scholarly journals From flax fibers to activated carbon electrodes: The role of fiber refining

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 1296-1310
Author(s):  
Hongwei Li ◽  
Yucheng Feng ◽  
Lvqiao Tang ◽  
Fei Yang
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
Electrode Material ◽  
High Current Density ◽  
High Specific Surface Area ◽  
Pulp Fibers ◽  
Flax Fibers ◽  
Synergistic Activation ◽  
Porous Microstructure

Flax-based activated porous carbon materials (APCs) were prepared via KOH and urea synergistic activation in the carbonization process using flax pulp as a biocompatible and eco-friendly biomass precursor. A refining process was used to pretreat the flax pulp fibers, which has been known to improve and optimize the performance of APCs. The morphological and physicochemical structures of APCs were investigated, and the results showed that APCs exhibited high specific surface area and porous microstructure. Furthermore, APCs were rationally designed as a sustainable electrode material. The APC prepared by 60 °SR (Shopper-Riegler beating degree) flax pulp, named APC-60, exhibited the highest specific capacitance of 265.8 F/g at a current density of 0.5 A/g. The specific capacitance retention at 59% remained for the APC-60 electrodes at a high current density of 10 A/g. These results suggested that the flax-based APCs could be a promising carbon-based electrode material for sustainable electrochemical energy storage.

Uncovering the role of Ag in layer-alternating Ni3S2/Ag/Ni3S2 as an electrocatalyst with enhanced OER performance

2020 ◽  
Vol 7 (19) ◽  
pp. 3627-3635 ◽  
Author(s):  
Rui Guo ◽  
Yan He ◽  
Renchao Wang ◽  
Junhua You ◽  
Hongji Lin ◽  
...  
Keyword(s):  
Water Splitting ◽  
Current Density ◽  
High Current Density ◽  
High Current

It is increasingly important to develop an efficient OER catalyst that can provide high current density at low overpotentials to improve water splitting efficiency.

scholarly journals Morphology and Hardness of Electrochemically-Codeposited Ti-Dispersed Ni-Matrix Composite Coatings/ Morfologia I Twardość Elektrochemicznie Współosadzonych Powłok Kompozytowych Ni-Ti

2014 ◽  
Vol 59 (4) ◽  
pp. 1287-1292 ◽  
Author(s):  
S. Srikomol ◽  
P. Janetaisong ◽  
Y. Boonyongmaneerat ◽  
R. Techapiesancharoenkij
Keyword(s):  
Matrix Composite ◽  
Current Density ◽  
High Current Density ◽  
Composite Coatings ◽  
Initial Increase ◽  
Particle Loading ◽  
Plating Bath ◽  
Matrix Deformation ◽  
Ti Particles

Abstract The effects of current density and Ti particle loading in a plating bath on the morphology and hardness of Ni-Ti composite coatings via an electrochemical-codeposition process were investigated. The Ti-reinforced Ni-matrix composite coatings were codeposited on copper substrates using a Ni-ion electrolytic solution stably suspended with -45 micron Ti particles. Within the current studied range, the coatings’ Ti contents are in the range between 46 and 62 at.%. The morphology appeared to vary with current density. Structures of the Ni-Ti composite coatings produced under low current density conditions revealed denser structures, which is in contrast to the more porous structures noted in the coatings produced under high current density. An initial increase of current density from 100 to 150 mA/cm2 also tends to raise Ti coating content. The reinforcement of Ti particles in the coatings also increased their hardness, which is attributed to the possible role of the embedded Ti particles in hindering matrix deformation. The effect of Ti loading on the coating’s Ti contents was not significant under conditions used in the present study

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.

7,7,8,8-Tetracyanoquinodimethane-assisted one-step electrochemical exfoliation of graphite and its performance as an electrode material

Nanoscale ◽  
2014 ◽  
Vol 6 (9) ◽  
pp. 4864-4873 ◽  
Author(s):  
Partha Khanra ◽  
Chang-No Lee ◽  
Tapas Kuila ◽  
Nam Hoon Kim ◽  
Min Jun Park ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
Electrode Material ◽  
Functionalized Graphene ◽  
Electrochemical Exfoliation ◽  
Water Dispersible ◽  
Surface Modifiers ◽  
One Step ◽  
Modified Graphene ◽  
A Current

Water-dispersible functionalized graphene via one-step electrochemical exfoliation of graphite was prepared using 7,7,8,8-tetracyanoquinodimethane (TCNQ) anions as surface modifiers and electrolytes. The specific capacitance value of TCNQ-modified graphene measured with electrolytes (1 M KOH) was 324 F g−1 at a current density of 1 A g−1.

scholarly journals Sodium Dodecylbenzene Sulfonate Assisted Electrodeposition of MnO2@C Electrode for High Performance Supercapacitor

