CN110600278B

CN110600278B - Pinecone-shaped MnO2Ball/foam carbon composite material and preparation method thereof

Info

Publication number: CN110600278B
Application number: CN201910778665.8A
Authority: CN
Inventors: 严学华; 袁小雪; 周辰; 王静静; 程晓农
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2019-08-22
Filing date: 2019-08-22
Publication date: 2022-03-22
Anticipated expiration: 2039-08-22
Also published as: CN110600278A

Abstract

The invention relates to a super capacitor, in particular to pinecone-shaped MnO₂Ball/foam carbon composite material and its preparation method. Firstly, preparing carbon foam through carbonization, and then generating MnO through hydrothermal reaction₂The composite material is used as a super capacitor electrode material, shows excellent electrochemical performance, is simple in preparation process, and has great application in the field of super capacitor energy storage.

Description

Pinecone-shaped MnO2Ball/foam carbon composite material and preparation method thereof

Technical Field

Background

Rapid development of global economy, depletion of fossil fuels, and aggravation of environmental pollution have prompted an increase in demand for environmentally friendly and efficient energy storage devices. Among the numerous energy storage devices, supercapacitors have been the focus of research due to their long cycle life, high power density and low cost.

Carbon foam is a lightweight porous material with a three-dimensional network morphology composed of amorphous carbon. The carbon foam as a promising electrode material of the super capacitor has the advantages of good chemical stability, low density, large conductivity, low cost and the like. Min and Chen et al studied the effect of Carbon foam precursors on pore structure, and polyurethane foams, as a raw material with low relative molecular mass, narrow relative molecular mass distribution, could form excellent pore structures for pitch-based Carbon foams (] Min ZHenhua, Cao Min, Zhang Shu, et al. Effect of curing on the pore structure of Carbon foams [ J ]. New Carbon Materials, 2007, 22(1): 57-59; Chen Chong, EllioKennel B, Stille Alfred H, et al. Carbon foam derived from gases curing [ J ]. Carbon, 2006, 44(8): 1535. 1543.). These studies establish a solid theoretical and experimental foundation for structural control of carbon foams. The melamine foam is a nano-scale three-dimensional network crosslinking structure soft thermosetting foam plastic prepared by alkaline melamine formaldehyde resin through special process microwave foaming, and the foam carbon is more suitable for being used as an electrode material because the melamine foam is composed of a three-dimensional network open-cell structure and has high open cell rate (the open cell rate is as high as 99.9%). However, the application of carbon foam in the field of supercapacitors is limited due to the low specific capacitance of carbon foam as an electrode material.

Disclosure of Invention

The invention aims to provide a carbon foam material which has stable 3D/3D composite appearance and can solve the problems of foam carbon monomer and MnO₂Pinecone-like MnO of low monomer conductivity and specific capacitance₂Ball/foam carbon composites. The obtained product is a nano composite material with stable structure and good electrochemical performance.

Pine cone MnO in the present invention₂The ball/foam carbon composite has a stable structure. Pine cone MnO₂Spherical/foam carbon composite material with uniform size and pine cone shape MnO₂The ball is formed by polymerizing smaller balls with the diameter of 10um and the diameter of the foam carbon of 4 um. As shown in fig. 1.

Pine cone MnO in the present invention₂Compared with a foam carbon monomer, the electrochemical performance of the ball/foam carbon composite material is remarkably improved. The specific capacity reached 185.6F/g at a scan rate of 20mV/s in a CV cycling test with a voltage ranging from-0.9 to-0.2V and a scan rate of 20 mV/s. As shown in fig. 2.

The technical scheme adopted for realizing the invention is as follows:

pine cone MnO₂The method has the characteristics of simple process, low cost and the like, and the obtained three-dimensional pinecone-shaped MnO is₂The spheres are uniformly dispersed on the three-dimensional foam carbon, and in a super capacitor, the electrochemical performance is excellent, and the preparation steps are as follows：

(1) Melamine (melamine) foam was cut into 1 cm. times.2 cm pieces and washed three times with deionized water and ethanol. After drying in a vacuum oven, putting the melamine (melamine) foam plastic block into a tube furnace, heating to a set temperature b and preserving heat at a certain heating rate a in a nitrogen atmosphere, then heating to a set temperature d at a certain heating rate c and preserving heat, naturally cooling, and collecting a sample to obtain the carbon foam.

The heating rate a is 5 ℃/min, the temperature b is set to be 400 ℃, and the heat preservation time is 2 h;

the heating rate c is 5 ℃/min, the set temperature d is 700 ℃, and the heat preservation time is 1 h;

the drying refers to drying for 24 hours in a vacuum drying oven at the temperature of 65 ℃.

(2) And (2) uniformly mixing a potassium permanganate solution in deionized water, adding the carbon foam prepared by carbonization in the step (1), continuously stirring and then carrying out ultrasonic treatment, adding a citric acid solution, continuously stirring for a period of time, then transferring the mixture into a reaction kettle, reacting at a certain temperature, naturally cooling to room temperature after the reaction is finished, washing and centrifuging the mixture three times by using deionized water and ethanol respectively, and drying the mixture in a vacuum drying oven. .

