Preparation of lignite-based activated carbon with high specific capacitance for electrochemical capacitors

2015 ◽  
Vol 08 (04) ◽  
pp. 1550031 ◽  
Author(s):  
Baolin Xing ◽  
Jianliang Cao ◽  
Yan Wang ◽  
Guiyun Yi ◽  
Chuanxiang Zhang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Electron Microscope ◽  
Specific Capacitance ◽  
Current Density ◽  
Electrode Materials ◽  
High Current Density ◽  
Electrochemical Capacitors ◽  
High Specific Capacitance ◽  
High Current ◽  
Charge Discharge

A lignite-based activated carbon (LAC) for electrochemical capacitors (ECs) was prepared from high moisture lignite by KOH activation, and the as-prepared sample was characterized by the N 2-sorption, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical performances of ECs with activated carbon as electrodes in 3 M KOH aqueous solution were evaluated by constant current charge-discharge and cyclic voltammetry. The LAC exhibits a well-developed surface area of 2581 m2/g, a relative wide pore size distribution of 0.5–10 nm. The ECs with LAC as electrode materials presents a high specific capacitance of 392 F/g at a low current density of 50 mA/g, and still remains 315 F/g even at a high current density of 5 A/g. The residual specific capacitance is as high as 92.9% after 2000 cycles. Compared with the commercial activated carbon (Maxsorb: Commercial product, Kansai, Japan), the LAC based electrode materials shows superior capacitive performance in terms of specific capacitance and charge–discharge performance at the high current density.

scholarly journals Effect of Prelithiation Process for Hard Carbon Negative Electrode on the Rate and Cycling Behaviors of Lithium-Ion Batteries

Batteries ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 71 ◽  
Author(s):  
Yusuke Abe ◽  
Tomoaki Saito ◽  
Seiji Kumagai
Keyword(s):  
Lithium Ion Batteries ◽  
Current Density ◽  
High Current Density ◽  
Negative Electrode ◽  
Lithium Ion ◽  
High Current ◽  
Hard Carbon ◽  
Li Ion ◽  
Charge Discharge ◽  
Ion Insertion

Two prelithiation processes (shallow Li-ion insertion, and thrice-repeated deep Li-ion insertion and extraction) were applied to the hard carbon (HC) negative electrode (NE) used in lithium-ion batteries (LIBs). LIB full-cells were assembled using Li(Ni0.5Co0.2Mn0.3)O2 positive electrodes (PEs) and the prelithiated HC NEs. The assembled full-cells were charged and discharged under a low current density, increasing current densities in a stepwise manner, and then constant under a high current density. The prelithiation process of shallow Li-ion insertion resulted in the high Coulombic efficiency (CE) of the full-cell at the initial charge-discharge cycles as well as in a superior rate capability. The prelithiation process of thrice-repeated Li-ion insertion and extraction attained an even higher CE and a high charge-discharge specific capacity under a low current density. However, both prelithiation processes decreased the capacity retention during charge-discharge cycling under a high current density, ascertaining a trade-off relationship between the increased CE and the cycling performance. Further elimination of the irreversible capacity of the HC NE was responsible for the higher utilization of both the PE and NE, attaining higher initial performances, but allowing the larger capacity to fade throughout charge-discharge cycling.

Hierarchical Dendritic Polypyrrole with High Specific Capacitance for High-performance Supercapacitor Electrode Materials

2017 ◽  
Vol 20 (4) ◽  
pp. 197-204
Author(s):  
Weiliang Chen ◽  
Shuhua Pang ◽  
Zheng Liu ◽  
Zhewei Yang ◽  
Xin Fan ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
Electrode Materials ◽  
High Specific Capacitance ◽  
Chemical Oxidation ◽  
Channel Structure ◽  
Supercapacitor Electrode ◽  
Infrared Spectrometer ◽  
A Current

