation of CuO nanorod arrays:

[0010] Firstly, the copper foam CF is pretreated, and then a NaOH solution and a (NH4)2S2O8 solution are prepared respectively, and then the (NH4)2S2O8 solution is slowly poured into the NaOH solution and continuously stirred to obtain a mixed solution; the pretreated copper foam CF is tiltedly immersed in the mixed solution at room temperature, and after immersion, the copper foam CF is washed with ethanol and deionized water and dried in a vacuum, and then the obtained Cu(OH)2 is annealed to obtain a CuO nanorod array;

[0011] (2) Preparation of CuO@NiCo-Se nanoarrays:

[0012] The CuO nanorod array prepared in step (1) was used as a working electrode, Hg / HgO was used as a reference electrode, a platinum sheet was used as a counter electrode, and a mixed solution of Ni(NO3)2·6H2O, Co(NO3)2·6H2O and SeO2 was used as an electrolyte. NiCo-Se was deposited on the CuO surface by cyclic voltammetry on an electrochemical workstation, and the mixture was washed with ethanol and deionized water and dried in a vacuum to obtain a CuO@NiCo-Se nanoarray.

[0013] (3) CuO@NiCo-Se nanoarrays with Se vacancies (V Se Preparation of NiCo-CuO@NiCo-Se:

[0014] The CuO@NiCo-Se nanoarray material prepared in step (2) was immersed in KBH4 solution to generate Se vacancies, washed with ethanol and deionized water, and vacuum dried to obtain V Se -CuO@NiCo-Se nanoarray, that is, the composite nanoarray material with Se vacancies.

[0015] Optionally, in step (1), the specific operation process of pre-processing CF is as follows:

[0016] The CF with a size of 1.0 cm × 3.0 cm was ultrasonically cleaned with acetone, 3 M hydrochloric acid, and ethanol for 10-20 min, respectively, and then rinsed with deionized water for 3-5 times. Finally, the CF was placed in a vacuum drying oven at 55-65°C to dry overnight.

[0017] Furthermore, in step (1), the molar ratio of the NaOH solution to the (NH4)2S2O8 solution is 20:1, the foam copper CF is immersed for 5-20 min, the vacuum drying temperature is 55-65°C, and it is dried overnight.

[0018] Furthermore, in step (1), the obtained Cu(OH)2 is placed in a muffle furnace at 2-5°C min -1 The CuO nanorod arrays were obtained by annealing at 300-350℃ for 2-3 h.

[0019] Optionally, in step (2), the electrolyte is a mixed solution of Ni(NO3)2·6H2O, Co(NO3)2·6H2O and SeO2 in an equimolar ratio, and the concentration of the mixed solution is 0.05-0.1 M.

[0020] Furthermore, in step (2), the voltage range of -1.2 to -0.2 V is 5-10 mV s -1 The scanning rate was 5-20 cycles to obtain the CuO@NiCo-Se nanoarray; the vacuum drying temperature was 55-65°C and dried overnight.

[0021] Optionally, in step (3), the concentration of the KBH4 solution is 0.05-0.2 M, the immersion time is 1-5 min, and the vacuum drying temperature is 55-65°C, and the drying is done overnight.

[0022] The third technical purpose of the present invention is to provide a supercapacitor electrode, wherein the electrode material in the supercapacitor electrode includes the composite nanoarray material having Se vacancies as described above.

[0023] The fourth technical purpose of the present invention is to provide a supercapacitor, which contains the composite nanoarray material with Se vacancies as described above; or contains the composite nanoarray material with Se vacancies prepared by the method as described above; or contains the supercapacitor electrode as described above.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. Cu(OH)2 nanorods were synthesized by impregnation on a porous conductive CF current collector, and then further annealed to synthesize a CuO nanorod array. The Cu(OH)2 nanorods were evenly and regularly distributed on the CF substrate. The CuO nanorods formed after annealing have almost the same morphology as Cu(OH)2, except that they are slightly curled. The nanorod structure is conducive to the rapid transmission of electrons and the diffusion of ions, thus improving the overall electrochemical performance of the electrode material. In addition, the design of the electrode structure without the addition of a binder can accelerate the charge transfer process between the substrate surface and the active material. The obtained CuO nanorod electrode material has a high conductivity at 3 A g -1 At a current density of 1.5 %, the specific capacity can reach 523 F g -1 .

