阅读说明：本技术 一种二氧化锰/碳基柔性电极材料的制备方法 (Preparation method of manganese dioxide/carbon-based flexible electrode material ) 是由 苏利伟 占静 王连邦 吴昊 郑华均 于 2019-08-30 设计创作，主要内容包括：一种二氧化锰/碳基柔性电极材料的制备方法,按照以下步骤进行：(1)将柔性碳基底清洗、烘干；(2)将处理后的碳基底用混酸进行浸渍酸化处理；所述的混酸为浓硝酸和浓硫酸按照体积比1:1～1:6混合而成；(3)配制10～1000mM金属盐水溶液,所述金属盐为高锰酸钾、高锰酸钠、高锰酸锂、高锰酸钡、高锰酸锌中的至少一种；(4)将步骤(2)处理后的碳基底置于金属盐溶液中超声处理20-60min；(5)将步骤(4)超声处理后的混合物进行加热处理；(6)将加热处理后的产物自然冷却到室温,洗涤后真空干燥,得到二氧化锰/碳基柔性电极材料。本发明的制备方法将二氧化锰牢固地附着在柔性碳基体表面,可用于柔性超级电容器,具有较高比容量和良好的循环稳定性。(A preparation method of a manganese dioxide/carbon-based flexible electrode material comprises the following steps: (1) cleaning and drying the flexible carbon substrate; (2) carrying out immersion acidification treatment on the treated carbon substrate by using mixed acid; the mixed acid is formed by mixing concentrated nitric acid and concentrated sulfuric acid according to the volume ratio of 1: 1-1: 6; (3) preparing 10-1000 mM metal salt aqueous solution, wherein the metal salt is at least one of potassium permanganate, sodium permanganate, lithium permanganate, barium permanganate and zinc permanganate; (4) placing the carbon substrate treated in the step (2) in a metal salt solution for ultrasonic treatment for 20-60 min; (5) heating the mixture subjected to the ultrasonic treatment in the step (4); (6) and naturally cooling the heated product to room temperature, washing and then drying in vacuum to obtain the manganese dioxide/carbon-based flexible electrode material. According to the preparation method, the manganese dioxide is firmly attached to the surface of the flexible carbon substrate, so that the flexible carbon substrate can be used for a flexible super capacitor, and has high specific capacity and good cycling stability.)

1. a preparation method of manganese dioxide/carbon-based flexible electrode material is characterized by comprising the following steps: the preparation method comprises the following steps:

(1) Cleaning and drying the flexible carbon substrate;

(2) Carrying out immersion acidification treatment on the carbon substrate treated in the step (1) by using mixed acid; the mixed acid is formed by mixing concentrated nitric acid and concentrated sulfuric acid according to the volume ratio of 1: 1-1: 6;

(3) Weighing metal salt, dissolving the metal salt in deionized water, and stirring uniformly to completely dissolve the metal salt to obtain a metal salt solution; the metal salt is at least one of potassium permanganate, sodium permanganate, lithium permanganate, barium permanganate and zinc permanganate, and the concentration of the metal salt in the metal salt solution is 10-1000 mM;

(4) Placing the carbon substrate treated in the step (2) in the metal salt solution obtained in the step (3) for ultrasonic treatment for 20-60min, and controlling the molar amount of the metal salt in the system to be 0.075-7.5mmol/cm based on the area of the carbon substrate²；

(5) heating the mixture subjected to the ultrasonic treatment in the step (4), wherein the heating temperature is 40-90 ℃, and the treatment time is 0.5-8 h;

(6) And (3) naturally cooling the carbon substrate heated in the step (5) to room temperature, washing, and drying at 40-80 ℃ for 4-12 h in vacuum to obtain the manganese dioxide/carbon-based flexible electrode material.

2. The method of preparing manganese dioxide/carbon-based flexible electrode material according to claim 1, wherein: in the step (1), the flexible carbon substrate is carbon cloth, carbon felt, graphite paper, graphene paper or carbon nanotube paper.

3. the method of preparing manganese dioxide/carbon-based flexible electrode material according to claim 1, wherein: the step (1) is implemented as follows: and ultrasonically cleaning the flexible carbon substrate by using acetone, deionized water and ethanol in sequence, wherein the cleaning time is 10-90 min each time, and the drying temperature is 45-90 ℃.