Polypyrrole with hierarchical dendritic structures assembled with cauliflower-like structure of nanospheres, was synthesized by chemical oxidation polymerization. The structure of polyryrrole was characterized by Fourier transform infrared spectrometer and scanning electron microscopy. The electrochemical performance was performed on CHI660 electrochemical workstation. The results show that oxalic acid has a significant effect on morphology of PPy products. The hierarchical dendritic PPyOA(3) electrodes possess a large specific capacitance as high as 744 F/g at a current density of 0.2 A/g and could achieve a higher specific capacitance of 362 F/g even at a current density of 5.0 A/g. Moreover, the dendritic PPy products produce a large surface area on the electrode through the formation of the channel structure with their assembled cauliflower-like morphology, which facilitates the charge/electron transfer relative to the spherical PPy electrode. The spherical dendritic PPyOA(3) electrode has 58% retention of initial specific capacitance after 260 cycles. The as-prepared dendritic polypyrrole with high performance is a promsing electrode material for supercapacitor.

scholarly journals Hierarchical Porous Carbon Derived from Sichuan Pepper for High-Performance Symmetric Supercapacitor with Decent Rate Capability and Cycling Stability

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 553 ◽  
Author(s):  
Hengshuo Zhang ◽  
Wei Xiao ◽  
Wenjie Zhou ◽  
Shanyong Chen ◽  
Yanhua Zhang
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Rate Capability ◽  
Cycling Stability ◽  
Koh Activation ◽  
High Current ◽  
Symmetric Supercapacitor ◽  
Hierarchical Porous

Hierarchical micro-mesoporous carbon (denoted as HPC-2 in this study) was synthesized by pre-carbonization of biomass Sichuan pepper followed by KOH activation. It possessed well-developed porosity with the specific surface area of 1823.1 m2 g−1 and pore volume of 0.906 cm3 g−1, and exhibited impressive supercapacitive behaviors. For example, the largest specific capacitance of HPC-2 was tested to be ca. 171 F g−1 in a three-electrode setup with outstanding rate capability and stable electrochemical property, whose capacitance retention was near 100% after cycling at rather a high current density of 40 A g−1 for up to 10,000 cycles. Furthermore, a two-electrode symmetric supercapacitor cell of HPC-2//HPC-2 was constructed, which delivered the maximum specific capacitance and energy density of ca. 30 F g−1 and 4.2 Wh kg−1, respectively, had prominent rate performance and cycling stability with negligible capacitance decay after repetitive charge/discharge at a high current density of 10 A g−1 for over 10,000 cycles. Such electrochemical properties of HPC-2 in both three- and two-electrode systems are superior or comparable to those of a great number of porous biomass carbon reported previously, hence making it a promising candidate for the development of high-performance energy storage devices.

Low-Temperature Hydrothermal Synthesis and Electrochemical Properties of Birnessit-Type Manganese Dioxide Nanosheets

2013 ◽  
Vol 800 ◽  
pp. 393-397 ◽  
Author(s):  
De Yan ◽  
Ying Liu ◽  
Zhi Guo Wu ◽  
Ren Fu Zhuo ◽  
Jun Wang
Keyword(s):  
Low Temperature ◽  
Current Density ◽  
High Current Density ◽  
Hydrothermal Process ◽  
Rate Capability ◽  
High Specific Capacitance ◽  
High Current ◽  
Cycle Stability ◽  
Good Rate Capability ◽  
A Current

Birnessite MnO2 nanosheets were synthesized by self-limiting deposition of KMnO4 in a facile low-temperature hydrothermal process. The MnO2 electrode exhibits a high specific capacitance of 169 F g-1 at a current density of 0.1 A g-1, good rate capability with a capacitance of 96 F g-1 even at a high current density of 5 A g-1, as well as excellent cycle stability with capacitance retention of 94% at 1 A g-1 after 1,000 cycles.

