Surface Modification of Carbon Electrodes for Supercapacitor Using Ammonia Water

2011 ◽  
Vol 396-398 ◽  
pp. 1265-1268 ◽  
Author(s):  
Ren Qing Wang ◽  
Mei Gen Deng
Keyword(s):  
Surface Modification ◽  
Activated Carbon ◽  
Specific Capacitance ◽  
Carbon Materials ◽  
Solution Concentration ◽  
Ammonia Solution ◽  
Constant Current ◽  
Power Performance ◽  
Ammonia Water ◽  
Constant Current Charge

In this work, activated carbon was modified by ammonia water. Cyclic voltammetry and constant current charge-discharge were used to characterize the electrochemical performance of the samples in 1.0 mol/L Et4NBF4-PC solution. As a result, optimal conditions for surface modification of activated carbon have been examined as an ammonia solution concentration of 5wt.%. Specific capacitance can be improved significantly by surface modification of carbon materials. The specific capacitance of the carbon modified with 5.0wt.% ammonia water reached 114 F/g at a current density of 3.0 mA/cm2, which is 14% higher than that of untreated sample. In addition, the modified carbon materials possess excellent power performance.

Surface Oxidation Modification and Performance of Activated Carbon Electrode Material

2011 ◽  
Vol 347-353 ◽  
pp. 3456-3458
Author(s):  
Ren Qing Wang ◽  
Mei Gen Deng
Keyword(s):  
Activated Carbon ◽  
Specific Capacitance ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Surface Oxidation ◽  
Constant Current ◽  
Carbon Electrode ◽  
Constant Current Charge ◽  
And Performance ◽  
Double Layer Capacitors

Superscript text Commercial activated carbon was modified by surface treatment using nitric acid, The modified carbons were characterized by X-ray photoelectron spectroscopy (XPS).The resultant carbon electrode-based electric double-layer capacitors (EDLCs)were assembled with 1 mol/L （NH4）2SO4 as the electrolyte. The influence of introduced functional groups, such as hydroxyl and carbonyl, on the performance of EDLCs was studied by Constant current charge-discharge. These functional groups significantly improved the wettability of AC. As a result, the specific capacitance of the carbon modified with 40wt.%HNO3 achieved a specific capacitance of 223.45 F/g at a current density of 5mA/cm2, which is 100.9% higher than that of original AC.

Preparation and Electrochemical Characterization of Mn/Pb Composite Oxides for Supercapacitors

2007 ◽  
Vol 336-338 ◽  
pp. 470-473
Author(s):  
Zhian Zhang ◽  
Yan Qing Lai ◽  
Jie Li ◽  
Ye Xiang Liu
Keyword(s):  
Specific Capacitance ◽  
Electrochemical Characterizations ◽  
Amorphous Structure ◽  
Electrode System ◽  
Constant Current ◽  
Manganese Acetate ◽  
Composite Oxides ◽  
Constant Current Charge ◽  
Nano Size

Mn/Pb composite oxides were prepared by solid-state reaction by KMnO4 with manganese acetate and lead acetate at low temperature. The products were characterized by XRD and TEM. The results show that the composite oxides are nano-size and amorphous structure. Electrochemical characterizations were performed by cyclic voltammetry (CV) and constant current charge-discharge in a three-electrode system. The potential windows of Mn/Pb composite oxides electrode are increased. With increasing the ratio of Pb, the specific capacitance goes through a maximum at 20% mol Pb. The specific capacitance of pure MnO2 is 158 F/g and is improved to 180 F/g for the Mn0.8Pb0.2Ox composite oxide by constant current discharge.

A Facile Synthesis of NiFe2O4 with High Specific Capacitance as Supercapacitor Electrode Material

2018 ◽  
Vol 281 ◽  
pp. 854-858
Author(s):  
Xi Cheng Gao ◽  
Jian Qiang Bi ◽  
Wei Li Wang ◽  
Guo Xun Sun ◽  
Xu Xia Hao ◽  
...  
Keyword(s):  
Particle Size ◽  
Specific Capacitance ◽  
Electrochemical Property ◽  
Electrode Materials ◽  
High Specific Capacitance ◽  
Constant Current ◽  
X Ray Diffraction ◽  
Supercapacitor Electrode ◽  
Constant Current Charge ◽  
Supercapacitor Electrode Materials

NiFe2O4 powders were synthesized by a facile hydrothermal method at 180°C followed by a thermal treatment at 300°C. The phase composition and morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the NiFe2O4 powders were well-crystallized, and they possessed a particle size in the range of 50-100 nm. The electrochemical property was characterized via cyclic voltammetry (CV) and constant current charge-discharge method. Encouragingly, the NiFe2O4 powders had an excellent electrochemical property, whose specific capacitance reached 266.84 F/g at the electric current density of 1 A/g due to the small particle size. Compared with other Fe-based metal compound oxides, NiFe2O4 has a better electrochemical performance, which can be widely used in the supercapacitor electrode materials.