4. the method of preparing manganese dioxide/carbon-based flexible electrode material according to claim 1, wherein: in the step (2), the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid in the mixed acid is 1: 3.

5. The method of preparing manganese dioxide/carbon-based flexible electrode material according to claim 1, wherein: in the step (2), the acidification treatment is dipping and ultrasonic treatment for 20-60 min.

6. the method of preparing manganese dioxide/carbon-based flexible electrode material according to claim 1, wherein: in the step (3), the concentration of the metal salt in the mixed solution is 20 mM.

7. The method of preparing manganese dioxide/carbon-based flexible electrode material according to claim 1, wherein: in the step (4), the molar dosage of the metal salt in the system is controlled to be 0.15mmol/cm based on the area of the carbon substrate²。

8. The method of preparing manganese dioxide/carbon-based flexible electrode material according to claim 1, wherein: in the step (5), the temperature is 85 ℃, and the heating time is 3 h.

9. The method of preparing manganese dioxide/carbon-based flexible electrode material according to claim 1, wherein: in the step (6), the washing is sequentially washing with deionized water and ethanol; the vacuum drying temperature is 60 ℃, and the time is 8 h.

10. The method of claim 1, wherein the method comprises the steps of:

(1) ultrasonically cleaning a flexible carbon substrate by using acetone, deionized water and ethanol in sequence, wherein the cleaning time is 10-90 min each time, and drying at 45-90 ℃;

(2) placing the flexible carbon substrate treated in the step (1) in concentrated nitric acid: concentrated sulfuric acid is 1:3, soaking and ultrasonic treating for 30 min;

(3) Weighing metal salt, dissolving the metal salt in deionized water, and stirring uniformly to dissolve the metal salt completely to obtain a metal salt solution with the concentration of 20 mM;

(4) Placing the flexible carbon substrate treated by the mixed acid in the step (2) into the metal salt solution prepared in the step (3), and controlling the molar usage of the metal salt in the system to be 0.15mmol/cm based on the area of the carbon substrate²Carrying out ultrasonic treatment for 30 min;

(5) Heating the mixture obtained in the step (4) to 85 ℃ for treatment for 3 h;

(6) and (4) naturally cooling the carbon substrate heated in the step (5) to room temperature, washing the carbon substrate with deionized water and absolute ethyl alcohol in sequence, and drying the carbon substrate for 8 hours in vacuum at the temperature of 60 ℃ to obtain the manganese dioxide/carbon-based flexible electrode material.

Technical Field

the invention relates to a preparation method of a novel manganese dioxide/carbon-based flexible electrode material.

Background

As a new energy storage device, the super capacitor has higher power density, shorter charge-discharge time and longer cycle life than a battery, and has good application prospect. With the development of duet and economy, flexible and portable electronic equipment can be seen everywhere in human life in the future, so that the research and development of high-performance mobile power supplies are of great significance. Nowadays, how to further improve the quality and the volume specific capacitance of the mobile power supply and ensure high energy and power output is a main problem facing us. It is not desirable to carry a heavy mobile power supply to meet our demand for energy, so the mass and volume of the mobile power supply can be further miniaturized. Through research and development in recent years, flexible electronic devices have become mature and perfect, but development of corresponding flexible mobile power supplies has lagged behind. The flexibility of the super capacitor needs to be started from the structure, and the electrode material and the ion transmission mechanism of the super capacitor are improved, so that the super capacitor has stable electrochemical performance as the common super capacitor under the flexible and bendable condition. The electrode material is the key for determining the performance of the super capacitor, so the research on the preparation method and the thought of the electrode material has important significance for exploring a composite electrode material with a novel structure.

The metal oxide generates oxidation-reduction reaction at the interface of the electrode solution through valence state change, and can generate Faraday capacitance, so the metal oxide is always a research hotspot of electrode materials. The metal oxide electrode material mainly includes ruthenium oxide, nickel oxide, cobalt oxide, manganese oxide, iron oxide, and the like. Among them, manganese oxide is considered as an electrode material with great research prospects due to its higher theoretical specific capacity, wide resources, low price, environmental friendliness and multiple oxidation states. The manganese oxide which is most studied at present is manganese dioxide electrode material which shows good capacitance characteristics in a neutral electrolyte and has a wide potential window. The energy storage mechanism of manganese dioxide is that the surface and the interior of an electrode in electrolyte generate a Faraday reaction process, the Faraday reaction on the surface is mainly the adsorption of cations, and the Faraday reaction in the electrode is realized by the intercalation and the deintercalation of the cations in the electrolyte.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the preparation method of the manganese dioxide/carbon-based flexible electrode material, which has the advantages of low preparation cost, simple and convenient process, safe and reliable operation, no toxic and harmful chemicals and suitability for large-scale green development.