2021 ◽  
Author(s):  
Yihan Shi ◽  
Ming Zhang ◽  
Junshan Zhao ◽  
Liu Zhang ◽  
Xumei Cui ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Nickel Foam ◽  
Chemical Vapor ◽  
Precursor Solution ◽  
Sodium Dodecylbenzene Sulfonate ◽  
Dodecylbenzene Sulfonate

Abstract In this work, MnO2&SDBS electrodes with nano-honeycomb morphology were prepared by ultrasound-assisted electrochemical deposition using sodium dodecylbenzene sulfonate (SDBS) as a surfactant agent. The effect and mechanism of SDBS on the morphology of MnO2 nanomaterials during the preparation of MnO2 by electrochemical anodic oxidation was systematically investigated by varying the content of SDBS in the precursor solution. When the SDBS concentration is 2 g\bulletL-1, the resulting electrode has the best electrochemical performance, and the specific capacitance is up to 407 F\bulletg-1 at the current density of 1000 mAg-1. To further enhance its performance, a carbon coating layer was deposited on the surface of the electrode using a method similar to chemical vapor deposition. Finally, the MnO2&SDBS@C electrode with a three-dimensional net-to-film composite structure with a high specific surface area, hierarchical structure and interconnect with nickel foam supports were obtained. The electrode has excellent electrochemical performance, and the specific capacitance is still up to 289 Fg-1 at a high current density of 5000 mAg-1. Furthermore, the specific capacitance of the electrode was maintained at 76.7% after 5000 cycles of charging and discharging at a current density of 2000 mAg−1.

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.

scholarly journals Electrochemical Performances Investigation of New Carbon-Coated Nickel Sulfides as Electrode Material for Supercapacitors

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3509 ◽  
Author(s):  
Xinyu Lei ◽  
Mu Li ◽  
Min Lu ◽  
Xiaohui Guan
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
Electrode Material ◽  
Rate Capability ◽  
Nitrogen Atmosphere ◽  
Electrochemical Performances ◽  
Discharge Process ◽  
Carbon Coated ◽  
Water Bath Heating ◽  
A Current

A new carbon-coated nickel sulfides electrode material (NST/CNTs@C) has been synthesized through an easy-to-operate process: NiS2/CNTs which was prepared by a hydrothermal method reacted with BTC (1,3,5-benzenetricarboxylic acid) under the condition of water bath heating to obtain the precursor, and then the precursor was calcined in 450 °C under a nitrogen atmosphere to obtain NST/CNTs@C. The electrochemical performance of NST/CNTs@C has been greatly improved because the formation of a carbon-coated layer effectively increased the specific surface area, reduced the charge transport resistance and inhibited the morphological change of nickel sulfides in the charge–discharge process. Compared with pure NiS2 and NiS2/CNTs, NST/CNTs@C presented great specific capacitance (620 F·g−1 at a current density of 1 A·g−1), better cycle stability (49.19% capacitance retention after 1000 cycles) and more superior rate capability (when the current density was raised to 10 A·g−1 the specific capacitance remained 275 F·g−1).

scholarly journals One-Step Hydrothermal Synthesis of a CoTe@rGO Electrode Material for Supercapacitors

2021 ◽  
Author(s):  
Tianrui Wang ◽  
Yupeng Su ◽  
Mi Xiao ◽  
Meilian Zhao ◽  
Tingwu Zhao ◽  
...  
Keyword(s):  
Energy Density ◽  
Specific Capacitance ◽  
Power Density ◽  
Current Density ◽  
Electrode Material ◽  
High Energy ◽  
Cycling Stability ◽  
High Energy Density ◽  
One Step ◽  
Charge Discharge

AbstractCoTe@reduced graphene oxide (CoTe@rGO) electrode materials for supercapacitors were prepared by a one-step hydrothermal method in this paper. Compared with that of pure CoTe, the electrochemical performance of CoTe@rGO was significantly improved. The results showed that the optimal CoTe@rGO electrode material has a remarkably high specific capacitance of 810.6 F/g at a current density of 1 A/g. At 5 A/g, the synthesized material retained 77.2% of its initial capacitance even after 5000 charge/discharge cycles, thereby demonstrating good cycling stability. Moreover, even at a high current density of 20 A/g, the composite electrode retained 79.0% of its specific capacitance at 1 A/g, thus confirming its excellent rate performance. An asymmetric supercapacitor (ASC) with a wider potential window and higher energy density was assembled by using 3 M KOH as the electrolyte, the CoTe@rGO electrode as the positive electrode, and active carbon as the negative electrode. The operating voltage of the supercapacitor could be increased to 1.6 V, and its specific capacitance could reach 112.6 F/g at 1 A/g. The specific capacitance retention rate of the fabricated supercapacitor after 5000 charge/discharge cycles at 5 A/g was 87.1%, which confirms its excellent cycling stability. In addition, the ASC revealed a high energy density of 40.04 W·h/kg at a power density of 799.91 W/kg and a high power density of 4004.93 W/kg at an energy density of 33.43 W·h/kg. These results collectively show that CoTe@rGO materials have broad application prospects.

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