Graphene-cladding manganese dioxide combination electrode material and method for producing same

A technology of graphene coating and manganese dioxide, which is applied in hybrid capacitor electrodes, hybrid/electric double layer capacitor manufacturing, circuits, etc., can solve problems such as unsatisfactory cycle performance, easy agglomeration, and affecting performance, so as to increase cycle Stability, prevent agglomeration, increase the effect of specific capacity

Inactive Publication Date: 2012-10-03

UNIV OF ELECTRONIC SCI & TECH OF CHINA

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AI-Extracted Technical Summary

Problems solved by technology

However, graphene materials are prone to agglomeration during the preparation process, which seriously affects its own performance.

Among Faraday capacitor electrode materials, manganese oxide has attracted a lot of a...

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Abstract

A graphene-cladding manganese dioxide combination electrode material and a method for producing the same, belonging to the technical field of electronic functional materials, the graphene-cladding manganese dioxide combination electrode material comprises nano manganese dioxide particles and graphene cladded with manganese dioxide particles, wherein the mass ratio of graphene and the nano manganese dioxide particles is 1:(1.25-10). The method comprises the following steps: preparing the nano manganese dioxide particles and graphite oxide respectively, and mixing and ultrasonically dispersing to obtain the graphene-cladding manganese dioxide dispersing agent, finally, reducing the graphite oxide to obtain the graphene-cladding manganese dioxide combination electrode material. The graphene is used to clad the manganese dioxide, so the electrical conductivity and cycling stability of the electrode material parts can be improved; and meanwhile, the existence of the manganese dioxide particles also effectively prevents the graphene from reunion, so the specific capacity of the electrode material of a supercapacitor is obviously increased. The method has a simple technology, reaction products are easy to control, the purity is high, and the produced combination electrode material is suitable for producing an electrode plate of the supercapacitor.

Application Domain

Electrolytic capacitorsHybrid capacitor electrodes +1

Technology Topic

Cvd grapheneNanometre +10

Image

Examples

Experimental program(5)
Comparison scheme(1)

Example Embodiment

[0026] Example 1

[0027] The reactants were mixed according to the ratio of 12ml of concentrated sulfuric acid, 5g of potassium persulfate and 5g of phosphorus pentoxide per 10g of flake graphite, reacted at 80°C for 4.5 hours and then cooled to room temperature naturally, then diluted with distilled water, filtered, and washed until Neutral, naturally dried to obtain pre-oxidized graphite; according to the ratio of 72 ml of concentrated sulfuric acid and 30 g of potassium permanganate per 10 grams of pre-oxidized graphite, slowly add pre-oxidized graphite to the concentrated sulfuric acid of the ice-water bath, and then slowly add potassium permanganate, Stir the reaction for 10 to 20 minutes under the condition that the temperature does not exceed 20 °C, then heat up to 35 °C and continue to stir and react for 2 hours, then slowly add deionized water, heat up to 95 °C, and continue stirring for 30 minutes. After the reaction, add an appropriate amount of hydrogen peroxide to reduce the residual Oxidant, the solution turned bright yellow, filtered while hot, and washed with 5% HCl solution to remove metal ions, then washed with deionized water to neutralize filtration, and finally placed the filter cake in a vacuum drying oven at 50 ° C to fully dry, Graphite oxide is obtained.

[0028]Weigh 0.632g of potassium permanganate and dissolve it in 30ml of deionized water to obtain a potassium permanganate solution; weigh 0.706g of ascorbic acid and dissolve it in 20ml of deionized water to obtain a portion of ascorbic acid solution; then add a portion of potassium permanganate to After the solution was mixed with a part of ascorbic acid solution, the reaction was stirred at room temperature for 30 minutes, washed three times with distilled water and absolute ethanol, and finally dried in a drying oven at 90° C. for 12 hours to obtain nano-manganese dioxide particles. The obtained nano-manganese dioxide particles are α-type nano-manganese dioxide particles (PDF Card: 44-0141)

[0029] Weigh 100mg of graphite oxide and dissolve it in 100ml of distilled water, ultrasonically dissolve it completely to form a graphene oxide dispersion, add 2.5mg of LD dispersant (Shenzhen Haichuan Chemical Technology Co., Ltd.), according to the mass ratio of graphene oxide and manganese dioxide To 1:2.5, add 250 mg of freshly prepared α-type nano-manganese dioxide particles, and ultrasonically form a uniformly dispersed graphene oxide/manganese dioxide solution.

