scholarly journals An Ultra-High-Energy Density Supercapacitor; Fabrication Based on Thiol-functionalized Graphene Oxide Scrolls

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 148 ◽  
Author(s):  
Janardhanan. Rani ◽  
Ranjith Thangavel ◽  
Se-I Oh ◽  
Yun Lee ◽  
Jae-Hyung Jang
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Energy Density ◽  
Power Density ◽  
Current Density ◽  
Electrode Materials ◽  
High Energy ◽  
High Energy Density ◽  
Functionalized Graphene Oxide ◽  
A Current

Present state-of-the-art graphene-based electrodes for supercapacitors remain far from commercial requirements in terms of high energy density. The realization of high energy supercapacitor electrodes remains challenging, because graphene-based electrode materials are synthesized by the chemical modification of graphene. The modified graphene electrodes have lower electrical conductivity than ideal graphene, and limited electrochemically active surface areas due to restacking, which hinders the access of electrolyte ions, resulting in a low energy density. In order to solve the issue of restacking and low electrical conductivity, we introduce thiol-functionalized, nitrogen-doped, reduced graphene oxide scrolls as the electrode materials for an electric double-layer supercapacitor. The fabricated supercapacitor exhibits a very high energy/power density of 206 Wh/kg (59.74 Wh/L)/496 W/kg at a current density of 0.25 A/g, and a high power/energy density of 32 kW/kg (9.8 kW/L)/9.58 Wh/kg at a current density of 50 A/g; it also operates in a voltage range of 0~4 V with excellent cyclic stability of more than 20,000 cycles. By suitably combining the scroll-based electrode and electrolyte material, this study presents a strategy for electrode design for next-generation energy storage devices with high energy density without compromising the power density.

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.

scholarly journals Ultrathin Ni1− x Co x S2 nanoflakes as high energy density electrode materials for asymmetric supercapacitors

2019 ◽  
Vol 10 ◽  
pp. 2207-2216 ◽  
Author(s):  
Xiaoxiang Wang ◽  
Teng Wang ◽  
Rusen Zhou ◽  
Lijuan Fan ◽  
Shengli Zhang ◽  
...  
Keyword(s):  
Energy Density ◽  
Electrochemical Performance ◽  
Power Density ◽  
Active Sites ◽  
Electrode Materials ◽  
Specific Capacity ◽  
High Energy ◽  
High Energy Density ◽  
Oxide Material ◽  
Energy Storage Devices

Transition metal compounds such as nickel cobalt sulfides (Ni–Co–S) are promising electrode materials for energy storage devices such as supercapacitors owing to their high electrochemical performance and good electrical conductivity. Developing ultrathin nanostructured materials is critical to achieving high electrochemical performance, because they possess rich active sites for electrochemical reactions, shortening the transport path of ions in the electrolyte during the charge/discharge processes. This paper describes the synthesis of ultrathin (around 10 nm) flower-like Ni1− x Co x S2 nanoflakes by using templated NiCo oxides. The as-prepared Ni1− x Co x S2 material retained the morphology of the initial NiCo oxide material and exhibited a much improved electrochemical performance. The Ni1− x Co x S2 electrode material exhibited a maximum specific capacity of 1066.8 F·g−1 (533.4 C·g−1) at 0.5 A·g−1 and a capacity retention of 63.4% at 20 A·g−1 in an asymmetric supercapacitor (ASC). The ASC showed a superior energy density of 100.5 Wh·kg−1 (at a power density of 1.5 kW·kg−1), an ultrahigh power density of 30 kW·kg−1 (at an energy density of 67.5 Wh·kg−1) and excellent cycling stability. This approach can be a low-cost way to mass-produce high-performance electrode materials for supercapacitors.

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 Biomass-Derived Graphene-Based Materials Embedded with Onion-Like Carbons for High Power Supercapacitors

2021 ◽  
Author(s):  
SungHoon Jung ◽  
Pham Thi Huong ◽  
Shalini Sahani ◽  
Kumud Malika Tripathi ◽  
Byung Jun Park ◽  
...  
Keyword(s):  
Energy Storage ◽  
Power Density ◽  
Current Density ◽  
High Power ◽  
Electrode Materials ◽  
High Current Density ◽  
3D Structure ◽  
High Energy ◽  
High Energy Density ◽  
High Power Density

Abstract We report a facile method to produce composites of hierarchically porous graphene-based materials embedded with onion-like carbons (Gr-OLCs) for high power density supercapacitors. Gr-OLCs were produced from the mixture of glucose, thiourea, and ammonium chloride, through the condensation reaction and subsequent blow into three-dimensional (3D) structure, and carbonization process. Owing to its high surface area, hierarchical pore distribution, and interconnected carbon networks embedded with onion-like carbons, this carbon exhibited the specific capacitance of 140 F g-1 at a high current density of 64 A g-1. Highly porous and interconnected carbon structure tend to facilitate the movement of electrolyte ions within the electrode and provide an efficient pathway for the movement of charge carriers, resulting in an exceptionally high power density of 1,737 kW kg-1, while maintaining its high energy density of 30 Wh kg-1 at current density of 256 A g-1. Studies on the complex capacitance of the cell revealed that these carbon electrodes possess stable energy storage features with minimal capacitive loss, achieving both high power and energy densities. This work may provide a new type of carbon-based electrode materials which can meet the requirements for high power energy storage devices.

scholarly journals Pseudocapacitive materials for electrochemical capacitors: from rational synthesis to capacitance optimization

