Preparation method and application of (NixCo1-x) 0.85 Se / N-MoSe2 heterojunction
By preparing (NixCo1-x) 0.85Se/N-MoSe2 heterojunction, the problems of low specific capacity and poor cycle stability in supercapacitors are solved, and supercapacitor electrodes with high energy density and excellent cycle stability are achieved, which are suitable for large-scale Production.
Patent Information
- Application Number
- CN202411400992.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-09
- Publication Date
- 2025-01-10
AI Technical Summary
The specific capacity of metal selenide in existing supercapacitors is low, the cycle stability is not ideal, and there is a lot of room for improvement in performance.
A method of preparation of (NixCo1-x) 0.85Se/N-MoSe2 heterojunction is adopted. By dispersing N-MoSe2 ultrasonic, the nickel-cobalt ions are uniformly attached, and the hydrothermal reaction is carried out in combination with selenium powder to prepare high specific capacity and excellent cycles. Stable heterojunction powder and applied to supercapacitor electrodes.
It significantly improves the specific capacity and cycle stability of supercapacitors, is suitable for high energy density applications, is simple in preparation process and low in cost, and is suitable for large-scale production.
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Figure CN119296986A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of preparation of energy storage materials and energy storage performance evaluation, and specifically to a (Ni x Co 1-x ) 0.85 Preparation method and application of Se / N-MoSe2 heterojunction. Background Art
[0002] As a competitive energy storage device, supercapacitors have been widely studied due to their high power density, fast charge and discharge rates, and low maintenance costs. The energy storage capacity of supercapacitors depends largely on the electrode materials in the device. Generally speaking, compared with double-layer and pseudocapacitor materials, battery-like materials can provide greater specific capacity and energy density. Therefore, people have been committed to developing battery-like electrode materials with excellent performance. Among various battery-like electrode materials, transition metal selenides have attracted much attention due to their high conductivity, excellent electrochemical activity, diverse valence states, and abundant content in nature. Among transition metal selenides, nickel selenide (such as NiSe, NiSe2, Ni 0.85 Se, etc.) and cobalt selenide (such as CoSe, CoSe2, Co 0.85 Se, etc.) are favored by researchers due to their diverse valence states, abundant raw materials, good conductivity, and high theoretical capacity. Compared with single metal selenides, the introduction of the second metal element makes bimetallic selenides have higher electrochemical activity. Various morphologies of Ni-Co bimetallic selenides have been tried in the field of supercapacitors, such as: Ni 0.67 Co 0.33 Se nanoparticles and hollow spheres, hollow sea urchin-like Ni 0.5 Co 0.5 Se2, Ni-Co-Se nanowires and polyhedrons, hollow NiSe-CoSe nanoparticles, NiCoSe2 polyhedrons and hollow spheres, coral-like Ni 0.9 Co 1.92 Se4, hollow (Ni, Co) Se2, (Ni x Co 1-x )9Se8 nanodendrites, CoNiSe2 nanorods, core / shell structure (NiCo)9Se8 / (NiCo) 0.85 Se and NiCo2Se4 nanosheets. In Ni-Co bimetallic selenides, the coexistence of Ni and Co can not only provide abundant redox active sites, but also exert the synergistic effect of the bimetallic, thereby improving the electrochemical performance of metal selenides. Metal selenides and molybdenum diselenide have attracted great attention as supercapacitor electrode materials, but their specific capacities are relatively low, and their cycle stability is not ideal, and there is still much room for improvement in performance. Summary of the invention
[0003] The object of the present invention is to provide a (Ni x Co 1-x ) 0.85 The preparation method and application of Se / N-MoSe2 heterojunction are used to solve the problems existing in the prior art mentioned in the above background technology.
