A graphene-loaded flower-like manganese dioxide composite material and its ultrasonic synthesis method

A technology of manganese dioxide and composite materials, which is applied in the field of electrochemistry and material synthesis, can solve the problems of reduced charge and discharge capacity, unstable manganese cycle, and low electronic conductance, and achieve improved capacitance performance, super thermal conductivity and ductility, big yield effect

Active Publication Date: 2015-08-12
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there are many problems with manganese dioxide as an electrode material for electrochemical capacitors, mainly including: (1) the actual capacity is much smaller than the theoretical capacity; Decreased discharge capacity; (3) cycle instability caused by manganese dissolution

Method used

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  • A graphene-loaded flower-like manganese dioxide composite material and its ultrasonic synthesis method
  • A graphene-loaded flower-like manganese dioxide composite material and its ultrasonic synthesis method
  • A graphene-loaded flower-like manganese dioxide composite material and its ultrasonic synthesis method

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Effect test

Embodiment 1

[0031] Embodiment one : Preparation of graphene-loaded flower-like manganese dioxide composites with manganese acetate as manganese source.

[0032] Potassium persulfate (K 2 S 2 o 8 ) 2.5 g, phosphorus pentoxide (P 2 o 5 ) 2.5 g, dissolved in 12 mL of concentrated sulfuric acid, heated to 80°C; then 3 g of natural graphite was added to the above solution, kept at 80°C for 4.5 hours; cooled to room temperature, diluted with 500 mL of deionized water, and left standing overnight ; filter, float residual acid with 0.2 mm filter; dry in a vacuum oven at 60°C; add the obtained preoxide to 120 mL of ice-bathed concentrated sulfuric acid, slowly add 15 g of KMnO under stirring 4 , Keep the temperature below 20°C during the addition process. Then the temperature was controlled at 35°C and stirred for 2 h. Add 250 mL of deionized water to dilute, and keep the temperature below 50°C in an ice bath during the dilution process. Stir for another 2 h, add 0.7 L of deionized water,...

Embodiment 2

[0036] Embodiment two : Preparation of graphene-loaded flower-like manganese dioxide composites with manganese nitrate as manganese source.

[0037]Take 0.259 g of manganese nitrate and add 50 mL of deionized water, add 50 mg of graphene to it, stir for 15 min, ultrasonicate for 0.5 h, add an appropriate amount of 0.3 mol / L hydrochloric acid to it to make the pH of the solution = 1.5, and then stir for 0.5 h. Under ultrasonic conditions, slowly drop 75mL of 9.2 mol / L potassium permanganate solution into the above solution. At 20°C, continue to sonicate for 12h. Centrifuge, wash with alcohol, and wash with water three times each to obtain the product.

[0038] The scanning electron microscope photograph of the product is shown in figure 2 , it can be seen from the figure that the flower-like manganese dioxide has a size of 200-300 nm and is evenly loaded on the surface of graphene without obvious agglomeration. The prepared material was electrochemically tested, and the ...

Embodiment 3

[0039] Embodiment Three : Preparation of graphene-loaded flower-like manganese dioxide composites with manganese chloride as manganese source.

[0040] Take 0.205g of manganese chloride and add it to 50 mL of deionized water, add 50 mg of graphene to it, stir for 15 min, sonicate for 0.5 h, add an appropriate amount of 0.3 mol / L hydrochloric acid to it to make the pH of the solution = 2.5, and then stir 0.5 h. Under ultrasonication, slowly drop 75 mL of 9.2 mol / L potassium permanganate solution into the above solution. At 50°C, continue to sonicate for 4h. Centrifuge, wash with alcohol, and wash with water three times each to obtain the product.

[0041] The transmission electron microscope photograph of the product is shown in image 3 , it can be seen that the flower-like manganese dioxide with a diameter of 100-300 nm is evenly loaded on the surface of graphene, and no obvious agglomeration phenomenon is seen. And several particles are covered by a layer of transparen...

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Abstract

The invention relates to a graphene load flower manganese dioxide (MnO2) composite material and an ultrasonic synthetic method thereof. The graphene load flower MnO2 composite material is characterized in that flower MnO2 is composite with graphene layers, and the flower MnO2 is composed of a plurality of flakes which are mutually assembled. Graphene is used as a matrix skeleton and has favorable conductibility, and the flower MnO2 can have favorable conductibility through the graphene layers, thereby increasing the apparent conductivity of the composite material. The diameter of the flower MnO2 growing on both sides of the graphene is from 100 to 300 nm, and the thickness of each flake is from 1 to 10 nm. The material is prepared by the following two typical steps of preparing pyrolytic graphene and ultrasonically synthesizing the graphene load flower MnO2 composite material. The graphene load flower MnO2 composite material prepared by using the ultrasonic synthetic method has the advantages of simple process, high electrode capacitance and good cycle performance and is suitable for electrode materials of super capacitors.

Description

technical field [0001] The invention relates to a graphene three-dimensional composite material used as a supercapacitor, in particular to a graphene-loaded flower-shaped manganese dioxide composite material and an ultrasonic synthesis method thereof, belonging to the fields of electrochemistry and material synthesis. Background technique [0002] As a component for storing electrical energy, capacitors account for more than 10% of the world's electronic components. The development of capacitors has gone through several stages of electrolytic capacitors, ceramic capacitors, organic film capacitors and electrochemical capacitors. However, in general, capacitors store relatively little energy. As a relatively new type of energy storage device, electrochemical capacitors have important and broad application prospects in the fields of mobile communications, electric vehicles, aerospace and national defense technology, and thus have attracted great attention worldwide. [0003]...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01G11/32H01G11/86
CPCY02E60/13
Inventor 蒋永赵兵马启亮蔡新辉刘瑞喆凌学韬焦正
Owner SHANGHAI UNIV
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