in order to achieve the purpose, the invention adopts the following technical scheme:

A preparation method of a manganese dioxide/carbon-based flexible electrode material comprises the following steps:

(1) cleaning and drying the flexible carbon substrate;

(2) carrying out immersion acidification treatment on the carbon substrate treated in the step (1) by using mixed acid; the mixed acid is formed by mixing concentrated nitric acid and concentrated sulfuric acid according to the volume ratio of 1: 1-1: 6;

(3) Weighing metal salt, dissolving the metal salt in deionized water, and stirring uniformly to completely dissolve the metal salt to obtain a metal salt solution; the metal salt is at least one of potassium permanganate, sodium permanganate, lithium permanganate, barium permanganate and zinc permanganate, and the concentration of the metal salt in the metal salt solution is 10-1000 mM;

(4) Placing the carbon substrate treated in the step (2) in the metal salt solution obtained in the step (3) for ultrasonic treatment for 20-60min, and controlling the molar amount of the metal salt in the system to be 0.075-7.5mmol/cm based on the area of the carbon substrate²；

(5) Heating the mixture subjected to the ultrasonic treatment in the step (4), wherein the heating temperature is 40-90 ℃, and the treatment time is 0.5-8 h;

(6) And (3) naturally cooling the carbon substrate heated in the step (5) to room temperature, washing, and drying at 40-80 ℃ for 4-12 h in vacuum to obtain the manganese dioxide/carbon-based flexible electrode material.

the core of the preparation method is that manganese dioxide nano-sheets with uniform size and controllable size and thickness are formed on the surfaces of different flexible carbon substrates by changing the types and concentration of metal salts and the temperature and time of heating treatment.

in step (1) of the present invention, the flexible carbon substrate has excellent conductivity, and is preferably a carbon cloth, a carbon felt, a graphite paper, a graphene paper or a carbon nanotube paper, and these flexible carbon substrate materials can be obtained by purchasing commercially available products or preparing them according to the methods disclosed in the prior documents. Preferably, step (1) is carried out as follows: and ultrasonically cleaning the carbon substrate by using acetone, deionized water and ethanol in sequence, wherein the cleaning time is 10-90 min each time, and the drying temperature is 45-90 ℃.

in the step (2), the oxygen-containing functional groups on the surface of the carbon substrate are increased after the mixed acid is acidified, so that the loading capacity of the metal oxide can be increased. The degree of acidification of the carbon substrate is affected by the mixed acid solution in different proportions, preferably in the proportions of concentrated nitric acid: concentrated sulfuric acid is 1: 3. Preferably, the acidification treatment is dipping ultrasound for 20-60min, and more preferably 30 min.

in the step (3) of the invention, the metal salts with different concentrations can influence the size, thickness and loading amount of the manganese dioxide nanosheets. Preferably, the metal salt is potassium permanganate, sodium permanganate, lithium permanganate, barium permanganate or zinc permanganate. The concentration of the metal salt in the mixed solution affects the size of the manganese dioxide nanosheets, with the higher the concentration of the metal salt, the larger the size of the nanosheets, and most preferably the concentration of the metal salt in the mixed solution is 20 mM.

In the step (4) of the invention, the molar amount of the metal salt in the system is controlled to be 0.15mmol/cm based on the area of the carbon substrate²。

In step (4) of the present invention, the ultrasonic treatment time is preferably 30 min.

In the step (5), the size and the crystal form of the manganese dioxide nanosheet can be influenced by the heating treatment temperature, the higher the temperature is, the smaller the size of the nanosheet is, and the most preferable high temperature is 85 ℃; the heating treatment time affects the size and loading of the manganese dioxide nanosheets, with shorter times, smaller nanometer sizes and lower loadings, with a heating time of 3 hours being most preferred.

in step (6) of the present invention, the washing is preferably carried out by sequentially washing with deionized water and ethanol; the vacuum drying temperature is preferably 60 ℃ and the time is preferably 8 h.

