CN112700969B - A kind of sheet CeO2/Co1.29Ni1.71O4 electrode material and preparation method thereof - Google Patents

Abstract

The invention discloses a flaky CeO₂/Co_1.29Ni_1.71O₄An electrode material and a preparation method thereof, belonging to the technical field of electrode materials. The method comprises the following specific steps: ultrasonically cleaning and drying the foamed nickel to obtain clean foamed nickel; adding sodium dodecyl sulfate, urea, nickel nitrate and cobalt nitrate into water for dissolving, then dropwise adding a cerous nitrate aqueous solution to form a uniform solution, then adding foamed nickel for hydrothermal reaction, washing the reacted foamed nickel with water, washing with ethanol, drying, and oxidizing to obtain flaky CeO₂/Co_1.29Ni_1.71O₄An electrode material. The method is simple, the price of reactants is low, the preparation process is convenient, and the energy consumption is low. CeO prepared by the invention₂/Co_1.29Ni_1.71O₄The surface of the electrode material has a folded sheet structure, the specific surface area is large, the electrochemical performance is excellent, and the electrode material is suitable for the electrode material of the super capacitor.

Description

A kind of sheet CeO2/Co1.29Ni1.71O4 electrode material and preparation method thereof

technical field

The invention belongs to the technical field of electrode materials, and particularly relates to a sheet-shaped CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material and a preparation method thereof. The material is used as an electrode material of a super capacitor.

Background technique

With the progress of energy transformation, the demand for renewable intermittent energy supporting equipment is growing, so the society is eager to find an efficient and environmentally friendly energy storage device. As a new type of energy storage device, supercapacitors have the advantages of long cycle life, instantaneous power retention and high-power pulse applications. They have wide application scenarios and can be used in various industrial equipment. Therefore, it is necessary to prepare electrode materials with high specific capacitance to Improve supercapacitor performance.

Transition metal oxides are widely used as excellent electrode materials due to their high specific capacitance, good reversibility, many oxidation states in redox reactions, and higher electrochemical activity. However, most metal compounds have poor electrical conductivity and cycle stability, which affects the performance of supercapacitors.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention discloses a sheet-shaped CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material as a supercapacitor material and a preparation method thereof. The preparation method has a simple process, and the CeO ₂ /Co _1.29 Ni _1.71 O ₄ material grown on the nickel foam is obtained through a one-step hydrothermal method and oxidation. The reactant is cheap and green, the surfactant is biodegradable and environmentally friendly, and the obtained CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material has a higher specific capacitance.

The technical scheme of the present invention is:

A sheet-like CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material, a wrinkled sheet-like structure grows longitudinally _on the surface of a three-dimensional network of nickel foam, the sheet-like structure is thin and the spacing distribution is uniform. The electrical conductivity at the interface between the electrolyte and the active material improves the electrochemical performance of the electrode; the direct growth of the electrode material on the basis of nickel foam significantly enhances the electrical conductivity and stability of the material.

A preparation method of sheet-like CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material, comprising the following steps:

(1) Cleaning of nickel foam

The nickel foam was placed in hydrochloric acid for ultrasonic cleaning, then the nickel foam was placed in deionized water to continue ultrasonic cleaning, and finally the nickel foam was placed in anhydrous ethanol for ultrasonic cleaning, and vacuum dried at 50°C to 60°C to obtain clean nickel foam.

The pore size of the nickel foam is 110ppi, and the length×width×height is 30mm×10mm×1.5mm.

The ultrasonic cleaning time is 10-15 min.

The concentration of the hydrochloric acid is 1-2M.

(2) Stir to obtain a homogeneous solution

Add sodium dodecyl sulfate, urea, nickel nitrate hexahydrate and cobalt nitrate hexahydrate into deionized water, and stir to dissolve; add 10 mL of cerium nitrate aqueous solution under stirring, and continue stirring for 60-90 minutes to obtain a uniform solution.

The added amount of the sodium lauryl sulfate is 0.05-0.055g, the mass ratio of cobalt nitrate hexahydrate and nickel nitrate hexahydrate is 1:1, the added amount of urea is 0.045-0.055g, and the concentration of the cerium nitrate aqueous solution is 1.84 ~3.68 mmol/L.

(3) Hydrothermal reaction of nickel foam and homogeneous solution to obtain the first step product

The nickel foam obtained in step (1) and the homogeneous solution obtained in step (2) are poured into the reaction kettle, and the hydrothermal reaction is carried out under the condition of 170°C to 180°C, and the first step product is obtained after 10 to 13 hours.