The volume ratio of the potassium permanganate solution to the deionized water to the citric acid solution is 1:5: 1.

The concentration of the potassium permanganate solution is 0.05M.

The concentration of the citric acid solution was 0.05M.

The continuous stirring time is 20min, and the ultrasonic time is 20 min.

The stirring was continued for 10 min.

The reaction temperature is 180 ℃, and the reaction time is 7 h.

The drying temperature is 60 ℃ and the drying time is 10 h.

Drawings

FIG. 1 shows a pine cone-shaped MnO₂Scanning electron micrographs of the spherical/carbon foam composite.

FIG. 2 shows pine cone MnO₂CV curves of the ball/foam carbon composite at different scan rates.

Detailed description of the preferred embodiments

The embodiment of the invention is a preparation method with simple process and relatively low cost, firstly, carbon foam is prepared by a high-temperature method carbonization method with different temperature gradients, and then pinecone-shaped MnO is synthesized by a hydrothermal method₂The ball/foam carbon composite material has 3D/3D composite morphology characteristics, and greatly improves the specific capacity and the cycling stability of the material.

The invention relates to pine cone MnO with excellent electrochemical performance₂The preparation method of the ball/foam carbon composite material comprises the following steps:

(1) melamine (melamine) foam was cut into 1 cm. times.2 cm pieces and washed three times with deionized water and ethanol. After drying in a vacuum oven, putting the melamine (melamine) foam plastic block into a tube furnace, heating to the set temperature of 400 ℃ at the heating rate of 5 ℃/min in the nitrogen atmosphere, preserving heat for 2h, then heating to the set temperature of 700 ℃ at the heating rate of 5 ℃/min, preserving heat for 1h, naturally cooling, and collecting the sample.

(2) Uniformly mixing 20ml of 0.05M potassium permanganate solution in 100ml of deionized water, adding the carbon foam prepared by carbonization in the step (1), continuously stirring for 20min and then performing ultrasonic treatment for 20min, adding 20ml of 0.05M citric acid solution, continuously stirring for 10min, then transferring the mixture into a reaction kettle, reacting for 7h at 180 ℃, naturally cooling to room temperature after the reaction is finished, washing and centrifuging for three times by using deionized water and ethanol respectively, and drying for 10h at 60 ℃ in a vacuum drying oven.

Claims

1. Pinecone-shaped MnO₂Ball/foam carbon composite material, its characterized in that: the composite material is made of pine cone-shaped MnO₂A spherical and three-dimensional foam carbon composite material, namely pine cone-shaped MnO₂Spherical/foam carbon composite material with uniform size and pine cone shape MnO₂The ball is polymerized by smaller balls, the diameter of the ball is 10um, the diameter of the foam carbon is 4um, the ball has the appearance characteristics of 3D/3D, and the ball is three-dimensional pinecone-shaped MnO₂The spheres were grown on three-dimensional carbon foam at CV cycles with test voltages ranging from-0.9V to-0.2V and scan rates of 20mV/s to 80mV/sPine cone MnO in Ring test₂The ball/foam carbon composite material shows excellent specific capacitance, the specific capacity reaches 185.6F/g at the scanning rate of 20mV/s, and the pine-shaped MnO is₂The preparation method of the ball/foam carbon composite material comprises the following steps:

uniformly mixing a potassium permanganate solution in deionized water, adding carbonized foam carbon, continuously stirring and then carrying out ultrasonic treatment, adding a citric acid solution, continuously stirring for a period of time, then transferring the mixture into a reaction kettle, reacting at a certain temperature, naturally cooling to room temperature after the reaction is finished, washing and centrifuging the mixture three times by using deionized water and ethanol respectively, and drying the mixture in a vacuum drying oven; the volume ratio of the potassium permanganate solution to the deionized water to the citric acid solution is 1:5: 1; the concentration of the potassium permanganate solution is 0.05M; the concentration of the citric acid solution is 0.05M; the continuous stirring time is 20min, and the ultrasonic time is 20 min; continuously stirring for 10 min; the reaction temperature is 180 ℃, the reaction time is 7h, the drying temperature is 60 ℃, and the drying time is 10 h.

2. The pinecone-shaped MnO2 sphere/carbon foam composite material of claim 1, wherein the carbon foam is prepared by the following method:

cutting melamine foam plastic into blocks, washing the blocks with deionized water and ethanol for three times, drying the blocks in a vacuum oven, putting the melamine foam plastic blocks into a tubular furnace, heating the blocks to a set temperature b at a certain heating rate a in a nitrogen atmosphere, preserving heat, then heating the blocks to a set temperature d at a certain heating rate c, preserving heat, naturally cooling, and collecting samples to obtain the carbon foam.

3. The pineal MnO2 sphere/carbon foam composite material of claim 2, wherein said blocks are 1cm x 2cm in size; the heating rate a is 5 ℃/min, the temperature b is set to be 400 ℃, and the heat preservation time is 2 h; the heating rate c is 5 ℃/min, the set temperature d is 700 ℃, and the heat preservation time is 1 h; the drying refers to drying for 24 hours in a vacuum drying oven at the temperature of 65 ℃.