NiO / C / Cu2O-coated CF self-supporting composite electrode material and preparation method thereof
By anchoring NiO/C on the Cu2O nanotube array, forming a porous structure and forming a three-dimensional conductive network, the cycle life and conductivity problems of the transition metal oxide supercapacitor positive electrode material are solved, and electrode materials with high specific capacitance and long life are achieved.
Patent Information
- Application Number
- CN202510682606.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-26
- Publication Date
- 2025-08-08
AI Technical Summary
When conventional transition metal oxides are used as the positive electrode material of supercapacitors, their cycle life is poor, their conductivity is poor, and their structure is unstable during charging and discharging.
Using NiO/C/Cu2O@CF self-supporting composite electrode material, NiO/C is anchored on the Cu2O nanotube array to form a porous structure, improve ion diffusion and electron transport capabilities, and a three-dimensional conductive network is formed through Ni-MOF high-temperature calcination to inhibit NiO/C agglomeration and volume expansion.
It significantly improves the specific capacitance and cyclic stability of the self-supported composite electrode material, extends the cycle life of the electrode, and improves the conductivity and structural stability.
Smart Images
Figure CN120453073A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of supercapacitor positive electrode materials, and in particular to a NiO / C / Cu2O@CF self-supporting composite electrode material and a preparation method thereof. Background Art
[0002] Transition metal oxides (TMOs) have attracted significant attention in the energy storage field due to their high theoretical specific capacity, abundant resources, and low cost. They primarily store energy through redox reactions at the electrode-electrolyte interface. Currently reported single metal oxides commonly used as cathode materials for supercapacitors (SCs) include NiO, Co₃O₄, and Cu₂O.
[0003] When nickel oxide (NiO) and cuprous oxide (Cu2O) are used as electrode materials for SCs, they react with hydroxide in the alkaline electrolyte to transform into electrochemically active hydroxides or oxyhydroxides, thereby generating pseudocapacitance. However, single TMOs still have some shortcomings as positive electrode materials for supercapacitors. First, their poor conductivity hinders charge transfer and limits the performance of the capacitor. Second, the charge and discharge process may cause volume expansion, resulting in unstable electrode structure and affecting the cycle life and performance of the capacitor. Summary of the Invention
[0004] A problem with existing technologies is that conventional transition metal oxides used as positive electrode active materials in SCs result in poor cycle life for the resulting supercapacitors. To address this technical issue, the present invention provides a NiO / C / Cu2O@CF self-supporting composite electrode material, which comprises the following preparation steps:
[0005] (1) Copper hydroxide is loaded on the surface of the current collector to obtain a Cu(OH)2@CF precursor;
[0006] (2) calcining the Cu(OH)2@CF precursor at high temperature under nitrogen or inert atmosphere to obtain CuO@CF electrode material;
[0007] (3) Ni-MOF is loaded on the surface of the CuO@CF electrode material to obtain a Ni-MOF / Cu2O@CF composite electrode material;
[0008] (4) The Ni-MOF / Cu2O@CF composite electrode is placed in nitrogen or an inert atmosphere for high-temperature calcination to obtain a NiO / C / Cu2O@CF self-supporting composite electrode material.
[0009] Preferably, the method of step (1) comprises the following steps:
[0010] The NaOH aqueous solution and the (NH4)2S2O8 aqueous solution were mixed evenly, and the pretreated CF was placed in the mixed solution and allowed to react at room temperature. After the reaction was completed, the obtained solution was washed and dried in sequence to obtain the Cu(OH)2@CF precursor.
[0011] Preferably, the pretreatment method of CF comprises the following steps:
[0012] The CF was cut into the required size, and then placed in anhydrous acetone and dilute hydrochloric acid for ultrasonic pretreatment for at least 20 minutes, with an ultrasonic frequency of at least 30 kHz. After being taken out, it was washed with deionized water and anhydrous ethanol for multiple times, and then vacuum dried to obtain the pretreated CF.
[0013] Preferably, the high temperature calcination temperature in step (2) is 100-300°C.
[0014] Preferably, the high-temperature calcination time in step (2) is 1-3 hours.