The reaction temperature of the hydrothermal reaction is preferably 170°C, and the reaction time is preferably 12h.

(4) Wash the first-step product obtained in step (3) with water and ethanol, and then oxidize it in a muffle furnace at 300° C. to 400° C. for 2 to 4 hours to obtain a flaky CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode Material.

The beneficial effects of the present invention are as follows: 1) In the material preparation process, the hydrothermal method is adopted, the preparation process is simple to operate, and the requirements for synthesis conditions are low. 2) The raw materials are cheap and environmentally friendly, and appropriate amount of cerium doping can improve the performance of the electrode. 3) Nickel foam as a substrate effectively alleviates the defects of poor conductivity and poor cycle stability of traditional metal oxide electrode materials.

Description of drawings

FIG. 1 is a scanning electron microscope image of the flake CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material prepared by the present invention.

Fig. 2(a)-Fig. 2(d) are the Mapping element distribution diagrams of the sheet-like CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material prepared by the present invention; wherein, Fig. 2(a) shows three kinds of Ni, Co and Ce. Element distribution diagram, Figure 2(b) is the Ce element distribution diagram, Figure 2(c) is the Co element distribution diagram, and Figure 2(d) is the Ni element distribution diagram.

Fig. 3(a)-Fig. 3(d) are the XPS images of the sheet CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material prepared by the present invention; wherein, Fig. 3(a) is the full spectrum, Fig. 3(b) is the O1s spectrum, Figure 3(c) is the Ce3d and Ni2p spectrum, and Figure 3(d) is the Co2p spectrum.

FIG. 4 is a galvanostatic charge-discharge diagram of the sheet-like CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material prepared by the present invention at a current density of 1Ag ^-1 .

Detailed ways

The present invention will be further described below with reference to the embodiments and accompanying drawings.

Example 1

Cut out 30mm × 10mm × 1.5mm nickel foam with a pore size of 110ppi, soak it in 2M HCL for ultrasonic cleaning for 15 minutes, then ultrasonicate in deionized water for 10 minutes, and finally ultrasonicate in absolute ethanol for 10 minutes. The ultrasonicated nickel foam was vacuum-dried at 60 °C for 12 hours.

Weigh 0.050g of sodium dodecyl sulfate, 0.050g of urea, 0.116g of nickel nitrate hexahydrate and 0.116g of cobalt nitrate hexahydrate, dissolved in 20mL of deionized water, and stirred for 20min to obtain the initial solution; weigh 0.012g of cerium nitrate hexahydrate solution. In 10 mL of deionized water, an aqueous solution of cerium nitrate with a concentration of 2.76 mmol/L was obtained; the aqueous solution of cerium nitrate was slowly added dropwise to the initial solution under stirring, and a homogeneous solution was obtained by continuing to stir for 1 h.

The dried nickel foam and the homogeneous solution were moved into the reactor, reacted at 170 °C for 12 hours, the reacted nickel foam was washed with water, washed with ethanol, dried and oxidized in a muffle furnace at 300 °C for 2 hours to obtain flaky CeO ₂ / Co _1.29 Ni _1.71 O ₄ electrode material.

Fig. 1 is a scanning electron microscope image of the prepared CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material. It can be seen from the figure that the CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material is in sheet shape.

Fig. 2(a)-Fig. 2(d) are the Mapping element distribution diagrams of the prepared flaky CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material. The element distribution can be seen from Fig. 2(a)-(d) Very even.

Fig. 3(a)-Fig. 3(d) are the XPS images of the prepared CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material, Fig. 3(a) shows that the electrode material contains Ce, Co, Ni, O elements, Fig. 3( b) The Ce 3d spectrum shows that Ce ³⁺ and Ce ⁴⁺ are contained, it is obvious that Ce ³⁺ and Ce ⁴⁺ exist in CeO ₂ , and the presence of Ce ³⁺ indicates the presence of oxygen vacancies, thereby increasing the conductivity and promoting the redox reaction. The peaks at 855.7 eV and 873.4 eV in the Ni 2p spectrum of Fig. 3(c) correspond to Ni ³⁺ . Figure 3(d) The peaks at 780.3 eV and 795.6 eV in the Co 2p spectrum correspond to Co ²⁺ . Figure 3(b) O1s spectrum at 531.4 eV indicates a defect site with low oxygen coordination, and 529.5 eV indicates a typical metal-oxygen bond.

