Preparation method of nickel-cobalt hydroxide / carbon composite electrode material

Abstract

The invention relates to the field of new energy materials, and discloses a preparation method of a nickel-cobalt hydroxide / carbon composite electrode material, which comprises the following steps: S1, adding a carbon nanotube into ionized water, and uniformly stirring; s2, adding the graphene oxide into the deionized water; s3, weighing nickel sulfate hexahydrate, cobalt sulfate heptahydrate and urea; s4, adding the solution in S3 into deionized water, and stirring; s5, adding the solutions in the S1 and S2 into the solution in the S4, performing ultrasonic treatment, and fully stirring; s6, transferring the mixed solution in the step S5 into a hydrothermal reaction kettle for hydrothermal reaction, and naturally cooling after the reaction is finished; s7, collecting a reaction product, washing and drying to obtain powder; according to the nickel-cobalt hydroxide / carbon composite electrode material prepared by the invention, the problem of structural stability of the nickel-cobalt hydroxide in the rapid charging and discharging process is solved, and the service life of the material is greatly prolonged; the specific surface area and the conductivity are higher.

Description

Technical Field

[0001] The present invention relates to the field of new energy materials, and more specifically, to a method for preparing a nickel-cobalt hydroxide / carbon composite electrode material. Background Art

[0002] In the field of electrochemical energy storage, nickel cobalt hydroxide has attracted much attention due to its excellent electrochemical activity. However, after multiple rapid charge and discharge cycles, the capacitance of traditional nickel cobalt hydroxide electrode materials often decreases rapidly due to volume expansion and structural damage, which seriously restricts its performance in practical applications. This problem needs to be solved urgently. Summary of the invention

[0003] The present invention provides a method for preparing a nickel cobalt hydroxide / carbon composite electrode material. The prepared nickel cobalt hydroxide / carbon composite electrode material effectively inhibits the stacking of graphene sheets and the aggregation of carbon nanotubes, while enhancing the specific surface area and conductivity of the material.

[0004] The present invention provides a method for preparing a nickel-cobalt hydroxide / carbon composite electrode material, comprising the following steps:

[0005] S1, adding carbon nanotubes into ionized water and stirring evenly to form a stable solution;

[0006] S2, adding graphene oxide to deionized water and ultrasonically treating the water to form a uniform solution;

[0007] S3, weighing nickel sulfate hexahydrate, cobalt sulfate heptahydrate, and urea, and stirring to form a uniform solution;

[0008] S4, adding the solution in S3 into deionized water and stirring to form a uniform solution;

[0009] S5, adding the solutions in S1 and S2 to the S4 solution, performing ultrasonic treatment, and then magnetically stirring to fully mix;

[0010] S6, transferring the mixed solution in S5 to a hydrothermal reactor for hydrothermal reaction, and allowing the hydrothermal reactor to cool naturally to room temperature after the reaction is completed;

[0011] S7, collecting the reaction product, washing it with deionized water and anhydrous ethanol for multiple times, and drying it to obtain a powder;

[0012] Furthermore, in step S1, a magnetic stirrer is used for stirring for 30 minutes.

[0013] Further, in step S2, the solution is ultrasonically treated for 1 h.

[0014] Further, in step S3, the solution is stirred in a magnetic stirrer for 1 h.

[0015] Further, in step S4, the solution is stirred in a magnetic stirrer for 1 hour until the solid matter is completely dissolved.

[0016] Further, in step S5, the ultrasonic treatment is performed for 10 minutes and then magnetic stirring is performed for 1 hour.

[0017] Furthermore, in step S6, the reactor is lined with polytetrafluoroethylene and subjected to hydrothermal treatment at 120°C for 12 hours.

[0018] Beneficial effects of the present invention:

[0019] 1. The nickel-cobalt hydroxide / carbon composite electrode material solves the structural stability problem of nickel-cobalt hydroxide during rapid charging and discharging, greatly extending the service life of the material; secondly, the optimized composite material exhibits a higher specific surface area and conductivity, thereby achieving better capacitance performance and rate characteristics in practical applications.

