scholarly journals Hydrothermal Synthesis of Co-Doped NiSe2 Nanowire for High-Performance Asymmetric Supercapacitors

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1468 ◽  
Author(s):  
Yun Gu ◽  
Le-Qing Fan ◽  
Jian-Ling Huang ◽  
Cheng-Long Geng ◽  
Jian-Ming Lin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Energy Density ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrode Materials ◽  
Nickel Foam ◽  
High Energy ◽  
High Energy Density ◽  
Asymmetric Supercapacitor

Co@NiSe2 electrode materials were synthesized via a simple hydrothermal method by using nickel foam in situ as the backbone and subsequently characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and a specific surface area analyzer. Results show that the Co@NiSe2 electrode exhibits a nanowire structure and grows uniformly on the nickel foam base. These features make the electrode show a relatively high specific surface area and electrical conductivity, and thus exhibit excellent electrochemical performance. The obtained electrode has a high specific capacitance of 3167.6 F·g−1 at a current density of 1 A·g−1. To enlarge the potential window and increase the energy density, an asymmetric supercapacitor was assembled by using a Co@NiSe2 electrode and activated carbon acting as positive and negative electrodes, respectively. The prepared asymmetrical supercapacitor functions stably under the potential window of 0–1.6 V. The asymmetric supercapacitor can deliver a high energy density of 50.0 Wh·kg−1 at a power density of 779.0 W·kg−1. Moreover, the prepared asymmetric supercapacitor exhibits a good rate performance and cycle stability.

Electrospun flexible lignin/polyacrylonitrile-based carbon nanofiber and its application in electrode materials for supercapacitors

2021 ◽  
pp. 004051752110371
Author(s):  
Hong Wu ◽  
Chengkun Liu ◽  
Zhiwei Jiang ◽  
Zhi Yang ◽  
Xue Mao ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrode Materials ◽  
Carbon Nanofiber ◽  
Electrochemical Impedance ◽  
Nickel Foam ◽  
Average Diameter ◽  
Raw Material ◽  
Equivalent Series Resistance

In this study, a lignin/polyacrylonitrile (PAN) composite nanofiber membrane is prepared by electrospinning and used as the precursor to prepare flexible carbon nanofibers (CNFs) through pre-oxidation and carbonization. The micromorphology, crystal structure, pore size distribution and specific surface area of the CNFs are characterized by field emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy and specific surface adsorption analysis, respectively. The electrochemical properties of the CNF membrane are also investigated by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy due to its potential application in binder-free electrode materials for supercapacitors. We successfully prepared flexible CNFs with an average diameter of about 539 nm and a specific surface area of 1053.78 m2/g when the mass ratio of lignin to PAN was 9:1 in a solution concentration of 28 wt%. The CNFs are loaded onto nickel foam to prepare the electrode materials for supercapacitors without a binder. When the current density is 0.5 A/g, the specific capacitance could be up to 201.27 F/g and the equivalent series resistance is only 0.57 Ω, which shows an excellent electrochemical performance. This study not only provides a theoretical basis for the high-value utilization of lignin and the preparation of flexible lignin/PAN-based CNFs, but also provides a new type of environmentally friendly raw material for the electrodes of supercapacitors and could be helpful to alleviate the energy crisis and environmental pollution.

Architecture engineering of supercapacitor electrode materials

2016 ◽  
Vol 09 (01) ◽  
pp. 1640001 ◽  
Author(s):  
Kunfeng Chen ◽  
Gong Li ◽  
Dongfeng Xue
Keyword(s):  
Specific Surface ◽  
Specific Capacitance ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrode Materials ◽  
Electronic Conductivity ◽  
High Specific Capacitance ◽  
High Energy ◽  
Supercapacitor Electrode

The biggest challenge for today’s supercapacitor systems readily possessing high power density is their low energy density. Their electrode materials with controllable structure, specific surface area, electronic conductivity, and oxidation state, have long been highlighted. Architecture engineering of functional electrode materials toward powerful supercapacitor systems is becoming a big fashion in the community. The construction of ion-accessible tunnel structures can microscopically increase the specific capacitance and materials utilization; stiff 3D structures with high specific surface area can macroscopically assure high specific capacitance. Many exciting findings in electrode materials mainly focus on the construction of ice-folded graphene paper, in situ functionalized graphene, in situ crystallizing colloidal ionic particles and polymorphic metal oxides. This feature paper highlights some recent architecture engineering strategies toward high-energy supercapacitor electrode systems, including electric double-layer capacitance (EDLC) and pseudocapacitance.