[0015] Preferably, step (3) comprises the following steps:
[0016] Nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and terephthalic acid (PTA) are dissolved in N,N dimethylformamide (DMF) solvent to form a uniform mixed solution, and then the CuO@CF electrode material is placed in the mixed solution, and then transferred to a high-pressure reactor for high-temperature hydrothermal reaction. After the reaction is completed, the obtained solution is washed with deionized water and ethanol for multiple times, and then vacuum dried to obtain Ni-MOF / Cu2O@CF composite electrode material. Step (3) CuO@CF is composited with Ni-MOF by hydrothermal method, DMF is decomposed at high temperature to generate reducing dimethylamine and formic acid, and CuO (Cu 2+ ) is reduced to Cu2O(Cu + ).
[0017] Preferably, the temperature of the high-temperature hydrothermal reaction is 100-140°C.
[0018] Preferably, the high temperature hydrothermal reaction time is 6-14 hours.
[0019] Preferably, the high-temperature calcination temperature in step (4) is 350°C.
[0020] Preferably, the high-temperature calcination time in step (4) is 1-2 hours.
[0021] The present invention has the following beneficial effects:
[0022] (1) The NiO / C / Cu2O@CF self-supporting composite electrode material obtained in the present invention is supported by a Cu2O nanotube array, which stably anchors the flower-shaped NiO / C on the Cu2O surface, thereby effectively inhibiting the agglomeration of NiO / C and improving the ion diffusion and electron transport capabilities within the self-supporting composite electrode material;
[0023] (2) The porous NiO / C structure formed after high-temperature calcination of Ni-MOF significantly improves the conductivity and structural stability of Cu2O nanotubes. The two work together to significantly improve the specific capacitance and cycle stability of the NiO / C / Cu2O@CF self-supporting composite electrode material.
[0024] (3) After high-temperature calcination, the Ni-MOF precursor forms a three-dimensional conductive network carbon layer structure on the NiO surface, which further improves the conductivity of NiO and effectively inhibits the volume expansion of NiO during the charge and discharge process, effectively improving the cycle life of the obtained NiO / C / Cu2O@CF self-supporting composite electrode material. The NiO / C composite electrode retains the characteristics of large specific surface area and high porosity of the Ni-MOF material, providing more redox active sites for the composite electrode, which is very beneficial to further improve the electrochemical performance of the obtained NiO / C / Cu2O@CF self-supporting composite electrode material. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 These are SEM images of (a) CuO@CF electrode material, (b) Ni-MOF / Cu2O@CF electrode material, and (c) NiO / C / Cu2O@CF self-supporting composite electrode material prepared in Example 1.
[0026] Figure 2 These are the XRD patterns of the CuO@CF electrode material, Ni-MOF / Cu2O@CF electrode material, and NiO / C / Cu2O@CF self-supporting composite electrode material obtained in Example 1.
[0027] Figure 3 This is a CV curve test diagram of the NiO / C / Cu2O@CF self-supporting composite electrode material obtained in Example 1 at different scanning speeds.
[0028] Figure 4 This is the GCD curve of the NiO / C / Cu2O@CF self-supporting composite electrode material obtained in Example 1 at different current densities.
[0029] Figure 5 The self-supporting composite electrode materials obtained in Examples 1-3 were respectively -2 GCD comparison curve when .
[0030] Figure 6 The composite electrode materials obtained in Example 1 and Comparative Examples 1-2 were respectively -2 GCD comparison curve when .
[0031] Figure 7 The NiO / C / Cu2O@CF self-supporting composite electrode material obtained in Example 1 was tested at 10 mA cm -2 Capacity retention test chart after 2000 cycles of charge and discharge at a current density of .
[0032] Figure 8 The self-supporting composite electrode materials obtained in Example 1 and Comparative Examples 3-4 are respectively -2 Capacity retention test chart after 2000 cycles of charge and discharge at a current density of .
[0033] Figure 9 The self-supporting composite electrode materials obtained in Example 1 and Comparative Examples 3-4 were respectively -2 GCD curve at current density. DETAILED DESCRIPTION
[0034] The present invention will be described in detail below with reference to the following examples. However, it should be understood that the following examples are merely illustrative of the embodiments of the present invention and are not intended to limit the scope of the present invention.
[0035] The current collector CF (foam copper) used in the following examples and comparative examples of the present invention was purchased from Tianjin Avixin Chemical Technology Co., Ltd. and has a size of 15 cm×15 cm×0.1 cm.