[0004] To achieve the above object, the present invention provides the following technical solutions:
[0005] A (Ni x Co 1-x ) 0.85 The preparation method of Se / N-MoSe2 heterojunction comprises the following steps:
[0006] S1: ultrasonically disperse a certain amount of N-MoSe2 in water to form a uniform N-MoSe2 dispersion A;
[0007] S2: dissolving nickel nitrate and cobalt nitrate in different mass ratios in N-MoSe2 dispersion, and ultrasonically homogenizing the mixture so that nickel and cobalt ions are uniformly attached to the surface of N-MoSe2 to form precursor B;
[0008] S3: dissolving a certain amount of selenium powder in the reducing agent solution and stirring to form a uniform selenized solution C;
[0009] S4: Add the selenized liquid C into the precursor B and stir evenly to obtain a hydrothermal precursor D;
[0010] S5: Transfer the precursor D to a hydrothermal reactor, perform hydrothermal reaction under certain conditions, and then centrifuge, wash, and dry to obtain (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction powder.
[0011] Preferably, the mass ratio of N-MoSe2 in S1 to the volume ratio of water is 5 mg / 1 mL.
[0012] Preferably, the molar ratio of nickel nitrate to cobalt nitrate in S2 is 1:4-4:1.
[0013] Preferably, the reducing agent in S3 is one of hydrazine hydrate or sodium borohydride.
[0014] Preferably, the hydrothermal reaction conditions in S5 are: keeping warm at 120° C. for 12 hours, and the detergents are ethanol and water.
[0015] The present invention also provides a (Ni x Co 1-x ) 0.85 Application of Se / N-MoSe2 heterojunctionx Co 1-x ) 0.85 Se / N-MoSe2 heterojunction powder is used in supercapacitors.
[0016] Preferably, the application includes the preparation and performance evaluation of electrodes for supercapacitors, and the specific method is as follows:
[0017] (1) Electrode preparation: x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction, conductive agent and binder are mixed and ground in NMP in a certain proportion, and then the slurry is evenly coated on the current collector, vacuum dried, and pressed into a thin sheet electrode;
[0018] (2) Electrochemical activity evaluation: (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction electrode was used as working electrode, Hg / HgO electrode as reference electrode and Pt sheet electrode as counter electrode to construct a three-electrode system, and the electrochemical activity of the electrodes was studied by CV and GCD techniques.
[0019] (3) Assembly and energy storage performance evaluation of hybrid capacitors: (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction electrode was used as the positive electrode, activated carbon electrode as the negative electrode, and KOH solution as the electrolyte to assemble a hybrid supercapacitor. The energy storage performance of the capacitor was studied using CV, GCD and EIS techniques.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] 1. The (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction is better than N-MoSe2 or single metal selenide / N-MoSe2 heterojunction (Ni 0.85 Se / N-MoSe2 or Co 0.85 The specific capacity of Se / N-MoSe2) is improved, and it can be applied to supercapacitors with high energy density.
[0022] 2. The (Ni 0.8 Co 0.2 ) 0.85 The hybrid capacitor assembled with Se / N-MoSe2 heterojunction exhibits excellent cycling stability.
[0023] 3. The preparation process of the present invention is simple, easy to operate, has low requirements on preparation conditions, does not require complex equipment, is low in cost, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 For Examples 1-5 and Comparative Examples 1-2 prepared (Ni x Co 1-x ) 0.85 XRD pattern of Se / N-MoSe2 heterojunction.
[0025] Figure 2 For Examples 1-5 and Comparative Examples 1-2 prepared (Ni x Co 1-x ) 0.85 CV curves of Se / N-MoSe2 heterojunction at a scan rate of 20 mV / s.
[0026] Figure 3 For Examples 1-5 and Comparative Examples 1-2 prepared (Ni x Co 1-x ) 0.85 GCD curve of Se / N-MoSe2 heterojunction electrode at a current density of 0.5 A / g.
[0027] Figure 4 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85 CV plots of Se / N-MoSe2 / / AC hybrid capacitor at different scan rates.
[0028] Figure 5 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85 GCD curves of Se / N-MoSe2 / / AC hybrid capacitors at current densities of 0.5–10 A / g.
[0029] Figure 6 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85Lagung plot of Se / N-MoSe2 / / AC hybrid capacitor.
[0030] Figure 7 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85 Cycling performance diagram of Se / N-MoSe2 / / AC hybrid capacitor.