[0030] To the mixed solution of graphene oxide and manganese dioxide, add 1.2ml of 80% hydrazine hydrate solution, heat and stir to reflux until complete reaction, solid-liquid separation, washing and drying to obtain graphene-coated manganese oxide composite electrode material (see image 3 ).

[0031] The prepared graphene-coated manganese dioxide nanocomposite, acetylene black and binder (5% PTFE emulsion) were mixed in a mass ratio of 85:10:5, and ultrasonically dispersed after adding a certain amount of anhydrous ethanol. Homogeneous, and demulsification treatment was performed in a 65°C water bath. Finally, the treated electrode material was evenly coated on the cleaned nickel foam, impacted into an electrode sheet with a diameter of 8mm, placed in a vacuum drying oven at 85°C for drying for 12h, and then pressed with a tablet press under a pressure of 5MPa for 5min After weighing, two electrode sheets with similar mass were selected to assemble a symmetrical supercapacitor with 1M/L NaSO 4 The solution was used as the electrolyte, and the two-electrode system was used to perform cyclic voltammetry and AC impedance tests on the CHI660D electrochemical workstation, and the constant current charge-discharge test and cycle stability test of the capacitor were performed using the LAND battery test system.

[0032] Calculate the specific capacity of the electrode material from the formula Cs=2S/ΔVγm (Cs is the specific capacity of a single electrode, s is the integral area of the CV map, ΔV is the potential window, γ is the scanning speed, m is the total mass of the active material of the electrode sheet) , the results show that the graphene-coated manganese dioxide nanocomposites have a specific capacity of 235 F/g at a scan speed of 10 mV/s (see Figure 4 ), and the capacity retention rate was 87% after 1000 cycles of testing.

Example Embodiment

[0033] Example 2

[0034] The preparation steps of graphite oxide and α-type manganese dioxide are the same as those in Example 1.

[0035] Take 100mg of graphite oxide and dissolve it in 100ml of distilled water, ultrasonically make it completely dissolved form graphene oxide solution, add 2.5mg LD dispersant, according to the ratio of the mass of graphene oxide to the mass of manganese oxide is 1:1.3, add 130mg just prepared The nano-manganese dioxide particles are ultrasonically formed into a uniformly dispersed graphene oxide/manganese dioxide solution.

[0036] To the mixed solution of graphene oxide and manganese dioxide, add 1.2 ml of 80% hydrazine hydrate solution, heat and stir to reflux until complete reaction, solid-liquid separation, washing and drying to obtain graphene-coated manganese oxide composite electrode material.

[0037] The implementation steps of the electrochemical performance test are the same as those in Example 1. The results show that it has a specific capacity of 167F/g at a scanning speed of 10mV/s, and after 1000 cycles of testing, the capacity retention rate is 83%.

Example Embodiment

[0038] Example 3

[0039] The preparation steps of graphite oxide and α-type manganese dioxide are the same as those in Example 1.

[0040] Get 100mg of graphite oxide and dissolve it in 100ml of distilled water, ultrasonically make it completely dissolved form graphene oxide solution, add 2.5mg LD dispersant, according to the ratio of the mass of graphene oxide to the mass of manganese oxide is 1:9, add 900mg just prepared The nano-manganese dioxide particles are ultrasonically formed into a uniformly dispersed graphene oxide/manganese dioxide solution.

[0041] To the mixed solution of graphene oxide and manganese dioxide, add 1.2 ml of 80% hydrazine hydrate solution, heat and stir to reflux until complete reaction, solid-liquid separation, washing and drying to obtain graphene-coated manganese oxide composite electrode material.

[0042] The implementation steps of the electrochemical performance test are the same as those in Example 1. The results show that it has a specific capacity of 187F/g at a scanning speed of 10mV/s, and after 1000 cycles of testing, the capacity retention rate is 80%.

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Description & Claims & Application Information

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Graphene-cladding manganese dioxide combination electrode material and method for producing same

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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