[0026] 2. The present invention deposits CoNi-Se electrode material on CuO nanorods to solve the serious agglomeration and stacking of CoNi-Se powder materials in the preparation process. In addition, a layer of nanosheets is deposited on the smooth surface of the nanorods, and the surface becomes rough. This rough surface is conducive to exposing more active sites, thereby improving the electrochemical performance of the electrode material. The obtained CuO@NiCo-Se nanoarray electrode material has a high electrochemical performance at 3 A g -1 At a current density of 1.34 W, the specific capacity can reach 1477 Fg -1 , which is 3 times the specific capacity of CuO nanorod electrode. In addition, the CoNi-Se electrode material deposited directly on CF exhibited deposition agglomeration on its surface, and the CF@NiCo-Se at 3 A g -1 At a current density of 1.3 Å, the specific capacity is only 665 F g -1 .

[0027] 3. The vacancy generation process is accompanied by a series of physical and chemical changes, such as the breaking of old bonds and the formation of new bonds, lattice distortion, electron compensation, electron localization, and interstitial states at the Fermi level, so vacancies will affect the electronic structure of the material and the ion diffusion dynamics. In addition, vacancies act as electron donors or acceptors to promote the movement of electrons inside the material and improve the conductivity of the material. Vacancies also generate additional active charge storage sites, enhancing the charge storage capacity of electrode materials. Therefore, the introduction of Se vacancies can increase the conductivity and active charge storage sites of electrode materials, thereby improving electrochemical performance.

[0028] 4. The present invention prepares V by coordinated regulation of morphology and composition. Se -CuO@NiCo-Se electrode material showed excellent electrochemical performance and cycle stability at 3 A g -1 At a current density of 2.5 %, the specific capacity can reach 2890 F g -1 , even at 20 A g -1At high current density, it has 2741 F g -1 The specific capacity of the supercapacitor can be as high as 82% after 10,000 cycles, which is twice the specific capacity of the CuO@NiCo-Se electrode. The preparation method has a wide range of raw materials, low price, high preparation efficiency, and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0030] Figure 1 This is a SEM image of Cu(OH)2 prepared in Example 1 of the present invention.

[0031] Figure 2 is a SEM image of CuO prepared in Example 1 of the present invention.

[0032] Figure 3 It is a charge and discharge curve diagram of CuO prepared in Example 1 of the present invention.

[0033] Figure 4 This is a SEM image of Cu(OH)2 prepared in Example 2 of the present invention.

[0034] Figure 5 is a SEM image of CuO prepared in Example 2 of the present invention.

[0035] Figure 6 This is a SEM image of CuO@NiCo-Se prepared in Example 2 of the present invention.

[0036] Figure 7 It is a charge and discharge curve diagram of CuO@NiCo-Se prepared in Example 2 of the present invention.

[0037] Figure 8 This is a cycle stability test chart of CuO@NiCo-Se prepared in Example 2 of the present invention.

[0038] Fig. 9 It is a SEM image of CF@NiCo-Se prepared in Comparative Example 1 of the present invention.

[0039] Fig.10 It is a charge and discharge curve diagram of CF@NiCo-Se prepared in comparative example 1 of the present invention.

[0040] Fig.11It is a rate curve diagram of CF@NiCo-Se prepared in comparative example 1 of the present invention.

[0041] Fig.12 This is a SEM image of Cu(OH)2 prepared in Example 3 of the present invention.

[0042] Fig.13 This is a SEM image of CuO prepared in Example 3 of the present invention.

[0043] Fig.14 This is a SEM image of CuO@NiCo-Se prepared in Example 3 of the present invention.

[0044] Fig.15 V prepared in Example 3 of the present invention Se -SEM image of CuO@NiCo-Se.

[0045] Fig.16 V prepared in Example 3 of the present invention Se -Charge and discharge curves of CuO@NiCo-Se.

[0046] Fig.17 V prepared in Example 3 of the present invention Se -Rate curve of CuO@NiCo-Se.