MnO2 nanowires-decorated carbon fiber cloth as electrodes for aqueous asymmetric supercapacitor

2018 ◽  
Vol 11 (02) ◽  
pp. 1850034 ◽  
Author(s):  
Congcong Hong ◽  
Xing Wang ◽  
Houlin Yu ◽  
Huaping Wu ◽  
Jianshan Wang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Specific Capacitance ◽  
Current Density ◽  
Discharge Current ◽  
High Specific Capacitance ◽  
High Energy ◽  
Discharge Current Density ◽  
Carbon Fiber Cloth ◽  
A Charge ◽  
Charge Discharge

Manganese dioxide nanowires (MnO2 NWs) anchored on carbon fiber cloth (CFC) were fabricated through a simple hydrothermal reaction and used as integrated electrodes for supercapacitor. The morphology-dependent electrochemical performance of MnO2 NWs was confirmed, yielding good capacitance performance with a high specific capacitance of 3.88[Formula: see text][Formula: see text] at a charge–discharge current density of 5[Formula: see text][Formula: see text] and excellent stability of 91.5% capacitance retention after 3000 cycles. Moreover, the composite electrodes were used to fabricate supercapacitors, which showed a high specific capacitance of 194[Formula: see text][Formula: see text] at a charge–discharge current density of 2[Formula: see text][Formula: see text] and high energy density of 0.108[Formula: see text][Formula: see text] at power density of 2[Formula: see text][Formula: see text], foreboding its potential application for high-performance supercapacitor.

MnOx/Ni(OH)2 Nanocomposite Materials for High-Performance Electrochemical Capacitor Application

2012 ◽  
Vol 20 ◽  
pp. 53-60 ◽  
Author(s):  
Zan Wang ◽  
Xin Wang ◽  
Yun Xiao Zhao ◽  
Cui Mei Zhao ◽  
Wei Tao Zheng
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
High Specific Capacitance ◽  
Discharge Process ◽  
Porous Network ◽  
X Ray ◽  
Capacitance Performance ◽  
Charge Discharge

Nanostructured MnOx/Ni (OH)2 composites have been electrodeposited on Ni foam for synthesis of a binder-free electrode for electrochemical capacitors with high specific capacitance and stable electrochemical properties. The microstructure, morphology and chemical composition were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Cyclic voltammetry and galvanostatic charge/discharge measurements were applied to investigate the electrochemical capacitance of the electrode active materials. The results indicated that MnOx acted as a template for growth of Ni (OH)2 with an inter-connected 3D porous network nanostructure. A maximum capacitance value of 2334 F/g at current density of 5 A/g in 1 M KOH electrolyte was achieved, much higher than that of pure Ni (OH)2 and MnOx (992 and 179 F/g, respectively). Moreover, in the charge/discharge process at even larger current density of 20 A/g, the electrode could maintain 82.8 % of the initial specific capacitance after 500 cycles, higher than that of pure Ni (OH)2 (only 46.6% remains). The enhanced capacitance performance was attributed to the synergic effect between the respective single oxides.

scholarly journals Iron Disulfide Synthesis for Thermal Batteries Applications

2020 ◽  
pp. 50-53 ◽  
Author(s):  
Gabriel Evangelista Medeiros ◽  
Francisco José Moura ◽  
Rodrigo Fernandes Magalhães de Souza
Keyword(s):  
Current Density ◽  
High Current Density ◽  
High Dispersion ◽  
High Current ◽  
Power Sources ◽  
Iron Disulfide ◽  
Thermal Batteries ◽  
Single Discharge ◽  
Emergency Systems ◽  
Charge Discharge

The necessity for ever more efficient and compact power sources drives the development of more durable and more power-intensive sources. Electrochemical sources include primary batteries that support a single discharge cycle and secondary batteries that support a defined number of charge-discharge cycles. Such sources should be suitable for the intended application, such as emergency systems, military and aerospace apparatus, where they must have long shelf life, high current density and reliability. Thermal batteries work with LiCl-KCl eutectic electrolyte anodes and FeS2 cathodes. A pyrometallurgical synthesis route was studied for roasting reaction between Fe2O3 and vaporized sulfur to obtain FeS2. The results obtained showed a conversion close to 90% and a high dispersion of agglomerates sizes, which disaggregated generate particles suitable for cathode manufacturing.

Sign in / Sign up

Export Citation Format

Share Document