The invention particularly preferably relates to a preparation method which comprises the following steps:

(1) Ultrasonically cleaning a flexible carbon substrate by using acetone, deionized water and ethanol in sequence, wherein the cleaning time is 10-90 min each time, and drying at 45-90 ℃;

(2) Placing the flexible carbon substrate treated in the step (1) in concentrated nitric acid: concentrated sulfuric acid is 1:3, soaking and ultrasonic treating for 30 min;

(3) weighing metal salt, dissolving the metal salt in deionized water, and stirring uniformly to dissolve the metal salt completely to obtain a metal salt solution with the concentration of 20 mM;

(4) Placing the flexible carbon substrate treated by the mixed acid in the step (2) into the metal salt solution prepared in the step (3), and controlling the molar usage of the metal salt in the system to be 0.15mmol/cm based on the area of the carbon substrate²carrying out ultrasonic treatment for 30 min;

(5) Heating the mixture obtained in the step (4) to 85 ℃ for treatment for 3 h;

(6) and (4) naturally cooling the carbon substrate heated in the step (5) to room temperature, washing the carbon substrate with deionized water and absolute ethyl alcohol in sequence, and drying the carbon substrate for 8 hours in vacuum at the temperature of 60 ℃ to obtain the manganese dioxide/carbon-based flexible electrode material.

The nano manganese dioxide/carbon-based flexible electrode material prepared by the method can be used for flexible super capacitors.

Compared with the prior art, the invention has the following characteristics and advantages:

(1) the invention relates to a flexible electrode material prepared by using different types of carbon substrates as flexible substrates by utilizing water bath heating which is simple to operate and is safe and controllable. The preparation method firmly attaches the manganese dioxide nano-sheet on the surface of the carbon substrate with excellent conductivity, so that the carbon substrate has good conductivity; the size and the distribution of manganese dioxide can be regulated and controlled, the electrode material has good chemical stability due to the in-situ growth of the nanosheets, the preparation processes such as tabletting and coating are reduced, a binder and a conductive agent are not needed, the preparation cost is low, the process is simple and convenient, the operation is safe and reliable, the use of toxic and harmful chemicals is not involved, and the method is suitable for large-scale green development.

(2) The prepared flexible electrode material improves the conductivity and stability of the manganese dioxide electrode material, the contact area between the nanosheet and an electrolyte is increased due to the lamellar structure of the nanosheet, and the manganese dioxide/carbon cloth composite material in the electrolyte has high specific capacity and good cycling stability.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention.

fig. 1 is a Scanning Electron Microscope (SEM) image of the flexible base carbon cloth of example 1.

FIG. 2 shows MnO prepared in example 1₂SEM image of/carbon cloth electrode.

FIG. 3 shows MnO prepared in example 1₂SEM image of/carbon cloth electrode under high magnification.

FIG. 4 shows MnO prepared in example 1₂X-ray diffraction (XRD) pattern of/carbon cloth electrode.

FIG. 5 shows MnO prepared in example 1₂Transmission Electron Microscopy (TEM) images of/carbon cloth electrodes.

FIG. 6 shows MnO prepared in example 1₂Cyclic Voltammetry (CV) plot for carbon cloth electrode.

FIG. 7 shows MnO prepared in example 1₂Constant current charge and discharge (GCD) diagram of/carbon cloth electrode.

FIG. 8 shows MnO prepared in example 1₂long cycle performance diagram of carbon cloth electrode.

Fig. 9 is an SEM image of the flexible substrate carbon felt of example 2.

FIG. 10 shows MnO prepared in example 2₂SEM image of/carbon felt electrode under high magnification.

FIG. 11 is a block diagramMnO prepared in example 2₂GCD diagram of/carbon felt electrode.

FIG. 12 is MnO prepared in example 3₂TEM images of graphene paper electrodes.

FIG. 13 shows MnO prepared in example 3₂GCD diagram of graphene paper electrode.

FIG. 14 shows MnO prepared in example 4₂GCD diagram of graphite paper electrode.

FIG. 15 shows MnO prepared in example 5₂GCD diagram of/carbon nanotube paper electrode.

Detailed Description

the technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments, but is not limited thereto:

In the embodiment of the invention, CV and GCD tests of the manganese dioxide/carbon-based flexible composite electrode are completed in an electrochemical workstation, a three-electrode system is adopted, an electrolyte is a 1M sodium sulfate solution, a reference electrode is a saturated calomel electrode, and a counter electrode is a platinum electrode.