Increasing Energy Storage in Activated Carbon based Electrical Double Layer Capacitors through Plasma Processing

2015 ◽  
Vol 1773 ◽  
pp. 15-20 ◽  
Author(s):  
Marcelis L. Muriel ◽  
Rajaram Narayanan ◽  
Prabhakar R. Bandaru
Keyword(s):  
Activated Carbon ◽  
Electrochemical Techniques ◽  
Plasma Processing ◽  
Argon Plasma ◽  
Fold Increase ◽  
Electrical Impedance Spectroscopy ◽  
Constant Current ◽  
Constant Current Charge ◽  
Charged Defects ◽  
Double Layer Capacitors

ABSTRACTWe present a methodology to enhance the electrical capacitance of activated carbon (AC) electrodes based on the introduction of electrically charged defects through argon plasma processing. Extensive characterization using electrochemical techniques incorporating cyclic voltammetry, constant current charge/discharge, and electrical impedance spectroscopy indicated a close to seven-fold increase in capacitance with respect to untreated AC electrodes, not subject to plasma processing.

Ruthenium Oxide/Activated Carbon Composites for Electrochemical Capacitors

2011 ◽  
Vol 347-353 ◽  
pp. 3370-3374
Author(s):  
Ming Dong Zheng ◽  
Ru Chun Li ◽  
Xiao Jun He ◽  
Xian Ping Dong ◽  
Ping Hua Ling ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Ruthenium Oxide ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Micropore Volume ◽  
Constant Current ◽  
Composite Electrodes ◽  
Hno3 Solution ◽  
Constant Current Charge ◽  
Charge Discharge

Activated carbon (AC) was prepared from lignite by microwave heating ZnCl2. The pore structure parameters of AC are characterized by nitrogen adsorption technique. The AC and ruthenium oxide/AC composite are characterized by thermogravimetric analysis and transmission electron microscope. Electrochemical properties of ACs and ruthenium oxide/AC composite electrodes were investigated by cyclic voltammetry and constant current charge–discharge after AC was pre−oxidized by HNO3 solution. The results show that the specific surface area and total pore volume of AC from lignite reaches 1310 m2 g−1 and 0.80 cm3 g−1, respectively. The micropore volume of AC from lignite totals only 12.5%. AC and ruthenium oxide/AC composite electrodes with 5wt.% ruthenium oxide loading show high cycle stability. Compared to pristine AC electrode, specific capacitance of ruthenium/AC composite electrode and energy density of ruthenium/AC capacitor after 100 charge−discharge cycles increases 40.8% and 39.1%, respectively.

Preparation and Electrochemical Properties of CeO2/rGO Composite Material

2020 ◽  
Vol 842 ◽  
pp. 76-82
Author(s):  
Jin Hui Xu ◽  
Lin Wu ◽  
Ying Liu ◽  
Jia Ming Liu ◽  
Sha Sha Shu ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Specific Capacitance ◽  
Redox Reactions ◽  
Active Sites ◽  
Composite Electrode ◽  
Electrochemical Stability ◽  
Cycle Performance ◽  
Constant Current ◽  
Constant Current Charge ◽  
Structure And Microstructure

The CeO2/rGO composites were prepared by hydrothermal method. The microscopic phase structure and microstructure of the samples were characterized by SEM, XRD and FTIR. The cyclic voltammetry (CV) and constant current charge and discharge tests were used to study the electrochemical stability and cycle ability of the CeO2/rGO composite electrode. The results show that the incorporation of graphene effectively increases the reversibility of CeO2 as an electrode material. The special structure of graphene provides a continuous network and more active sites for redox reactions. In the 6mol/L KOH electrolyte, the specific capacitance of CeO2/rGO composite reached 114F·g-1 when the current density was 0.5A/g. After 1000 cycles, the specific capacitance only decreased by 12.66%, which proves that this material has good cycle performance.

scholarly journals Surface Modification of Activated Carbon for Enhancement of Nickel(II) Adsorption

