Preparation method of pore-adjustable graphene macroscopic bodies used for supercapacitor

A technology of graphene macroscopic body and supercapacitor, which is applied in the direction of graphene and nano-carbon to achieve the effect of low cost and simple process

Inactive Publication Date: 2014-04-16
LIAONING NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Recently, Yang et al. first reduced graphene oxide to soluble graphene, and used this as raw material to obtain graphene two-dimensional film through layer-by-layer self-assembly method, and then soaked the film in different concentrations of sulfuric acid solution to obtain graphene with different pores. Thin films (Science, 2013, 34, 341), so far, there is no report on the preparation method of graphene macroscopic bodies for supercapacitors with adjustable pores

Method used

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  • Preparation method of pore-adjustable graphene macroscopic bodies used for supercapacitor
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  • Preparation method of pore-adjustable graphene macroscopic bodies used for supercapacitor

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Embodiment 1

[0013] as per figure 1 The shown procedure prepares graphene macrobodies.

[0014] a. The preparation concentration is 4.5~8.8 mg mL -1 The neutral graphene oxide solution;

[0015] Using flake graphite as raw material, it is prepared according to the Hummers method or according to the following modified Hummers method:

[0016] Mix 3.0 g of graphite flakes with 72 mL of 98% concentrated sulfuric acid, and stir for 5 min in an ice bath; add 1.5 g of potassium nitrate, and continue to stir in an ice bath for 2 h; slowly add 13.5 g of potassium permanganate, and continue to stir for 2 h. The mixture was then transferred to 35 o C water bath for 30 min, then slowly add 189 mL of distilled water, stir well and raise the water bath temperature to 98 o C and continue stirring for 30 min. After the reaction, take out the beaker, slowly add 219 mL of 60 o C of warm water until the total volume of the solution reaches 480 mL, and cool to room temperature. Finally, 4.2 mL of 30% ...

Embodiment 2

[0020] The preparation method is basically the same as in Example 1, except that the concentration of the obtained neutral graphene oxide solution is 4.5 mg mL -1 , adding sulfuric acid at a concentration of 0.01 mol L -1 , and the reaction time was 3 h. The resulting macrobody has a density of 0.9 g cm -3 , with a pore size of about 0.8 nm.

[0021] Electrochemical performance test: The graphene macroscopic body prepared in Example 2 was made into an electrode according to the method in Example 1, and the constant current charge and discharge and cyclic voltammetry tests were carried out. The test result is: at 100 mA g -1 Specific capacitance at current density is 175 F g -1 ; at 10 mV s -1 The specific capacitance at the scan rate is 123 F g -1 .

Embodiment 3

[0023] The preparation method is basically the same as in Example 1, except that the concentration of the neutral graphene oxide solution is 4.5 mg mL -1 , the concentration of sulfuric acid is 0.3 mol L -1 , and the reaction time was 7 h. The resulting macrobody has a density of 0.14 g cm -3 , with a pore size of about 5.2 nm.

[0024] Electrochemical performance test: The prepared graphene macrobody was made into an electrode according to the method in Example 1, and the constant current charge and discharge and cyclic voltammetry tests were carried out. The test result is: at 100 mA g -1 Specific capacitance at current density is 305 F g -1 ; at 10 mV s -1 Specific capacitance at scan rate is 190 F g -1 .

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Abstract

The invention discloses a method for preparing graphene macroscopic bodies adopting different pore structures and used for a supercapacitor by adjusting sulphuric acid concentration. The method comprises the following steps in sequence: preparing a neutral oxidized graphene solution with the concentration of 4.5-8.8 mg / mL; adding a sulphuric acid solution into the neutral oxidized graphene solution, and mixing uniformly, wherein the volume of the sulphuric acid solution is two times of that of the neutral oxidized graphene solution, and the concentration of the sulphuric acid solution is 0.01-0.45 mol / L; placing a mixed solution in a reaction kettle to react for 3-15 hours at the temperature of 180 DEG C to obtain graphene hydrogel, and drying in a drying cabinet with the temperature of 30 DEG C to obtain the graphene macroscopic bodies. The obtained macroscopic bodies are used for electrode materials of the supercapacitor; the specific capacitance value of the obtained macroscopic bodies can reach 175-322 F / g under the electric current density of 100 mA / g.

Description

technical field [0001] The invention relates to a method for preparing graphene macroscopic bodies with different pore structures for supercapacitors by adjusting the concentration of sulfuric acid, and belongs to the technical field of new electrode materials. Background technique [0002] Supercapacitors have the advantages of fast charging and discharging speed, no pollution to the environment, high power density, wide operating temperature range, etc., and are expected to become a new type of green energy in this century. Graphene, as a potential electrode material for supercapacitors, has many excellent physical and chemical properties such as good electrical conductivity, large specific surface area, high strength and stability, etc. However, monolithic graphene often has different structures and It is in a disorderly distribution state, which affects its excellent performance. Therefore, the formation of the ordered structure system of graphene helps to show its uniq...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04C01B32/184
Inventor 曲江英李玉倩高峰石琳吕思远牛思祺
Owner LIAONING NORMAL UNIVERSITY
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