Figure 4 is the galvanostatic charge-discharge diagram of the prepared CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material under 1Ag ^-1 , which can be calculated from the discharge time and the specific capacitance calculation formula C _sp =It/SΔV for the electrode material under 1Ag ^-1 The specific capacitance is 1488Fg ^-1 , and the galvanostatic charge-discharge curves show good symmetry, indicating an excellent reversible redox reaction.

Example 2

Cut out 30mm × 10mm × 1.5mm nickel foam with a pore size of 110ppi, soak it in 1M HCL for ultrasonic cleaning for 10 minutes, then ultrasonicate in deionized water for 10 minutes, and finally ultrasonicate in absolute ethanol for 10 minutes. The ultrasonicated nickel foam was vacuum-dried at 60 °C for 12 hours.

Weigh 0.055 g of sodium dodecyl sulfate, 0.050 g of urea, 0.185 g of nickel nitrate hexahydrate and 0.185 g of cobalt nitrate hexahydrate and dissolve them in 20 mL of deionized water, and stir for 20 min to obtain an initial solution; In 10 mL of deionized water, a cerium nitrate aqueous solution with a concentration of 1.84 mmol/L was obtained; the cerium nitrate aqueous solution was slowly added dropwise to the initial solution under stirring, and a homogeneous solution was obtained by continuing to stir for 1 h.

The dried nickel foam and the homogeneous solution were transferred to the reactor at 170°C for 11h reaction, the reacted nickel foam was washed with water, washed with ethanol, dried and oxidized at 300°C for 3h to obtain a flaky CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode Material.

Example 3

Cut out 30mm × 10mm × 1.5mm nickel foam with a pore size of 110ppi, soak it in 2M HCL for ultrasonic cleaning for 15 minutes, then ultrasonicate in deionized water for 10 minutes, and finally ultrasonicate in absolute ethanol for 10 minutes. The ultrasonicated nickel foam was vacuum-dried at 60 °C for 12 hours.

Weigh 0.050 g of sodium dodecyl sulfate, 0.055 g of urea, 0.245 g of nickel nitrate hexahydrate and 0.245 g of cobalt nitrate hexahydrate into 20 mL of deionized water, and stir for 20 min to obtain an initial solution; In 10 mL of deionized water, an aqueous solution of cerium nitrate with a concentration of 3.68 mmol/L was obtained; the aqueous solution of cerium nitrate was slowly added dropwise to the initial solution under stirring, and the stirring was continued for 1.5 h to obtain a homogeneous solution, and the dried nickel foam and the homogeneous solution were transferred into the reaction The reaction was carried out at 180°C for 12h in the kettle, and the reacted nickel foam was washed with water, washed with ethanol, dried and oxidized at 300°C for 4h to obtain a sheet-like CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode material.

Example 4

Cut out 30mm×10mm×1.5mm nickel foam with a pore size of 110ppi, soak it in 2M HCL for ultrasonic cleaning for 15 minutes, then ultrasonicate in deionized water for 15 minutes, and finally ultrasonicate in absolute ethanol for 15 minutes. The ultrasonicated nickel foam was vacuum-dried at 60°C for 12 hours.

Weigh 0.050g of sodium dodecyl sulfate, 0.045g of urea, 0.3g of nickel nitrate hexahydrate and 0.3g of cobalt nitrate hexahydrate and dissolved in 20mL of deionized water, and stirred for 20min to obtain an initial solution; weigh 0.012g of cerium nitrate hexahydrate solution In 10 mL of deionized water, an aqueous solution of cerium nitrate with a concentration of 2.76 mmol/L was obtained; the aqueous solution of cerium nitrate was slowly added dropwise to the initial solution under stirring, and a homogeneous solution was obtained by continuing to stir for 1.5 h.

The dried nickel foam and the homogeneous solution were moved into the reaction kettle for 13 hours at 180°C, the reacted nickel foam was washed with water, washed with ethanol, dried and oxidized at 350°C for 2 hours to obtain a flaky CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode Material.

Example 5

Cut out 30mm × 10mm × 1.5mm nickel foam with a pore size of 110ppi, soak it in 2M HCL for ultrasonic cleaning for 15 minutes, then ultrasonicate in deionized water for 10 minutes, and finally ultrasonicate in absolute ethanol for 10 minutes. The ultrasonicated nickel foam was vacuum-dried at 60 °C for 12 hours.