2008 ◽  
Vol 5 (4) ◽  
pp. 814-819 ◽  
Author(s):  
A. Edwin Vasu
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Modification ◽  
Activated Carbon ◽  
Nitric Acid ◽  
Aqueous Solutions ◽  
Ir Spectra ◽  
Carbon Materials ◽  
Batch Mode ◽  
Ammonium Persulphate ◽  
Coconut Shells

A carbon prepared from coconut shells by simple carbonization was oxidized with different oxidizing agents, namely, hydrogen peroxide, ammonium persulphate and nitric acid. The surfaces of the unoxidized and oxidized carbons were characterized by Boehm and potentiometric titrations and IR spectra. The carbon materials prepared were tested for their ability to remove Ni(II) ions from aqueous solutions by batch mode adsorption experiments. Oxidations increased the surface acidic groups on the carbon which resulted in increased affinity of the carbon towards Ni(II).

Effect of Ultrasonic Disperse on the Properties of Carbon Nanotubes Supercapacitors

2010 ◽  
Vol 148-149 ◽  
pp. 1417-1420 ◽  
Author(s):  
Xin Sheng Yuan ◽  
Hai Yan Zhang ◽  
Yi Ming Chen
Keyword(s):  
Carbon Nanotubes ◽  
Specific Capacitance ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Constant Current ◽  
Ultrasonic Dispersion ◽  
Supercapacitor Electrode ◽  
Constant Current Charge ◽  
Lani5 Alloy ◽  
Charge Discharge

Carbon nanotubes (CNTs) of different diameter were synthesized by chemical vapor deposition using LaNi5 alloy of micrometer magnitude as catalyst. High-power ultrasonic grinder was employed to disperse CNTs for various time. CNTs with different dispersion levels were obtained and their impacts on the performance of CNTs supercapacitor electrode were researched as well. Constant current charge-discharge, Cycle Votammetry was employed to study the supercapacitors properties of carbon nanotubes. And the results showed that the specific capacitance of CNTs electrode without ultrasonic was 95.88F/g. However CNTs electrode has preferable electrochemistry properties with 16 hours ultrasonic dispersion, CNTs diameter about 30-50nm and well dispersibility: the specific capacitance had enhanced 69.9%, as high as 162.88F/g.

Study on the Application of N,N′-1-Ethyl-4-Butyl, Triethylene and Diamine Hexafluorophosphate in Supercapacitors

2012 ◽  
Vol 535-537 ◽  
pp. 2061-2064
Author(s):  
Ke Di Cai ◽  
Wei Fang Mu ◽  
Jun Yi Mu ◽  
Zhen Xing Jin
Keyword(s):  
Activated Carbon ◽  
Specific Capacitance ◽  
Active Carbon ◽  
Ac Impedance ◽  
Constant Current ◽  
Capacitance Characteristics ◽  
Constant Current Charging

An electrolyte, N,N′-1-ethyl-4-butyl, triethylene diamine hexafluorophosphate dissolved in glutaronitrile, was developed and investigated in a symmetrical supercapacitor using activated carbon as electrodes (active carbon/active carbon). The electrochemical erformance of the supercapacitor was examined using ac impedance and constant current charging/discharging tests. According to the results, its singleanode specific capacitance could reach 324.7 Fg−1. The supercapacitor also has better capacitance characteristics.

Direct Preparation of Activated Carbon from Coal and its Electrochemical Properties for Electric Double Layer Capacitor

2011 ◽  
Vol 197-198 ◽  
pp. 1253-1257
Author(s):  
Ming Dong Zheng ◽  
Xiao Yong Zhang ◽  
Ru Chun Li ◽  
Ming Bo Wu ◽  
Ye Jing Geng ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Electrochemical Properties ◽  
Pore Volume ◽  
Total Pore Volume ◽  
Micropore Volume ◽  
Constant Current ◽  
Coal Rank ◽  
Double Layer Capacitor ◽  
Direct Preparation ◽  
Constant Current Charge

Direct preparation of activated carbon (AC) from coal was reported by microwave heating with potassium hydroxide as activation agent. Electrochemical properties of AC electrodes were investigated by cyclic voltammetry, constant current charge–discharge. The results show that functional groups on AC include –C=O, –O–H and –C–O. The micropore volume of AC from different coal totals 48.5–95.6%. The total pore volume of AC from different coal passes through a maximum with the decrease of volatile mater content in coal. The specific surface area and total pore volume of AC from Qing ting coal reach 1874 m2 g-1 and 1.00 cm3 g-1, respectively. The specific capacitance and energy density of AC from higher coal rank is usually bigger than that of AC from lower coal rank.

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