[0020] 2. The present invention uses urea as a precipitant to form a complex between the hydroxyl and amide groups in the solution and the nickel-cobalt ions through precipitation, and then accelerates the reaction rate through hydrothermal treatment. The prepared nickel-cobalt hydroxide has a unique sea urchin-like and coral-like structure and has a large specific surface area and specific capacitance.

[0021] 3. The present invention adopts a hydrothermal method to prepare nickel cobalt hydroxide / carbon composite electrode material. The present invention adopts a hydrothermal method to prepare nickel cobalt hydroxide / carbon composite electrode material carbon quantum dots, which effectively limits the structural accumulation of the material, reduces the resistance to ion transmission, protects the environment, and is easy to operate. After the hydrothermal reaction, pure composite material powder can be obtained through washing and drying steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the carbon nanotubes in the present invention;

[0023] Figure 2 is a graphene structure diagram of the present invention;

[0024] Figure 3 This is the synthesis step of NiCo / CNTs-GO in the present invention;

[0025] Figure 4 is a SEM image of NiCo / CNTs-GO in the present invention;

[0026] Figure 5 is the TEM image (100 nm) of NiCo / CNTs-GO in the present invention;

[0027] Figure 6 is the TEM image (50 nm) of NiCo / CNTs-GO in the present invention. DETAILED DESCRIPTION

[0028] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0029] Example 1

[0030] In this embodiment, a method for preparing a nickel-cobalt hydroxide / carbon composite electrode material is proposed, comprising the following steps:

[0031] S1, adding carbon nanotubes into ionized water and stirring evenly to form a stable solution;

[0032] S2, adding graphene oxide to deionized water and ultrasonically treating the water to form a uniform solution;

[0033] S3, weighing nickel sulfate hexahydrate, cobalt sulfate heptahydrate, and urea, and stirring to form a uniform solution;

[0034] S4, adding the solution in S3 into deionized water and stirring to form a uniform solution;

[0035] S5, adding the solutions in S1 and S2 to the S4 solution, performing ultrasonic treatment, and then magnetically stirring to fully mix;

[0036] S6, transferring the mixed solution in S5 to a hydrothermal reactor for hydrothermal reaction, and allowing the hydrothermal reactor to cool naturally to room temperature after the reaction is completed;

[0037] S7, collecting the reaction product, washing it with deionized water and anhydrous ethanol for multiple times, and drying it to obtain a powder.

[0038] in:

[0039] In step S1, a magnetic stirrer is used for stirring for 30 minutes.

[0040] In step S2, the solution was sonicated for 1 h.

[0041] In step S3, the solution was stirred in a magnetic stirrer for 1 h.

[0042] In step S4, the solution is stirred in a magnetic stirrer for 1 h until the solid matter is completely dissolved.

[0043] In step S5, ultrasonic treatment was performed for 10 min and then magnetic stirring was performed for 1 h.

[0044] In step S6, the reactor is lined with polytetrafluoroethylene and subjected to hydrothermal treatment at 120°C for 12 hours.

[0045] Example 2

[0046] In this embodiment, the method in Embodiment 1 is used to prepare a nickel-cobalt hydroxide / carbon composite electrode material with enhanced cycle stability, and the specific process is as follows:

[0047] S1, weigh 89 mg of carbon nanotubes (CNTs), add them into 20 ml of deionized water and stir for 30 min to form a mixed solution;

[0048] S2, weigh 8.9 mg of graphene oxide (GO), add it to 20 ml of deionized water, and ultrasonicate for 1 h to form a uniform GO suspension;

[0049] S3, weigh 1.5 mmol of nickel sulfate hexahydrate, 1.5 mmol of cobalt sulfate heptahydrate, and 18 mmol of urea, and stir for 1 h until completely dissolved;

[0050] S4, add the solution in S3 to 20 ml of deionized water and stir magnetically for 1 h until all solid matter is completely dissolved to form a uniform solution.

[0051] S5, adding the solutions in S1 and S2 to the S4 solution, ultrasonically treating for 10 min, and then magnetically stirring for 1 h to fully mix;

[0052] S6, transferring the mixed solution in S5 to a polytetrafluoroethylene-lined hydrothermal reactor for hydrothermal reaction at 120°C for 12 hours, and allowing the hydrothermal reactor to cool naturally to room temperature after the reaction is completed;

[0053] S7, collecting the reaction product, separating the solid precipitate by filtering, washing the precipitate with deionized water and anhydrous ethanol for multiple times to remove unreacted raw materials and by-products, and drying the washed precipitate at 70° C. for 12 hours to obtain NiCo / CNTs-GO composite material powder.