[0047] Fig.18 V prepared in Example 3 of the present invention Se -CuO@NiCo-Se cycling stability test diagram.

[0048] Fig.19 This is a SEM image of Cu(OH)2 prepared in Example 4 of the present invention.

[0049] Fig. 20 is a SEM image of CuO prepared in Example 4 of the present invention.

[0050] Fig.21 This is a SEM image of CuO@NiCo-Se prepared in Example 4 of the present invention.

[0051] Fig. 22 V prepared in Example 4 of the present invention Se -SEM image of CuO@NiCo-Se.

[0052] Fig.23 V prepared in Example 4 of the present invention Se -Charge and discharge curves of CuO@NiCo-Se.

[0053] Fig.24 V prepared in Example 4 of the present invention Se -Rate curve of CuO@NiCo-Se.

[0054] Fig.25 V prepared in Example 4 of the present invention Se -CuO@NiCo-Se cycling stability test diagram.

[0055] Fig.26 This is a SEM image of Cu(OH)2 prepared in Example 5 of the present invention.

[0056] Fig. 27 is a SEM image of CuO prepared in Example 5 of the present invention.

[0057] Fig.28 This is a SEM image of CuO@NiCo-Se prepared in Example 5 of the present invention.

[0058] Fig.29 V prepared in Example 5 of the present invention Se -SEM image of CuO@NiCo-Se.

[0059] Fig.30 V prepared in Example 5 of the present invention Se -Charge and discharge curves of CuO@NiCo-Se.

[0060] Fig.31 V prepared in Example 5 of the present invention Se -Rate curve of CuO@NiCo-Se.

[0061] Fig.32 V prepared in Example 5 of the present invention Se -CuO@NiCo-Se cycling stability test diagram. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0064] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0065] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0066] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present application.

[0067] The present invention discloses a method for preparing a high-performance composite nano-array material with Se vacancies, which mainly comprises the following steps:

[0068] (1) Preparation of CuO nanorod arrays:

[0069] In order to remove the oxide layer on the CF substrate, the CF substrate was first pretreated. The CF with a size of 1.0 cm×3.0 cm was ultrasonically cleaned with acetone, 3 M hydrochloric acid, and ethanol for 10-20 min, respectively, and then rinsed with deionized water for 3-5 times, and then placed in a vacuum drying oven at 55-65°C to dry overnight; then NaOH solution and (NH4)2S2O8 solution were prepared with a molar ratio of 20:1, and the mixture was stirred for 10-20 min. The CF was tilted and stood in a beaker containing the mixed solution for 5-20 min. After soaking, the CF was washed with ethanol and deionized water for 3-5 times, and dried in a vacuum drying oven at 55-65°C overnight to obtain Cu(OH)2. The entire experimental process was carried out at room temperature; finally, Cu(OH)2 was placed in a muffle furnace at 2-5°C min -1 The CuO nanorod arrays were obtained by annealing at 300-350℃ for 2-3 h.

[0070] (2) Preparation of CuO@NiCo-Se nanoarrays:

[0071] The CuO nanorod array prepared in step (1) was used as the working electrode, Hg / HgO as the reference electrode, platinum sheet as the counter electrode, and the electrolyte was a mixed solution of Ni(NO3)2·6H2O, Co(NO3)2·6H2O and SeO2 in an equimolar ratio. The concentration of the mixed solution was 0.05-0.1 M. Cyclic voltammetry was performed on an electrochemical workstation in the voltage range of -1.2 to -0.2 V at a speed of 5-10 mVs -1 The scanning rate was cycled for 5-20 times, and the electrode material after electrochemical deposition was washed with ethanol and deionized water for 3-5 times and dried in a vacuum drying oven at 55-65°C overnight to obtain CuO@NiCo-Se nanoarrays.

[0072] (3) CuO@NiCo-Se nanoarrays with Se vacancies (V Se Preparation of NiCo-CuO@NiCo-Se:

[0073] CuO@NiCo-Se was immersed in a KBH4 solution with a concentration of 0.05-0.2 M for 1-5 min to generate Se vacancies, then washed with ethanol and deionized water for 3-5 times and dried in a vacuum oven at 55-65 °C overnight to obtain V Se -CuO@NiCo-Se nanoarrays.