[0036] Example 1
[0037] A NiO / C / Cu2O@CF self-supporting composite electrode material, the preparation method is as follows:
[0038] (1) Cut the CF into 1×3.5cm 2 The CF was then placed in anhydrous acetone and 3 mol / L hydrochloric acid for ultrasonic pretreatment for 20 min at an ultrasonic frequency of 30 kHz. After being taken out, it was washed with deionized water and anhydrous ethanol for 3 times, and dried in a vacuum drying oven at 60 ° C for 12 h to obtain the pretreated CF.
[0039] (2) 1 g NaOH and 0.285 g (NH4)2S2O8 were dissolved in 10 mL deionized water respectively. After mixing the two solutions, they were stirred to form a uniform transparent solution. The pretreated CF was placed in the above solution and allowed to react at room temperature for 20 minutes. After the reaction was completed, the CF was collected and washed with deionized water three times, then placed in a vacuum drying oven and dried at 50 °C for 12 h to obtain the Cu(OH)2@CF precursor.
[0040] (3) Place Cu(OH)2@CF in a tube furnace, heat it to 200°C at a rate of 2°C / min under a nitrogen atmosphere, and keep it at that temperature for 2 h. After cooling naturally to room temperature, the CuO@CF electrode material is obtained.
[0041] (4) 0.24 g Ni(NO3)2·6H2O and 0.048 g PTA were dissolved in 20 mL DMF solvent to form a mixed solution, which was magnetically stirred for 30 min and then thoroughly mixed. The CuO@CF electrode material obtained in step (2) was then placed in the mixed solution and then transferred to a 50 mL high-pressure reactor for hydrothermal reaction at 120°C for 12 h. After the reaction was completed, the reaction product was washed three times with deionized water and ethanol in sequence, and vacuum dried at 60°C for 12 h to obtain a Ni-MOF / Cu2O@CF composite electrode material.
[0042] (5) The Ni-MOF / Cu2O@CF composite electrode material was placed in a tubular furnace, heated to 350°C at a rate of 5°C / min under a nitrogen atmosphere and kept warm for 1 h. After the insulation was completed, it was naturally cooled to room temperature to obtain the NiO / C / Cu2O@CF self-supporting composite electrode material.
[0043] Example 2 is the same as Example 1, except that the calcination temperature in step (5) of Example 2 is 300°C.
[0044] Example 3 is the same as Example 1, except that the calcination temperature in step (5) of Example 3 is 600°C.
[0045] Comparative Example 1 is the same as Example 1, except that there is no step (5) in Comparative Example 1, and the electrode material obtained in Comparative Example 1 is a Ni-MOF / Cu2O@CF composite electrode material.
[0046] Comparative Example 2 is the same as Example 1, except that step (4) in Comparative Example 2 is carried out according to the following steps:
[0047] 0.825 g Ni(NO3)2·6H2O, 0.14 g NH4F and 0.675 g CO(NH2)2 were added to 30 mL deionized water, magnetically stirred for 30 min, and then fully mixed. Then, the CuO@CF electrode material obtained in step (3) was added, and then transferred to a 50 mL high-pressure reactor and hydrothermally reacted at 120°C for 12 h. After the reaction, CF was washed three times with deionized water and vacuum dried at 50°C for 12 h to obtain a Ni(OH)2 / CuO@CF composite electrode material. After being treated with the same step (5) as in Example 1, a NiO / CuO@CF electrode composite material was obtained.
[0048] Comparative Example 3 is the same as Example 1, except that the amount of Ni(NO3)2·6H2O used in step (4) is 0.16 g and the amount of PTA used is 0.032 g.
[0049] Comparative Example 4 is the same as Example 1, except that the amount of Ni(NO3)2·6H2O used in step (4) is 0.36 g and the amount of PTA used is 0.072 g.
[0050] Performance Testing
[0051] GCD, CV, and EIS tests were performed using a Swiss Metrohm electrochemical workstation (PGSTAT-302N). The electrodes obtained in the Examples and Comparative Examples were used as working electrodes in a three-electrode system, with a platinum mesh as the counter electrode, a Hg / HgO electrode as the reference electrode, and a 2 mol / L KOH aqueous solution as the electrolyte. The CV curves of the Examples and Comparative Examples were tested in the operating voltage range of 0-0.6 V and at scan rates of 5 mv, 10 mv, 20 mv, 30 mv, and 50 mv·s. -1 , the current density for testing GCD curve is 5mA, 10mA, 20mA, 30mA, 50mA cm -2 The embodiment of the present invention and the comparative example are -2 The specific results of the measured specific capacitance are shown in Table 1 and Table 1.