NaCl-templated synthesis of hierarchical porous carbon with extremely large specific surface area and improved graphitization degree for high energy density lithium ion capacitors

2018 ◽  
Vol 6 (35) ◽  
pp. 17057-17066 ◽  
Author(s):  
Ruiying Shi ◽  
Cuiping Han ◽  
Hongfei Li ◽  
Lei Xu ◽  
Tengfei Zhang ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Lithium Ion ◽  
High Energy ◽  
High Specific Surface Area ◽  
High Energy Density ◽  
Templated Synthesis ◽  
Graphitization Degree ◽  
Hierarchical Porous

This work demonstrates egg-white derived activated carbon with exceptionally high specific surface area and improved graphitization degree using NaCl template.

High Energy Density Asymmetric Supercapacitor Based on NiCo2S4/CNTs Hybrid and Carbon Nanotube Paper Electrodes

2019 ◽  
Vol 07 (01n02) ◽  
pp. 1950004 ◽  
Author(s):  
Muhammad Sajjad ◽  
Xu Chen ◽  
Chunxin Yu ◽  
Linlin Guan ◽  
Shuyu Zhang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Energy Density ◽  
Specific Capacitance ◽  
Current Density ◽  
Electrode Materials ◽  
High Energy ◽  
Hybrid Nanostructures ◽  
High Energy Density ◽  
Asymmetric Supercapacitor ◽  
Charge Discharge

NiCo2S4/CNTs (NCS/CNTs) hybrid nanostructures have been synthesized by a facile one-step solvothermal method with varying content of CNTs. The structure and morphology of the synthesized NCS/CNTs hybrid revealed the formation of platelets anchored on the CNT matrix. When evaluated as electrode materials for supercapacitor, the as-synthesized NCS/CNT-1 hybrid (with 1% of CNT) manifested remarkable specific capacitance of 1690[Formula: see text]F[Formula: see text]g[Formula: see text] at the current density of 5[Formula: see text]A[Formula: see text]g[Formula: see text]. More importantly, an asymmetric supercapacitor (ASC) assembled based on NCS/CNT-1 as positive electrode and carbon nanotube paper (CNP) as a negative electrode delivered high energy density of 58[Formula: see text]Wh[Formula: see text]kg[Formula: see text] under power density of 8[Formula: see text]kW[Formula: see text]kg[Formula: see text]. Furthermore, the ASC device exhibited high cycling stability and 77.7% of initial specific capacitance retention after 7000 charge–discharge cycles at a current density of 8[Formula: see text]A[Formula: see text]g[Formula: see text]. The large enhancement in the electrochemical performance is attributed to the benefits of the nanostructured architecture, including good mechanical stability, high electrical conductivity as well as buffering for the volume changes during charge–discharge process. These convincing results show that NCS/CNTs hybrid nanostructures are promising electrode materials for high energy density supercapacitors (SCs).

scholarly journals Application of Porous Carbon Material As Electrode Material of Polyvalent Cation Electric Double Layer Capacitor (EDLC) for High Capacity

2020 ◽  
Author(s):  
Tsubasa Okamura ◽  
Kiyoharu Nakagawa
Keyword(s):  
Energy Density ◽  
Specific Surface ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Electrode Material ◽  
Electric Double Layer ◽  
Electrode Materials ◽  
Power Supplies ◽  
Adsorption And Desorption

Electric double layer capacitors (EDLC) are charged and discharged by the physical adsorption and desorption of electrolyte ions on the electrode surface. EDLC has the advantages of high-speed charge and discharge and long life. EDLC is used in memory backup power supplies such as personal computers and energy regenerative systems for power regenerative brakes in hybrid vehicles. In recent years, demand for applications such as in-vehicle power supplies has increased. Therefore, high energy density is required. The energy density increases by increasing the electrostatic capacity and the potential. In the conventional adsorption and desorption of monovalent cations, only one electron can be exchanged for each cation. In adsorption and desorption, two electrons can be exchanged for each cation. Therefore, it was considered that the capacitance can be increased by using an electrolyte of divalent cations.In this study, Ca2+ was used as the divalent cation. As an organic electrolyte, propylene carbonate (PC) and γ-butyrolactone (GBL), which are commonly used in EDLC research as a solvent and can dissolve the electrolyte used. In addition, the dependence of the specific surface area and pore characteristics of the electrode material on the capacity was examined. Activated carbon and carbon gel were used as electrode materials. The capacitance of Ca2+ electrolyte increased when GBL was used as the solvent. Capacitance increased depending on the specific surface area of electrode materials.

