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Carboxyl-Assisted Synthesis of Nitrogen-Doped Graphene Sheets for Supercapacitor Applications.

Xie B, Chen Y, Yu M, Shen X, Lei H, Xie T, Zhang Y, Wu Y - Nanoscale Res Lett (2015)

Bottom Line: The structure of the N-doped graphene with different surface functional groups was characterized by Raman spectroscopy.The research result indicates that the carboxylation of GO is the key factor to obtain pyridinic and pyridone N types during the N atom doping process.Compared to general N-doped graphene, the electrochemical test shows that specific capacitance of the GO-OOH-N sample reaches up to 217 F/g at a discharge current density 1 A/g and stable cycling performance (keep 88.8 % specific capacitance after 500 cycles at the same discharge current density) when applied to the supercapacitor electrode materials.

View Article: PubMed Central - PubMed

Affiliation: Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 388 Lumo RD, Wuhan, 430074, China, 391856294@qq.com.

ABSTRACT
The high ratio of pyridinic and pyridone N-doped graphene sheets have been synthesized by functionalizing graphene oxide (GO) with different oxygen groups on its surface. The typical N-doped graphene was determined to be ~3-5 layers by transmission electron microscopy (TEM) and atomic force microscopy (AFM), and the nitrogen content was measured as 6.8-8 at. % by X-ray photoelectron spectroscopy (XPS). The structure of the N-doped graphene with different surface functional groups was characterized by Raman spectroscopy. The research result indicates that the carboxylation of GO is the key factor to obtain pyridinic and pyridone N types during the N atom doping process. Compared to general N-doped graphene, the electrochemical test shows that specific capacitance of the GO-OOH-N sample reaches up to 217 F/g at a discharge current density 1 A/g and stable cycling performance (keep 88.8 % specific capacitance after 500 cycles at the same discharge current density) when applied to the supercapacitor electrode materials.

No MeSH data available.


a CV curves of samples at 20 mV/s. b CV curves of GO-OOH-N at different scan rates. c Specific capacitance of samples at different current density. d Galvanostatic charge/discharge (GCD) curves of GO-OOH-N. e EIS spectrum of samples. f Cycling performance of GO-N and GO-OOH-N
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Fig6: a CV curves of samples at 20 mV/s. b CV curves of GO-OOH-N at different scan rates. c Specific capacitance of samples at different current density. d Galvanostatic charge/discharge (GCD) curves of GO-OOH-N. e EIS spectrum of samples. f Cycling performance of GO-N and GO-OOH-N

Mentions: The supercapacitor performances of GO-N, GO-N-180, and GO-OOH-N were comparatively investigated in a 6 M KOH solution using a three-electrode configuration. Figure 6a shows the cyclic voltammetry (CV) curves of different samples with the scan rate at 20 mV/s. They all show a good rectangle shape with well-broaden peaks, indicating a capacitive behavior of electrical double-layer capacitance (EDLC) and pseudocapacitance. It is clear that the maximum specific capacitance of GO-OOH-N possesses the largest curves area and the most pronounced pseudocapacitive peaks because of the high content (proportion) of N-5/N-6 and carboxyl groups, which is closely linked with Faradic reaction [26]. Compared to GO-N, the curve area of GO-N-180 electrode decreased apparently due to its higher defect degree. With the scan rate increased, the pseudocapacitive feature of GO-OOH-N remained at CV curves all along from 5 to 50 mV/s (Fig. 6b), indicating a good wettability and easy access of ions to the GO-OOH-N electrode surface. However, the peaks arising from the redox reactions of surface functionalities are slighted reduced at higher scan rates, due to the relatively low charge/discharge kinetics compared to EDLC.Fig. 6


Carboxyl-Assisted Synthesis of Nitrogen-Doped Graphene Sheets for Supercapacitor Applications.

Xie B, Chen Y, Yu M, Shen X, Lei H, Xie T, Zhang Y, Wu Y - Nanoscale Res Lett (2015)

a CV curves of samples at 20 mV/s. b CV curves of GO-OOH-N at different scan rates. c Specific capacitance of samples at different current density. d Galvanostatic charge/discharge (GCD) curves of GO-OOH-N. e EIS spectrum of samples. f Cycling performance of GO-N and GO-OOH-N
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Fig6: a CV curves of samples at 20 mV/s. b CV curves of GO-OOH-N at different scan rates. c Specific capacitance of samples at different current density. d Galvanostatic charge/discharge (GCD) curves of GO-OOH-N. e EIS spectrum of samples. f Cycling performance of GO-N and GO-OOH-N
Mentions: The supercapacitor performances of GO-N, GO-N-180, and GO-OOH-N were comparatively investigated in a 6 M KOH solution using a three-electrode configuration. Figure 6a shows the cyclic voltammetry (CV) curves of different samples with the scan rate at 20 mV/s. They all show a good rectangle shape with well-broaden peaks, indicating a capacitive behavior of electrical double-layer capacitance (EDLC) and pseudocapacitance. It is clear that the maximum specific capacitance of GO-OOH-N possesses the largest curves area and the most pronounced pseudocapacitive peaks because of the high content (proportion) of N-5/N-6 and carboxyl groups, which is closely linked with Faradic reaction [26]. Compared to GO-N, the curve area of GO-N-180 electrode decreased apparently due to its higher defect degree. With the scan rate increased, the pseudocapacitive feature of GO-OOH-N remained at CV curves all along from 5 to 50 mV/s (Fig. 6b), indicating a good wettability and easy access of ions to the GO-OOH-N electrode surface. However, the peaks arising from the redox reactions of surface functionalities are slighted reduced at higher scan rates, due to the relatively low charge/discharge kinetics compared to EDLC.Fig. 6

Bottom Line: The structure of the N-doped graphene with different surface functional groups was characterized by Raman spectroscopy.The research result indicates that the carboxylation of GO is the key factor to obtain pyridinic and pyridone N types during the N atom doping process.Compared to general N-doped graphene, the electrochemical test shows that specific capacitance of the GO-OOH-N sample reaches up to 217 F/g at a discharge current density 1 A/g and stable cycling performance (keep 88.8 % specific capacitance after 500 cycles at the same discharge current density) when applied to the supercapacitor electrode materials.

View Article: PubMed Central - PubMed

Affiliation: Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 388 Lumo RD, Wuhan, 430074, China, 391856294@qq.com.

ABSTRACT
The high ratio of pyridinic and pyridone N-doped graphene sheets have been synthesized by functionalizing graphene oxide (GO) with different oxygen groups on its surface. The typical N-doped graphene was determined to be ~3-5 layers by transmission electron microscopy (TEM) and atomic force microscopy (AFM), and the nitrogen content was measured as 6.8-8 at. % by X-ray photoelectron spectroscopy (XPS). The structure of the N-doped graphene with different surface functional groups was characterized by Raman spectroscopy. The research result indicates that the carboxylation of GO is the key factor to obtain pyridinic and pyridone N types during the N atom doping process. Compared to general N-doped graphene, the electrochemical test shows that specific capacitance of the GO-OOH-N sample reaches up to 217 F/g at a discharge current density 1 A/g and stable cycling performance (keep 88.8 % specific capacitance after 500 cycles at the same discharge current density) when applied to the supercapacitor electrode materials.

No MeSH data available.