[0052] Table 1
[0053] Test items <![CDATA[Specific capacitance (5 mA cm -2 )]]> Example 1 <![CDATA[7.13F cm -2 ]]> Example 2 <![CDATA[3.99F cm -2 ]]> Example 3 <![CDATA[6.15F cm -2 ]]>
[0054] Table 1
[0055]
[0056]
[0057] The SEM images of (a) CuO@CF electrode material, (b) Ni-MOF / Cu2O@CF electrode material, and (c) NiO / C / Cu2O@CF self-supporting electrode composite material prepared in Example 1 are shown in the attached manual. Figure 1 shown.
[0058] Figure 1 Figures (a) and (b) show that the CuO nanoneedles are densely and evenly distributed on the substrate. During the synthesis of Ni-MOF, DMF will partially decompose into dimethylamine ((CH3)2NH) and formic acid (HCOOH) with strong reducing properties at high temperatures. These substances act as reducing agents to reduce CuO (Cu 2+ ) was successfully transformed into Cu2O(Cu + ) nanotubes, whose size is significantly increased compared with the precursor ( Figure 1 (c), (d)). In addition, the Ni-MOF flowers are anchored on the surface of Cu2O nanotubes without agglomeration. After carbonization of the composite structure, the obtained NiO / C / Cu2O heterostructure still maintains good flower-like morphology. Due to the presence of the surface carbon layer and a large number of pores, the average diameter of NiO / C increases ( Figure 1 (e), (f)). The self-supporting composite electrode material undergoes overall volume expansion while maintaining close bonding between the components, resulting in good adhesion between NiO / C and Cu2O.
[0059] Figure 2 The XRD patterns of CuO@CF electrode material, Ni-MOF / Cu2O@CF electrode material and NiO / C / Cu2O@CF self-supporting electrode composite material obtained in Example 1 are shown in FIG. Figure 2 It can be seen that the characteristic peaks of Cu2O match the crystal planes of the standard card (PDF#05-0667). The diffraction peaks appearing in the Ni-MOF / Cu2O electrode material are composed of Cu2O and Ni-MOF phases, which is consistent with the SEM image results. After high-temperature annealing, the diffraction peaks of Ni-MOF disappear. The diffraction peaks observed at 37.2° and 62.8° represent the (111) and (220) crystal planes of NiO, respectively (JCPDS 47-1049). The carbon has no obvious crystalline phase peaks, indicating that it is amorphous carbon. The peak position of Cu2O does not disappear in the final sample, confirming the successful composite of NiO / C / Cu2O.
[0060] Figure 3 The CV curves of the NiO / C / Cu2O@CF self-supporting electrode composite obtained in Example 1 at different scan rates are shown. The results show that as the scan rate increases, the redox peak intensity gradually increases, and the shape remains stable, indicating that the sample has good capacitive performance. Figure 4The GCD curves of NiO / C / Cu2O@CF self-supporting electrode composites at different current densities are nearly symmetrical. -2 The specific capacitance is 7.13 F cm -2 .
[0061] Figure 5 Examples 1-3 are shown to be -2 Constant current charge and discharge (GCD) curve under current density. The test results show that the sample of Example 1 exhibits the longest discharge time, the best specific capacity characteristics and good coulombic efficiency. Further comparative analysis Figure 6 From the GCD curves of Example 1 and Comparative Examples 1-2 under the same test conditions, it can be seen that the NiO / C composite material derived from Ni-MOF (Example 1) shows more significant advantages in specific capacitance performance than the NiO material derived from Ni(OH)2 (Comparative Example 2), confirming the important influence of the precursor structure on the electrochemical properties of the electrode material.
[0062] Figure 7 This is a cycling performance diagram of the NiO / C / Cu2O@CF self-supporting electrode composite material obtained in Example 1 as the working electrode in a three-electrode system. It can be seen from the figure that after 2000 charge and discharge cycles, the NiO / C / Cu2O@CF self-supporting electrode composite material can still maintain 95.73% of its initial capacitance, and can still maintain excellent capacity values after long-term cycling. Therefore, it can be promoted and used as an electrode material in supercapacitors.