[0074] In order to better understand the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as a limitation of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the protection scope of the present invention.

[0075] Embodiment 1:

[0076] CF with a size of 1.0 cm×3.0 cm was ultrasonically cleaned with acetone, 3 M hydrochloric acid, and ethanol for 10 min respectively, and then placed in a vacuum drying oven at 60°C for overnight after being rinsed with deionized water three times; 10 mL of 2.5 M NaOH solution and 10 mL of 0.125 M (NH4)2S2O8 solution were prepared respectively, and the (NH4)2S2O8 solution was slowly poured into the NaOH solution and stirred continuously for 10 min to make the two solutions mix more evenly; the pretreated CF was then tilted and stood in a beaker containing the mixed solution for 10 min, and then washed with ethanol and deionized water three times, and dried in a vacuum drying oven at 60°C for overnight to obtain Cu(OH)2; finally, Cu(OH)2 was placed in a muffle furnace at 2°C min -1 The CuO nanorod arrays were obtained by annealing at 350 °C for 2 h at a heating rate of .

[0077] The SEM images of the prepared Cu(OH)2 and CuO are shown in Figure 1-2 As shown in the figure, the CuO nanorod electrode material obtained is 3 A g -1 At a current density of 1.34 W, the specific capacity is only 523 F g -1 ( Figure 3 ).

[0078] Embodiment 2:

[0079] CF with a size of 1.0 cm×3.0 cm was ultrasonically cleaned with acetone, 3 M hydrochloric acid, and ethanol for 10 min respectively, and then placed in a vacuum drying oven at 65°C for overnight after being rinsed with deionized water for 5 times; 20 mL of 2.5 M NaOH solution and 20 mL of 0.125 M (NH4)2S2O8 solution were prepared respectively, and the (NH4)2S2O8 solution was slowly poured into the NaOH solution and stirred for 15 min to make the two solutions mix more evenly; the pretreated CF was then tilted and stood in a beaker containing the mixed solution for 15 min, and then washed with ethanol and deionized water for 5 times, and dried in a vacuum drying oven at 65°C for overnight to obtain Cu(OH)2; finally, Cu(OH)2 was placed in a muffle furnace at 1°C min -1 The CuO nanorod arrays were obtained by annealing at 300 °C for 2.5 h at a heating rate of .

[0080] The CuO electrode was used as the working electrode, Hg / HgO as the reference electrode, and the platinum sheet as the counter electrode. 0.05 mmol Ni(NO3)2·6H2O, 0.05 mmol Co(NO3)2·6H2O, and 0.05 mmol SeO2 were added to 40 mL of deionized water and mixed evenly as the electrolyte. Cyclic voltammetry was performed on an electrochemical workstation in the voltage range of -1.2 to -0.2 V at 5 mVs -1 The scanning rate was cycled for 15 times, and the electrode material after electrochemical deposition was washed with ethanol and deionized water for 5 times and dried in a vacuum drying oven at 65 °C overnight to obtain CuO@NiCo-Se nanoarrays.

[0081] The SEM images of the prepared Cu(OH)2, CuO, and CuO@NiCo-Se are shown in Figure 4-6 As shown in the figure, the obtained CuO@NiCo-Se electrode material has a -1 At a current density of 1.34 W, the specific capacity is increased to 1477 F g -1 ( Figure 7 ), and the cycle stability is 84% ​​( Figure 8 ).

[0082] Embodiment 3:

