One-pot synthesis of thin Co(OH)2 nanosheets on graphene and their high activity as a capacitor electrode

RSC Advances ◽  
2014 ◽  
Vol 4 (93) ◽  
pp. 51619-51623 ◽  
Author(s):  
Gyoung Hwa Jeong ◽  
Hae-Min Lee ◽  
Heewoong Lee ◽  
Chang-Koo Kim ◽  
Yuanzhe Piao ◽  
...  

We synthesized Co(OH)2/graphene composites from graphite without a graphene oxide (GO) step. The Co(OH)2/graphene composite exhibited a specific capacitance of 960 F g−1 at a current density of 10 A g−1.

2019 ◽  
Vol 31 (9-10) ◽  
pp. 1238-1247 ◽  
Author(s):  
Shanxin Xiong ◽  
Yuancheng Wang ◽  
Jia Chu ◽  
Xiaoqin Wang ◽  
Runlan Zhang ◽  
...  

In this article, polyaniline nanofibers/reduced graphene oxide (PANI-NFs/rGO) nanocomposites were prepared by a one-pot hydrothermal method. Under the condition of high temperature and high pressure, graphene oxide (GO) was reduced to rGO and aniline was in-situ polymerized to form PANI-NFs using ammonium persulfate as oxidant. The morphologies and structures of PANI-NFs/rGO nanocomposites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and Raman analysis. The results show that PANI-NFs uniformly grow on the surfaces of rGO sheets, which can act as spacers to prevent the aggregation of rGO. Combining with FTIR and Raman analysis, it can be concluded that PANI-NFs/rGO nanocomposites are successfully prepared. The electrochemical performances of PANI-NFs/rGO nanocomposites were tested by cyclic voltammetry and galvanostatic charge–discharge. The PANI-NFs/rGO nanocomposites exhibit superior electrochemical performances compared to the PANI-NFs. With 10 wt% of GO loaded, the PANI-NFs/rGO nanocomposite exhibits highest specific capacitance of 942 F g−1 at a current density of 1 A g−1. The PANI-NFs/rGO nanocomposites also demonstrate good rate capacity and high cycling stability under the high discharging current density (10 A g−1), the specific capacitance can still reach to 680 F g−1. After 1000 charge–discharge cycling at a current density of 5 A g−1, 78% of specific capacitance can be retained. The enhanced capacitive performances can be attributed to the facile electron conduction pathway brought by the even distribution of highly conductive rGO nanosheets.


2013 ◽  
Vol 785-786 ◽  
pp. 783-786 ◽  
Author(s):  
Hong Juan Wang ◽  
Dong Zhou ◽  
Feng Peng ◽  
Hao Yu

Graphene with different reduction degrees was prepared by fast thermally reduction of exfoliated graphite oxide (GO) at 200-700 °C. Structure and the electrochemical capacitive performance were characterized and measured. The results show that different thermal reduction temperatures can obtain reduced graphene oxide (rGO) with different reduction degrees and influence the electrochemical capacitive performance. The rGO-400 by thermal treat at 400 °C exhibits a significantly high specific capacitance of 407 F g-1 in 6.0 M KOH electrolyte at a current density of 0.4 A g-1 and outstanding cyclic stability with 96.1% of its origin specific capacitance maintained after 2000 cycles at the current density of 10 A g-1 in GCD test.


2013 ◽  
Vol 106 ◽  
pp. 171-174 ◽  
Author(s):  
Yichao Gong ◽  
Xiaopeng Meng ◽  
Changwu Zou ◽  
Yadong Yao ◽  
Weidong Fu ◽  
...  

2021 ◽  
Vol 5 (5) ◽  
pp. 129
Author(s):  
Yapeng Wang ◽  
Yanxiang Wang ◽  
Chengjuan Wang ◽  
Yongbo Wang

As one of the most outstanding high-efficiency and environmentally friendly energy storage devices, the supercapacitor has received extensive attention across the world. As a member of transition metal oxides widely used in electrode materials, manganese dioxide (MnO2) has a huge development potential due to its excellent theoretical capacitance value and large electrochemical window. In this paper, MnO2 was prepared at different temperatures by a liquid phase precipitation method, and polyaniline/manganese dioxide (PANI/MnO2) composite materials were further prepared in a MnO2 suspension. MnO2 and PANI/MnO2 synthesized at a temperature of 40 °C exhibit the best electrochemical performance. The specific capacitance of the sample MnO2-40 is 254.9 F/g at a scanning speed of 5 mV/s and the specific capacitance is 241.6 F/g at a current density of 1 A/g. The specific capacitance value of the sample PANI/MnO2-40 is 323.7 F/g at a scanning speed of 5 mV/s, and the specific capacitance is 291.7 F/g at a current density of 1 A/g, and both of them are higher than the specific capacitance value of MnO2. This is because the δ-MnO2 synthesized at 40 °C has a layered structure, which has a large specific surface area and can accommodate enough electrolyte ions to participate the electrochemical reaction, thus providing sufficient specific capacitance.


2012 ◽  
Vol 18 (45) ◽  
pp. 14359-14366 ◽  
Author(s):  
Xinman Tu ◽  
Shenglian Luo ◽  
Guixiang Chen ◽  
Jinghong Li

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