[0054] Figure 1 is a schematic diagram of the carbon nanotubes in the present invention, Figure 2 is a graphene structure diagram in the present invention, Figure 3 This is the synthesis step of NiCo / CNTs-GO in the present invention. Figure 4 is the SEM image of NiCo / CNTs-GO in the present invention, Figure 5 is the TEM image (100 nm) of NiCo / CNTs-GO in the present invention, Figure 6is the TEM image (50 nm) of NiCo / CNTs-GO in the present invention.

[0055] The nickel cobalt hydroxide / carbon composite electrode material prepared in this embodiment solves the problem of structural stability of nickel cobalt hydroxide during rapid charging and discharging, greatly extending the service life of the material; secondly, the optimized composite material exhibits higher specific surface area and conductivity, thereby achieving more superior capacitance performance and rate characteristics in practical applications.

[0056] Using urea as a precipitant, the hydroxyl and amide groups in the solution are precipitated to form a complex with the nickel-cobalt ions, and then the reaction rate is accelerated by hydrothermal treatment. The prepared nickel-cobalt hydroxide has a unique sea urchin and coral structure with a large specific surface area and specific capacitance.

[0057] The present invention adopts a hydrothermal method to prepare a nickel cobalt hydroxide / carbon composite electrode material. The present invention adopts a hydrothermal method to prepare a nickel cobalt hydroxide / carbon composite electrode material carbon quantum dots, which effectively limits the structural accumulation of the material, reduces the resistance to ion transmission, protects the environment, and is easy to operate. After the hydrothermal reaction, a pure composite material powder can be obtained through the steps of washing and drying.

[0058] The above describes an embodiment of the present embodiment, but the present embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present embodiment, ordinary technicians in this field can also make many forms, all of which are within the protection of the present embodiment.

Claims

1. A method for preparing a nickel-cobalt hydroxide / carbon composite electrode material, characterized in that: The following steps are involved: S1, adding carbon nanotubes into ionized water and stirring evenly to form a stable solution; S2, adding graphene oxide to deionized water and ultrasonically treating the water to form a uniform solution; S3, weighing nickel sulfate hexahydrate, cobalt sulfate heptahydrate, and urea, and stirring to form a uniform solution; S4, adding the solution in S3 into deionized water and stirring to form a uniform solution; S5, adding the solutions in S1 and S2 to the S4 solution, performing ultrasonic treatment, and then magnetically stirring to fully mix; S6, transferring the mixed solution in S5 to a hydrothermal reactor for hydrothermal reaction, and allowing the hydrothermal reactor to cool naturally to room temperature after the reaction is completed; S7, collecting the reaction product, washing it with deionized water and anhydrous ethanol for multiple times, and drying it to obtain a powder.

2. The method for preparing a nickel-cobalt hydroxide / carbon composite electrode material according to claim 1, characterized in that: In step S1, a magnetic stirrer is used for stirring for 30 minutes.

3. The method for preparing a nickel-cobalt hydroxide / carbon composite electrode material according to claim 1, characterized in that: In step S2, the solution was sonicated for 1 h.

4. The method for preparing a nickel-cobalt hydroxide / carbon composite electrode material according to claim 1, characterized in that: In step S3, the solution was stirred in a magnetic stirrer for 1 h.

5. The method for preparing a nickel-cobalt hydroxide / carbon composite electrode material according to claim 1, characterized in that: In step S4, the solution is stirred in a magnetic stirrer for 1 h until the solid matter is completely dissolved.

6. The method for preparing a nickel-cobalt hydroxide / carbon composite electrode material according to claim 1, characterized in that: In step S5, ultrasonic treatment was performed for 10 min and then magnetic stirring was performed for 1 h.

7. The method for preparing a nickel-cobalt hydroxide / carbon composite electrode material according to claim 1, characterized in that: In step S6, the reactor is lined with polytetrafluoroethylene and subjected to hydrothermal treatment at 120°C for 12 hours.

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