[0083] The CF with a size of 1.0 cm×3.0 cm was ultrasonically cleaned with acetone, 3 M hydrochloric acid, and ethanol for 10 min, respectively. After being rinsed with deionized water three times, the CF was placed in a vacuum drying oven at 60°C overnight. 10 mL of 2.5 M NaOH solution and 10 mL of 0.125 M (NH4)2S2O8 solution were prepared respectively. The (NH4)2S2O8 solution was slowly poured into the NaOH solution and stirred continuously for 10 min to make the two solutions mix more evenly. The pretreated CF was then tilted and stood in a beaker containing the mixed solution for 10 min, then washed with ethanol and deionized water three times, and dried in a vacuum drying oven at 60°C overnight to obtain Cu(OH)2; finally, the Cu(OH)2 was placed in a muffle furnace at 2°C min -1 The CuO nanorod arrays were obtained by annealing at 350℃ for 2 h at a heating rate of 1.5 ℃. The CuO electrode was used as the working electrode, Hg / HgO as the reference electrode, and the platinum sheet as the counter electrode. 0.075 mmol Ni(NO3)2·6H2O, 0.075 mmol Co(NO3)2·6H2O, and 0.075 mmol SeO2 were added to 40 mL of deionized water and mixed evenly as the electrolyte. Cyclic voltammetry was performed on an electrochemical workstation in the voltage range of -1.2 to -0.2 V at 5 mVs -1 The scanning rate was cycled for 10 cycles. The electrode material after electrochemical deposition was washed with ethanol and deionized water for 3 times and dried in a vacuum oven at 60°C overnight to obtain CuO@NiCo-Se nanoarrays. CuO@NiCo-Se was immersed in a 0.1 M KBH4 solution for 2 min to generate Se vacancies, then washed with ethanol and deionized water for 3 times and dried in a vacuum oven at 60°C overnight to obtain V Se -CuO@NiCo-Se nanoarrays.

[0084] The prepared Cu(OH)2, CuO, CuO@NiCo-Se and V Se -SEM image of CuO@NiCo-Se Figure 12-15 As shown. Se -CuO@NiCo-Se electrode at 3 A g -1 At a current density of 2.5 %, the specific capacity is as high as 2890 F g -1 ( Fig.16 ), even at 20 Ag -1 At high current density, it has 2741 F g -1 The specific capacity ( Fig.17 ), and without sacrificing the cycle stability of the electrode material, the capacity retention rate can reach 83.12% after 10,000 charge and discharge cycles ( Fig.18 ).

[0085] Embodiment 4:

[0086] The CF with a size of 1.0 cm×3.0 cm was ultrasonically cleaned with acetone, 3 M hydrochloric acid, and ethanol for 10 min respectively. After being rinsed with deionized water for 5 times, the CF was placed in a vacuum drying oven at 65°C and dried overnight. 20 mL of 2.5 M NaOH solution and 20 mL of 0.125 M (NH4)2S2O8 solution were prepared respectively. The (NH4)2S2O8 solution was slowly poured into the NaOH solution and stirred for 15 min to make the two solutions mix more evenly. The pretreated CF was then tilted and stood in a beaker containing the mixed solution for 15 min, then washed with ethanol and deionized water for 5 times, and dried in a vacuum drying oven at 65°C overnight to obtain Cu(OH) 2； Finally, Cu(OH)2 was placed in a muffle furnace at 1°C min -1 The CuO nanorod arrays were obtained by annealing at 300℃ for 2.5 h at a heating rate of 1.5 ℃. The CuO electrode was used as the working electrode, Hg / HgO as the reference electrode, and the platinum sheet as the counter electrode. 0.05 mmol Ni(NO3)2·6H2O, 0.05 mmol Co(NO3)2·6H2O, and 0.05 mmol SeO2 were added to 40 mL of deionized water and mixed evenly as the electrolyte. Cyclic voltammetry was performed on an electrochemical workstation in the voltage range of -1.2 to -0.2 V at 5 mVs -1 The scanning rate was cycled for 15 cycles. The electrode material after electrochemical deposition was washed with ethanol and deionized water for 5 times and dried in a vacuum oven at 65 °C overnight to obtain CuO@NiCo-Se nanoarrays. CuO@NiCo-Se was immersed in a KBH4 solution with a concentration of 0.05 M for 5 min to generate Se vacancies, then washed with ethanol and deionized water for 5 times and dried in a vacuum oven at 65 °C overnight to obtain V Se -CuO@NiCo-Se nanoarrays.

[0087] The prepared Cu(OH)2, CuO, CuO@NiCo-Se and V Se -SEM image of CuO@NiCo-Se Figure 19-22 As shown. Se -CuO@NiCo-Se electrode at 3 A g -1 At a current density of 2.5 %, the specific capacity is as high as 2880 F g -1 ( Fig.23 ), even at 20 Ag -1 At high current density, it has 2632 F g -1 The specific capacity ( Fig.24), and without sacrificing the cycle stability of the electrode material, the capacity retention rate can reach 82% after 10,000 charge and discharge cycles ( Fig.25 ).