[0031] Figure 8 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85 Phase angle versus frequency plot for Se / N-MoSe2 / / AC hybrid capacitor. DETAILED DESCRIPTION
[0032] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.
[0033] See also Figure 1-8 , the present invention provides the following technical solutions:
[0034] Example 1
[0035] A (Ni x Co 1-x ) 0.85 The preparation method of Se / N-MoSe2 heterojunction comprises the following steps:
[0036] S1: Weigh 100.0 mg N-MoSe2, add 20.0 mL ultrapure water, and disperse evenly by ultrasonic to obtain dispersion A;
[0037] S2: 0.8mmol Ni(NO3)2·6H2O and 0.2mmol Co(NO3)2·6H2O were dissolved in dispersion A and homogenized by ultrasonication to obtain precursor B;
[0038] S3: Weigh 2.0 mmol of Se powder and dissolve it in 10.0 mL of N2H4·H2O. Stir for 30 min and mark it as selenization solution C.
[0039] S4: Slowly add the selenide solution C to the precursor B and continue stirring for 30 minutes to obtain the hydrothermal precursor D;
[0040] S5: The hydrothermal precursor D was transferred to a 50.0 mL lined autoclave, placed in an oven, and kept at 120 ° C for 12 h. After the temperature cooled, the precipitate in the liner was transferred to a centrifuge tube, washed with ultrapure water and ethanol for 3 times each, and then transferred to a vacuum drying oven and kept at 60 ° C for 6 h to obtain (Ni 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 sample.
[0041] The steps of Example 2-5 and Comparative Example 1-2 are the same as those of Example 1, but the ingredients are different, as shown in the following table:
[0042]
[0043] Evaluation of electrochemical activity and energy storage performance
[0044] The (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction was made into a test electrode. First, the three-electrode method was used to test (Ni x Co 1-x ) 0.85 The electrochemical activity of Se / N-MoSe2 heterojunction electrode. Then activated carbon was used as the negative electrode, (Ni 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunction as the positive electrode, assembled (Ni 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 / / AC hybrid capacitor, using CV, GCD and EIS to study the energy storage performance of the capacitor. The specific steps are as follows:
[0045] (1) Electrode preparation: First, weigh (Ni) in a weight percentage of 80%:10%:10% x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction, acetylene black and PVDF are added with an appropriate amount of NMP to prepare a slurry, and then the slurry is coated on nickel foam, placed in a vacuum drying oven, dried at 80°C for 12h, and pressed into thin sheets as working electrodes after drying.
[0046] (2) Electrochemical activity evaluation: (Ni x Co 1-x ) 0.85 A three-electrode system was constructed using Se / N-MoSe2 heterojunction as the working electrode, Hg / HgO electrode as the reference electrode, and Pt sheet electrode as the counter electrode. The electrochemical activity of the electrodes was studied using CV and GCD techniques.
[0047] (3) Assembly and energy storage performance evaluation of hybrid capacitors: (Ni 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunction is the positive electrode, AC electrode is the negative electrode, and the assembly (Ni 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 / / AC hybrid capacitor, the energy storage performance of the capacitor was studied using CV, GCD and EIS techniques.
[0048] Figure 1 The (Ni x Co 1-x ) 0.85 XRD pattern of Se / N-MoSe2 heterojunction. As can be seen from the figure, Figure 1 The diffraction peaks at 33.3°, 44.7°, 50.6°, 60.4°, 61.9°, 69.9° and 71.3° are consistent with Ni 0.85 Se(JCPDS No.18-0888) and Co 0.85 Se (JCPDS No.52-1008), indicating that (Ni x Co 1-x ) 0.85 Se. In addition, from Figure 1 It can also be seen that with the increase of Ni content, the diffraction peak gradually increases, indicating that (Ni x Co 1-x ) 0.85 The crystallinity of Se / N-MoSe2 heterojunction gradually improves with the increase of Ni content.