2016 ◽  
Vol 4 (1) ◽  
pp. 71-90 ◽  
Author(s):  
Jie Wang ◽  
Shengyang Dong ◽  
Bing Ding ◽  
Ya Wang ◽  
Xiaodong Hao ◽  
...  
Keyword(s):  
Energy Density ◽  
Power Density ◽  
Rational Design ◽  
Electrode Materials ◽  
Electrochemical Capacitors ◽  
Rate Capability ◽  
High Energy ◽  
High Energy Density ◽  
Energy Storage Devices ◽  
Storage Devices

Abstract Among various energy-storage devices, electrochemical capacitors (ECs) are prominent power provision but show relatively low energy density. One way to increase the energy density of ECs is to move from carbon-based electric double-layer capacitors to pseudocapacitors, which manifest much higher capacitance. However, compared with carbon materials, the pseudocapacitive electrodes suffer from high resistance for electron and/or ion transfer, significantly restricting their capacity, rate capability and cyclability. Rational design of electrode materials offers opportunities to optimize their electrochemical performance, leading to devices with high energy density while maintaining high power density. This paper reviews the different approaches of electrodes striving to advance the energy and power density of ECs.

scholarly journals Na0.76V6O15/Activated Carbon Hybrid Cathode for High-Performance Lithium-Ion Capacitors

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 122
Author(s):  
Renwei Lu ◽  
Xiaolong Ren ◽  
Chong Wang ◽  
Changzhen Zhan ◽  
Ding Nan ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Energy Density ◽  
Power Density ◽  
Cathode Materials ◽  
Low Cost ◽  
Lithium Ion ◽  
High Energy ◽  
Cycling Stability ◽  
High Energy Density ◽  
Artificial Graphite

Lithium-ion hybrid capacitors (LICs) are regarded as one of the most promising next generation energy storage devices. Commercial activated carbon materials with low cost and excellent cycling stability are widely used as cathode materials for LICs, however, their low energy density remains a significant challenge for the practical applications of LICs. Herein, Na0.76V6O15 nanobelts (NaVO) were prepared and combined with commercial activated carbon YP50D to form hybrid cathode materials. Credit to the synergism of its capacitive effect and diffusion-controlled faradaic effect, NaVO/C hybrid cathode displays both superior cyclability and enhanced capacity. LICs were assembled with the as-prepared NaVO/C hybrid cathode and artificial graphite anode which was pre-lithiated. Furthermore, 10-NaVO/C//AG LIC delivers a high energy density of 118.9 Wh kg−1 at a power density of 220.6 W kg−1 and retains 43.7 Wh kg−1 even at a high power density of 21,793.0 W kg−1. The LIC can also maintain long-term cycling stability with capacitance retention of approximately 70% after 5000 cycles at 1 A g−1. Accordingly, hybrid cathodes composed of commercial activated carbon and a small amount of high energy battery-type materials are expected to be a candidate for low-cost advanced LICs with both high energy density and power 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.

scholarly journals Novel Lithium-Ion Capacitor Based on a NiO-rGO Composite

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3586
Author(s):  
Qi An ◽  
Xingru Zhao ◽  
Shuangfu Suo ◽  
Yuzhu Bai
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Power Density ◽  
High Power ◽  
Specific Capacity ◽  
Lithium Ion ◽  
High Energy ◽  
Cycle Life ◽  
High Energy Density ◽  
Lithium Ion Capacitor

Lithium-ion capacitors (LICs) have been widely explored for energy storage. Nevertheless, achieving good energy density, satisfactory power density, and stable cycle life is still challenging. For this study, we fabricated a novel LIC with a NiO-rGO composite as a negative material and commercial activated carbon (AC) as a positive material for energy storage. The NiO-rGO//AC system utilizes NiO nanoparticles uniformly distributed in rGO to achieve a high specific capacity (with a current density of 0.5 A g−1 and a charge capacity of 945.8 mA h g−1) and uses AC to provide a large specific surface area and adjustable pore structure, thereby achieving excellent electrochemical performance. In detail, the NiO-rGO//AC system (with a mass ratio of 1:3) can achieve a high energy density (98.15 W h kg−1), a high power density (10.94 kW kg−1), and a long cycle life (with 72.1% capacity retention after 10,000 cycles). This study outlines a new option for the manufacture of LIC devices that feature both high energy and high power densities.

scholarly journals Liquid Phase Synthesis of CoP Nanoparticles with High Electrical Conductivity for Advanced Energy Storage

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Guo-Qun Zhang ◽  
Bo Li ◽  
Mao-Cheng Liu ◽  
Shang-Ke Yuan ◽  
Leng-Yuan Niu
Keyword(s):  
Electrical Conductivity ◽  
Energy Storage ◽  
Liquid Phase ◽  
Specific Capacitance ◽  
Current Density ◽  
High Surface ◽  
High Surface Area ◽  
High Energy ◽  
High Energy Density ◽  
Energy Storage Materials

Transition metal phosphide alloys possess the metalloid characteristics and superior electrical conductivity and are a kind of high electrical conductive pseudocapacitive materials. Herein, high electrical conductive cobalt phosphide alloys are fabricated through a liquid phase process and a nanoparticles structure with high surface area is obtained. The highest specific capacitance of 286 F g−1 is reached at a current density of 0.5 A g−1. 63.4% of the specific capacitance is retained when the current density increased 16 times and 98.5% of the specific capacitance is maintained after 5000 cycles. The AC//CoP asymmetric supercapacitor also shows a high energy density (21.3 Wh kg−1) and excellent stability (97.8% of the specific capacitance is retained after 5000 cycles). The study provides a new strategy for the construction of high-performance energy storage materials by enhancing their intrinsic electrical conductivity.

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