Weigh 0.055g of sodium dodecyl sulfate, 0.050g of urea, 0.18g of nickel nitrate hexahydrate and 0.18g of cobalt nitrate hexahydrate, dissolved in 20mL of deionized water, stirred for 20min to obtain the initial solution, and weighed 0.01g of cerium nitrate hexahydrate solution. In 10 mL of deionized water, an aqueous solution of cerium nitrate with a concentration of 2.30 mmol/L was obtained; the aqueous solution of cerium nitrate was slowly added dropwise to the initial solution under stirring, and a homogeneous solution was obtained by continuing to stir for 1 h.

The dried nickel foam and the homogeneous solution were moved into the reaction kettle for 10 hours at 170 °C, the reacted nickel foam was washed with water, washed with ethanol, dried and oxidized at 400 °C for 3 hours to obtain a flaky CeO ₂ /Co _1.29 Ni _1.71 O ₄ electrode Material.

Claims (9)

1. Flaky CeO₂/Co_1.29Ni_1.71O₄A method for preparing an electrode material, characterized in that the method comprises the steps of:

(1) cleaning of foamed nickel

Placing the foamed nickel in hydrochloric acid for ultrasonic cleaning, then placing the foamed nickel in deionized water for continuous ultrasonic cleaning, finally placing the foamed nickel in absolute ethyl alcohol for ultrasonic cleaning, and performing vacuum drying to obtain clean foamed nickel;

(2) stirring to obtain uniform solution

Adding sodium dodecyl sulfate, urea, nickel nitrate hexahydrate and cobalt nitrate hexahydrate into deionized water, and stirring to dissolve the sodium dodecyl sulfate, the urea, the nickel nitrate hexahydrate and the cobalt nitrate hexahydrate; adding 10mL of cerium nitrate aqueous solution under stirring, and then continuously stirring to obtain a uniform solution;

the addition amount of the sodium dodecyl sulfate is 0.05-0.055 g, and the mass ratio of cobalt nitrate hexahydrate to nickel nitrate hexahydrate is 1: 1, the adding amount of urea is 0.045-0.055 g, and the concentration of the cerium nitrate aqueous solution is 1.84-3.68 mmol/L;

(3) the foam nickel and the uniform solution are subjected to hydrothermal reaction to obtain a first-step product

Pouring the foamed nickel obtained in the step (1) and the uniform solution obtained in the step (2) into a reaction kettle, carrying out hydrothermal reaction at 170-180 ℃, and obtaining a first-step product after 10-13 h;

(4) washing the product obtained in the first step in the step (3) with water and ethanol, oxidizing the washed product for 2-4 hours at the temperature of 300-400 ℃ to obtain flaky CeO₂/Co_1.29Ni_1.71O₄An electrode material.

2. The production method according to claim 1, wherein in the step (1), the nickel foam has a pore size of 110ppi and a length x width x height of 30mm x 10mm x 1.5 mm.

3. The production method according to claim 1 or 2, wherein in the step (3), the reaction temperature of the hydrothermal reaction is 170 ℃ and the reaction time is 12 hours.

4. The preparation method according to claim 1 or 2, wherein in the step (1), the concentration of hydrochloric acid is 1-2M, the ultrasonic cleaning time is 10-15 min, and the vacuum drying temperature is 50-60 ℃.

5. The preparation method according to claim 3, wherein in the step (1), the concentration of hydrochloric acid is 1-2M, the ultrasonic cleaning time is 10-15 min, and the vacuum drying temperature is 50-60 ℃.

6. The method according to claim 1, 2 or 5, wherein in the step (2), the time for stirring after adding the aqueous solution of cerium nitrate is 60 to 90 min.

7. The preparation method according to claim 3, wherein in the step (2), the time for stirring after adding the aqueous solution of cerium nitrate is 60 to 90 min.

8. The preparation method according to claim 4, wherein in the step (2), the time for stirring after adding the aqueous solution of cerium nitrate is 60 to 90 min.

9. Flake-shaped CeO prepared by the preparation method of any one of claims 1 to 8₂/Co_1.29Ni_1.71O₄The electrode material is characterized in that the electrode material is a three-dimensional reticular foam nickel surface with a longitudinally-grown wrinkled sheet structure, and the sheet structure is uniformly distributed at intervals.

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