[0049] Figure 2 For Examples 1-5 and Comparative Examples 1-2 prepared (Ni x Co 1-x ) 0.85 CV curve of Se / N-MoSe2 heterojunction at a scan rate of 20mV / s. Figure 2 It can be seen that there are obvious oxidation / reduction peaks on all curves, indicating that the electrode mainly relies on redox reactions to store energy. x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction is a battery-type electrode material. 0.8 Co 0.2 ) 0.85 The area enclosed by the CV curve of Se / N-MoSe2 electrode is the largest, indicating that it has the greatest electrochemical activity.
[0050] Figure 3 For Examples 1-5 and Comparative Examples 1-2 prepared (Ni x Co 1-x ) 0.85 GCD curve of Se / N-MoSe2 heterojunction electrode at 0.5A / g current density. Figure 3 It can be seen that (Ni 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 electrode has the longest discharge time, therefore, (Ni 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 electrode has the highest specific capacity. -1 At a current density of (Ni 0.8 Co 0.2 ) 0.85 The specific capacity of Se / N-MoSe2 composite electrode is 397.9C / g, which is greater than that of Ni 0.85 Se / N-MoSe2 and Co 0.85 Se / N-MoSe2 composite electrode and other Ni / Co ratio conditions (Ni x Co 1-x ) 0.85 / N-MoSe2 electrode, this result further confirms that (Ni x Co 1-x ) 0.85 Synergistic enhancement effect between Ni and Co in Se / N-MoSe2 composite.
[0051] Figure 4 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85 CV curve of Se / N-MoSe2 / / AC asymmetric supercapacitor at 2-100mV / s. 0.8 Co 0.2 ) 0.85 The maximum operating voltage of Se / N-MoSe2 / / AC hybrid capacitor can be extended to 1.6 V. -1 At the scanning rate, each CV curve has a pair of oxidation / reduction peaks, indicating that (Ni 0.8 Co 0.2 ) 0.85Se / N-MoSe2 / / AC capacitors rely not only on double layers but also on Faraday reactions to store charge. As the scan rate increases, the area enclosed by the CV curve continues to increase, but the shape of the CV curve remains basically unchanged, which means that (Ni 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 / / AC capacitors have high rate performance and good reversibility.
[0052] Figure 5 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85 GCD curves of Se / N-MoSe2 / / AC hybrid capacitors at current densities of 0.5-10A / g. There is an inconspicuous voltage platform on the discharge curve, indicating that the asymmetric capacitor has a Faradaic reaction. At current densities of 0.5, 1, 2, 4, 6, 8, and 10A / g, the specific capacitances of the capacitors are 72.6, 66.9, 61.4, 56.0, 53.1, 50.3, and 47.9F / g, respectively.
[0053] Figure 6 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85 Lagung diagram of Se / N-MoSe2 / / AC hybrid capacitor. At a specific power of 400W / kg, (Ni 0.8 Co 0.2 ) 0.85 The Se / N-MoSe2 / / AC capacitor can provide a specific energy of 25.8Wh / kg. When the power density is increased to 8000W / kg, the capacitor can still provide a maximum specific energy of 17.0Wh kg.
[0054] Figure 7 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85 Cyclic performance of Se / N-MoSe2 / / AC hybrid capacitor. At 3A / g current density, (Ni 0.8 Co 0.2 )0.85 After 40,000 cycles, the capacity retention rate of the Se / N-MoSe2 / / AC capacitor is 92.9%, indicating that the capacitor has excellent cycle stability.
[0055] Figure 8 The (Ni prepared in Example 1 0.8 Co 0.2 ) 0.85 Se / N-MoSe2 heterojunctions assembled with (Ni 0.8 Co 0.2 ) 0.85 Phase angle and frequency relationship diagram of Se / N-MoSe2 / / AC hybrid capacitor. The relaxation time τ0 is 0.2s, indicating that (Ni 0.8 Co 0.2 ) 0.85 The response time of Se / N-MoSe2 electrode is very short, which can realize fast charge and discharge, further proving that (Ni 0.8 Co 0.2 ) 0.85 Fast electrochemical response of Se / N-MoSe2 / / AC capacitor.