[0088] Embodiment 5:

[0089] The CF with a size of 1.0 cm×3.0 cm was ultrasonically cleaned with acetone, 3 M hydrochloric acid, and ethanol for 10 min, respectively. After being rinsed with deionized water for 5 times, the CF was placed in a vacuum drying oven at 55°C overnight. 10 mL of 2.5 M NaOH solution and 10 mL of 0.125 M (NH4)2S2O8 solution were prepared respectively. The (NH4)2S2O8 solution was slowly poured into the NaOH solution and stirred for 10 min to make the two solutions mix more evenly. The pretreated CF was then tilted and stood in a beaker containing the mixed solution for 10 min, then washed with ethanol and deionized water 4 times, and dried in a vacuum drying oven at 55°C overnight to obtain Cu(OH) 2； Finally, Cu(OH)2 was placed in a muffle furnace at 3℃ min -1 The CuO nanorod arrays were obtained by annealing at 350℃ for 3 h at a heating rate of 1.5 %. The CuO electrode was used as the working electrode, Hg / HgO as the reference electrode, and the platinum sheet as the counter electrode. 0.1 mmol Ni(NO3)2·6H2O, 0.1 mmol Co(NO3)2·6H2O, and 0.1 mmol SeO2 were added to 40 mL of deionized water and mixed evenly as the electrolyte. Cyclic voltammetry was performed on an electrochemical workstation in the voltage range of -1.2 to -0.2 V at 10 mV s -1 The scanning rate was cycled for 20 cycles. The electrode material after electrochemical deposition was washed with ethanol and deionized water 4 times and dried in a vacuum oven at 55°C overnight to obtain CuO@NiCo-Se nanoarrays. CuO@NiCo-Se was immersed in a 0.1 M KBH4 solution for 1 min to generate Se vacancies, then washed with ethanol and deionized water 4 times and dried in a vacuum oven at 55°C overnight to obtain V Se -CuO@NiCo-Se nanoarrays.

[0090] The prepared Cu(OH)2, CuO, CuO@NiCo-Se and V Se -SEM image of CuO@NiCo-Se Figure 26-29 As shown. Se -CuO@NiCo-Se electrode at 3 A g -1 At a current density of 2.5 %, the specific capacity is as high as 2878 F g -1 ( Fig.30 ), even at 20 Ag -1At high current density, it has 2628 F g -1 The specific capacity ( Fig.31 ), and without sacrificing the cycle stability of the electrode material, the capacity retention rate can reach 80.08% after 10,000 charge and discharge cycles ( Fig.32 ).

[0091] In order to further demonstrate the beneficial effects of the present invention and to better understand the present invention, the following comparative examples are used to further illustrate the technical features disclosed in the present invention, but they should not be construed as limiting the present invention. Other improvements made by those skilled in the art based on the above invention content without inventive work are also considered to fall within the scope of protection of the present invention.

[0092] Comparative Example 1:

[0093] CF with a size of 1.0 cm×3.0 cm was ultrasonically cleaned with acetone, 3 M hydrochloric acid, and ethanol for 10 min, respectively. After being rinsed with deionized water three times, CF was placed in a vacuum drying oven at 60°C overnight. CF was used as the working electrode, Hg / HgO as the reference electrode, and platinum as the counter electrode. 0.075 mmol Ni(NO3)2·6H2O, 0.075 mmol Co(NO3)2·6H2O, and 0.075 mmol SeO2 were added to 40 mL of deionized water and mixed evenly as the electrolyte. Cyclic voltammetry was performed on an electrochemical workstation in the voltage range of -1.2 to -0.2 V at 5 mV s -1 The scanning rate was cycled for 10 cycles. The electrode material after electrochemical deposition was washed with ethanol and deionized water for 3 times and dried in a vacuum oven at 60 °C overnight to obtain CF@NiCo-Se nanoarrays. The SEM image is shown in Fig. 9 As shown in the figure, the obtained CuO@NiCo-Se electrode material has a -1 At a current density of 1.3 Å, the specific capacity is only 665 F g -1 ( Fig.10 ), when the current density increases to 20 A g -1 When the F g -1 The specific capacity ( Fig.11 ).