[0063] Figure 8 The cycling performance comparison results of the electrode materials obtained in Example 1 and Comparative Examples 3-4 are shown. -2 At a current density of , after 2000 constant current charge and discharge cycle tests, the NiO / C / Cu2O@CF self-supporting electrode composite material obtained in Example 1 exhibited excellent capacity retention, with a capacity retention rate of 95.73%, which was higher than that of Comparative Example 3 (91.34%) and Comparative Example 4 (86.1%).
[0064] Figure 9 The electrode materials obtained in Example 1 and Comparative Examples 3-4 were -2 The GCD curve at the current density of 1000 nm is shown in FIG1 , wherein the specific capacitance of the NiO / C / Cu2O@CF self-supporting electrode composite material obtained in Example 1 reaches 7.13 F cm -2 The specific capacitances of the electrode materials obtained in Comparative Examples 3 and 4 were 6.33 F cm -2 and 4.05F cm -2 , proving that Example 1 has the best energy storage performance.
[0065] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.
Claims
1. A NiO / C / Cu2O@CF self-supporting composite electrode material, characterized in that: The method comprises the following preparation steps: (1) Copper hydroxide is loaded on the surface of the current collector CF to obtain a Cu(OH)2@CF precursor; (2) calcining the Cu(OH)2@CF precursor at high temperature under nitrogen or inert atmosphere to obtain CuO@CF electrode material; (3) Ni-MOF is loaded on the surface of the CuO@CF electrode material to obtain a Ni-MOF / Cu2O@CF composite electrode material; (4) The Ni-MOF / Cu2O@CF composite electrode is placed in nitrogen or an inert atmosphere for high-temperature calcination to obtain a NiO / C / Cu2O@CF self-supporting composite electrode material.
2. The NiO / C / Cu2O@CF self-supporting composite electrode material according to claim 1, characterized in that: The preparation method of step (1) comprises the following steps: The NaOH aqueous solution and the (NH4)2S2O8 aqueous solution were mixed evenly, and the pretreated CF was placed in the mixed solution and allowed to react at room temperature. After the reaction was completed, the obtained solution was washed and dried in sequence to obtain the Cu(OH)2@CF precursor.
3. The NiO / C / Cu2O@CF self-supporting composite electrode material according to claim 2, characterized in that: The pretreatment method of CF includes the following steps: The CF was cut into the required size, and then placed in anhydrous acetone and dilute hydrochloric acid for ultrasonic pretreatment for at least 20 minutes, with an ultrasonic frequency of at least 30 kHz. After being taken out, it was washed with deionized water and anhydrous ethanol for multiple times, and then vacuum dried to obtain the pretreated CF.
4. The NiO / C / Cu2O@CF self-supporting composite electrode material according to claim 1, characterized in that: The high temperature calcination temperature in step (2) is 100-300°C.
5. The NiO / C / Cu2O@CF self-supporting composite electrode material according to claim 1, characterized in that: The high temperature calcination time in step (2) is 1-3 hours.
6. The NiO / C / Cu2O@CF self-supporting composite electrode material according to claim 1, characterized in that: The preparation method of step (3) comprises the following steps: Ni(NO3)2·6H2O and PTA were dissolved in DMF solvent to form a uniform mixed solution. The CuO@CF electrode material was then placed in the mixed solution and transferred to a high-pressure reactor for high-temperature hydrothermal reaction. After the reaction, the obtained solution was washed with deionized water and ethanol in sequence, and then vacuum-dried to obtain the Ni-MOF / Cu2O@CF composite electrode material.
7. The NiO / C / Cu2O@CF self-supporting composite electrode material according to claim 6, characterized in that: The temperature of the high-temperature hydrothermal reaction is 100-140°C.
8. The NiO / C / Cu2O@CF self-supporting composite electrode material according to claim 6, characterized in that: The high-temperature hydrothermal reaction time is 6-14h.
9. The NiO / C / Cu2O@CF self-supporting composite electrode material according to claim 1, characterized in that: The high temperature calcination temperature in step (4) is 350°C.
10. The NiO / C / Cu2O@CF self-supporting composite electrode material according to claim 1, characterized in that: The high-temperature calcination time in step (4) is 1-2 hours.