[0056] The present invention prepares a bimetallic selenide / molybdenum diselenide heterojunction with a reasonable structure and applies it to supercapacitors, which has the following advantages: (1) N-MoSe2 with a large interlayer spacing is conducive to the diffusion of electrolyte ions and can provide more abundant active sites, which can accelerate the Faraday redox kinetics; (2) coupling (Ni x Co 1-x ) 0.85 Se can prevent the stacking of layered MoSe2 and form a good heterostructure, thereby maximizing the number of active sites in the heterostructure and enhancing the diffusion of electrolyte ions; (3) Construction (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction can not only play the role of (Ni x Co 1-x ) 0.85 The synergistic effect between Se and N-MoSe2 can also bring into play the synergistic effect between Ni and Co, thereby enhancing the kinetics of the Faraday redox reaction and thus improving the electrochemical performance.
[0057] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A (Ni x Co 1-x ) 0.85 The method for preparing a Se / N-MoSe2 heterojunction is characterized in that: The steps include: S1: ultrasonically disperse a certain amount of N-MoSe2 in water to form a uniform N-MoSe2 dispersion A; S2: dissolving nickel nitrate and cobalt nitrate in different mass ratios in N-MoSe2 dispersion, and ultrasonically homogenizing the mixture so that nickel and cobalt ions are uniformly attached to the surface of N-MoSe2 to form precursor B; S3: dissolving a certain amount of selenium powder in the reducing agent solution and stirring to form a uniform selenized solution C; S4: Add the selenized liquid C into the precursor B and stir evenly to obtain a hydrothermal precursor D; S5: Transfer the precursor D to a hydrothermal reactor, perform hydrothermal reaction under certain conditions, and then centrifuge, wash, and dry to obtain (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction powder.
2. A (Ni according to claim 1) x Co 1-x ) 0.85 The method for preparing a Se / N-MoSe2 heterojunction is characterized by: The mass ratio of N-MoSe2 in S1 to the volume ratio of water is 5 mg / 1 mL.
3. A (Ni according to claim 1 x Co 1-x ) 0.85 The method for preparing a Se / N-MoSe2 heterojunction is characterized by: The molar ratio of nickel nitrate to cobalt nitrate in S2 is 1:4-4:
1.
4. A (Ni according to claim 1 x Co 1-x ) 0.85 The method for preparing a Se / N-MoSe2 heterojunction is characterized by: The reducing agent in S3 is one of hydrazine hydrate and sodium borohydride.
5. A (Ni according to claim 1 x Co 1-x ) 0.85 The method for preparing a Se / N-MoSe2 heterojunction is characterized in that: The hydrothermal reaction conditions in S5 are: keeping warm at 120° C. for 12 hours, and the detergents are ethanol and water.
6. A method of preparing (Ni) by the method according to any one of claims 1 to 5 x Co 1-x ) 0.85 The application of Se / N-MoSe2 heterojunction is characterized by: (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction powder is used in supercapacitors.
7. A (Ni according to claim 6 x Co 1-x ) 0.85 The application of Se / N-MoSe2 heterojunction is characterized by: Including supercapacitor electrode preparation and performance evaluation, the specific methods are as follows: (1) Electrode preparation: x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction, conductive agent and binder are mixed and ground in NMP in a certain proportion, and then the colloid is evenly coated on the current collector, vacuum dried, and pressed into a thin sheet electrode; (2) Electrochemical activity evaluation: (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction electrode was used as working electrode, Hg / HgO electrode as reference electrode and Pt sheet electrode as counter electrode to construct a three-electrode system, and the electrochemical activity of the electrodes was studied by CV and GCD techniques. (3) Assembly and energy storage performance evaluation of hybrid capacitors: (Ni x Co 1-x ) 0.85 Se / N-MoSe2 heterojunction The junction electrode is the positive electrode, the activated carbon electrode is the negative electrode, and the KOH solution is the electrolyte to assemble the hybrid supercapacitor. The energy storage performance of capacitors was studied using CV, GCD and EIS techniques.