[0094] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a composite nanoarray material having Se vacancies, characterized in that: The method specifically comprises the following steps: (1) Preparation of CuO nanorod arrays: Firstly, the copper foam CF is pretreated, and then a NaOH solution and a (NH4)2S2O8 solution are prepared respectively, and then the (NH4)2S2O8 solution is slowly poured into the NaOH solution and continuously stirred to obtain a mixed solution; the pretreated copper foam CF is tiltedly immersed in the mixed solution at room temperature, and after immersion, the copper foam CF is washed with ethanol and deionized water and dried in a vacuum, and then the obtained Cu(OH)2 is annealed to obtain a CuO nanorod array; (2) Preparation of CuO@NiCo-Se nanoarrays: The CuO nanorod array prepared in step (1) is used as a working electrode, Hg / HgO is used as a reference electrode, a platinum sheet is used as a counter electrode, and a mixed solution of Ni(NO3)2·6H2O, Co(NO3)2·6H2O and SeO2 is used as an electrolyte. NiCo-Se is deposited on the CuO surface by cyclic voltammetry on an electrochemical workstation, and the mixture is washed with ethanol and deionized water and dried in a vacuum to obtain a CuO@NiCo-Se nanoarray. (3) CuO@NiCo-Se nanoarrays with Se vacancies (V Se Preparation of NiCo-CuO@NiCo-Se: The CuO@NiCo-Se nanoarray material prepared in step (2) was immersed in KBH4 solution to generate Se vacancies, washed with ethanol and deionized water, and vacuum dried to obtain V Se -CuO@NiCo-Se nanoarray, i.e., the composite nanoarray material with Se vacancies; In step (1), the obtained Cu(OH)2 is placed in a muffle furnace at 2-5°C min -1 The CuO nanorod arrays were obtained by annealing at 300-350℃ for 2-3h at a heating rate of .

2. The method for preparing a composite nanoarray material having Se vacancies according to claim 1, characterized in that: In step (1), the specific operation process of pre-processing CF is as follows: A CF with a size of 1.0 cm×3.0 cm was ultrasonically cleaned with acetone, 3M hydrochloric acid, and ethanol for 10-20 min, respectively, and then rinsed with deionized water for 3-5 times. Finally, the CF was placed in a vacuum drying oven at 55-65° C. to dry overnight.

3. The method for preparing a composite nanoarray material having Se vacancies according to claim 1 or 2, characterized in that: In step (1), the molar ratio of NaOH solution to (NH4)2S2O8 solution is 20:1, the foam copper CF is immersed for 5-20 minutes, the vacuum drying temperature is 55-65°C, and the foam is dried overnight.

4. The method for preparing a composite nanoarray material having Se vacancies according to claim 1, characterized in that: In step (2), the electrolyte is a mixed solution of Ni(NO3)2·6H2O, Co(NO3)2·6H2O and SeO2 in an equimolar ratio, and the concentration of the mixed solution is 0.05-0.1M.

5. The method for preparing a composite nanoarray material having Se vacancies according to claim 1 or 4, characterized in that: In step (2), the voltage range is -1.2 to -0.2 V at 5-10 mVs -1 The scanning rate was 5-20 cycles to obtain the CuO@NiCo-Se nanoarray; the vacuum drying temperature was 55-65°C and dried overnight.

6. The method for preparing a composite nanoarray material having Se vacancies according to claim 1, characterized in that: In step (3), the concentration of KBH4 solution is 0.05-0.2M, the soaking time is 1-5min, the vacuum drying temperature is 55-65°C, and the drying is done overnight.

7. A supercapacitor electrode, characterized in that: The electrode material in the supercapacitor electrode includes a composite nanoarray material having Se vacancies prepared by the method according to any one of claims 1 to 6.

8. A supercapacitor, characterized in that: A composite nanoarray material having Se vacancies prepared by the method according to any one of claims 1 to 6; Or, the supercapacitor electrode as claimed in claim 7.

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