Pitaya peel derived carbons with ultra-high specific surface area for solid-state flexible asymmetric supercapacitors

2021 ◽  
pp. 2150022
Author(s):  
Wei Yang ◽  
Cailian Zhu ◽  
Li Li ◽  
Weihua Wang ◽  
Zheng Yang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Energy ◽  
High Specific Surface Area ◽  
High Energy Density ◽  
Super Capacitor ◽  
Hierarchical Porous ◽  
Very High Energy ◽  
Pre Treatment

In this paper, a well-designed process to fabricate bio-mass carbon with ultra-high specific surface area (UHSSA) and hierarchical porous (HP) structure is achieved. The process pre-treating with ethanol and KOH cooperatively is first introduced to optimize the microstructure and porosity. The as-prepared carbons present an UHSSA of ca. 3521 m2 [Formula: see text] g[Formula: see text], with large amounts of micro and mesopores. The assembled asymmetric flexible super-capacitor (SC) holds very high energy density of 49.9 Wh [Formula: see text] kg[Formula: see text] at 90 W [Formula: see text] kg[Formula: see text], and 10.3 Wh [Formula: see text] kg[Formula: see text] at the higher power density of 9 kW [Formula: see text] kg[Formula: see text], demonstrating that the device possesses long cyclic life and well stability. The exciting results reveal that our study provides an effective approach to biomass recycling by pre-treatment of ethanol and KOH producing HP carbons possessing ultra-high SSA for high-energy storage applications.

Advanced asymmetric supercapacitors based on Ni3(PO4)2@GO and Fe2O3@GO electrodes with high specific capacitance and high energy density

RSC Advances ◽  
2015 ◽  
Vol 5 (52) ◽  
pp. 41721-41728 ◽  
Author(s):  
Jia-Jia Li ◽  
Mao-Cheng Liu ◽  
Ling-Bin Kong ◽  
Dan Wang ◽  
Yu-Mei Hu ◽  
...  
Keyword(s):  
Energy Density ◽  
Specific Capacitance ◽  
Electrode Materials ◽  
High Specific Capacitance ◽  
High Energy ◽  
High Energy Density ◽  
Asymmetric Supercapacitor ◽  
Asymmetric Supercapacitors

Ni3(PO4)2@GO and Fe2O3@GO have been successfully synthesized as electrode materials, and they have been used to assemble an asymmetric supercapacitor (Fe2O3@GO//Ni3(PO4)2@GO), which exhibited a high energy density.

scholarly journals Nitrogen-enriched graphene framework from a large-scale magnesiothermic conversion of CO2 with synergistic kinetics for high-power lithium-ion capacitors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Chen Li ◽  
Xiong Zhang ◽  
Kai Wang ◽  
Xianzhong Sun ◽  
Yanan Xu ◽  
...  
Keyword(s):  
Energy Density ◽  
High Power ◽  
Power Output ◽  
Large Scale ◽  
Electrode Materials ◽  
Lithium Ion ◽  
High Energy ◽  
High Energy Density ◽  
Chemical Doping ◽  
Lithium Ion Capacitor

AbstractLithium-ion capacitors are envisaged as promising energy-storage devices to simultaneously achieve a large energy density and high-power output at quick charge and discharge rates. However, the mismatched kinetics between capacitive cathodes and faradaic anodes still hinder their practical application for high-power purposes. To tackle this problem, the electron and ion transport of both electrodes should be substantially improved by targeted structural design and controllable chemical doping. Herein, nitrogen-enriched graphene frameworks are prepared via a large-scale and ultrafast magnesiothermic combustion synthesis using CO2 and melamine as precursors, which exhibit a crosslinked porous structure, abundant functional groups and high electrical conductivity (10524 S m−1). The material essentially delivers upgraded kinetics due to enhanced ion diffusion and electron transport. Excellent capacities of 1361 mA h g−1 and 827 mA h g−1 can be achieved at current densities of 0.1 A g−1 and 3 A g−1, respectively, demonstrating its outstanding lithium storage performance at both low and high rates. Moreover, the lithium-ion capacitor based on these nitrogen-enriched graphene frameworks displays a high energy density of 151 Wh kg−1, and still retains 86 Wh kg−1 even at an ultrahigh power output of 49 kW kg−1. This study reveals an effective pathway to achieve synergistic kinetics in carbon electrode materials for achieving high-power lithium-ion capacitors.

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