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Journal ArticleDOI: 10.1039/D0TA10263F

High-performance and thermostable wire supercapacitors using mesoporous activated graphene deposited on continuous multilayer graphene

02 Mar 2021-Journal of Materials Chemistry (Royal Society of Chemistry (RSC))-Vol. 9, Iss: 8, pp 4800-4809
Abstract: Wire supercapacitors are promising flexible power sources for wearable devices because of their high power density, long cycle life, and mechanical flexibility However, obtaining high energy density along with thermal stability is essential for developing sustainable wire supercapacitors that use a charge storage mechanism based on electric double-layer (EDL) formation In this study, activated graphene (AG) was coated onto continuous graphene deposited on Cu wire current collectors using electrophoretic deposition, forming wire supercapacitors with high power and energy density as well as outstanding thermal stability and chemical resistance The incorporation of AG, which has a high specific surface area, enabled nearly ideal capacitive behaviors of the devices with high specific areal capacitances of up to 1303 mF cm−2 Multilayer graphene grown by chemical vapor deposition (CVD) on Cu wires worked as a multifunctional intermediate layer for enhancing the interfacial contact between the electrode and the current collector as well as the electrical conductivity, chemical resistance, and thermal stability of the Cu wire The great synergy between the AG electrode material and CVD-grown graphene on Cu current collectors achieved high energy densities of up to 454 μW h cm−2 and outstanding power densities of up to 161 mW cm−2 with excellent cycling stability (∼938% capacitance retention over 10 000 cycles) Furthermore, the wire supercapacitors exhibited stable EDL charge storage capability for temperatures ranging from 7 to 80 °C This unique architecture of wire supercapacitors promises great potential for high-performance and thermostable energy storage, and can be embedded in future wearable electronics and smart textiles

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Topics: Graphene (55%), Supercapacitor (53%), Energy storage (52%) ... show more
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6 results found


Journal ArticleDOI: 10.1039/D1NJ01513C
Jia-hua Liu1, Jia-hua Liu2, Xiao-ying Xu1, Chen Liu1  +1 moreInstitutions (2)
Abstract: With the ongoing advance of flexible energy storage products for commercial portable electronics application, the fundamental comprehension of the temperature-dependence for supercapacitors is in urgent demand. Although polypyrrole (PPy) has been extensively employed as electrodes for supercapacitor systems, their electrochemical response to extreme thermal environments is rarely discussed. In this work, PPy was rationally constructed on the surface of carbon cloth (CC) as electrodes and a type of high-performance flexible symmetric supercapacitor was assembled with a PVA-H3PO4 gel electrolyte. The electrochemical performance of the supercapacitors was systematically investigated at various surrounding temperatures from 0 °C to 60 °C using cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy measurements. The results demonstrated that the areal specific capacitance of the CC/PPy supercapacitor at 0.5 mA cm−2 increased from 52.91 mF cm−2 to 75.08 mF cm−2 and the internal resistance fell by 71.4% when the operating temperature rose from 0 °C to 60 °C. Moreover, cycling stability dropped and the self-discharge behavior accelerated in the supercapacitors with the gradual increase in the external temperature. This study provides a fundamental understanding of the temperature-dependent pseudocapacitive performance of PPy-based flexible supercapacitors, which gives a valuable reference for energy storage system applications.

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Topics: Supercapacitor (53%)

2 Citations


Open accessJournal ArticleDOI: 10.3390/NANO11040893
TaeGyeong Lim1, TaeYoung Kim2, Ji Won Suk1Institutions (2)
31 Mar 2021-Nanomaterials
Abstract: A porous Cu (P-Cu) mesh was used as a current collector and its morphological effect on the supercapacitor performance was investigated. A porous surface was obtained by thermally annealing the Cu mesh using ammonia gas. Hierarchically porous activated graphene (AG) with a high specific surface area (SSA) was deposited on the P-Cu mesh using electrophoretic deposition, aided by graphene oxide (GO). GO was thermally converted to electrically conductive reduced graphene oxide (rGO). The AG/rGO that was deposited on the P-Cu mesh achieved a high specific capacitance of up to 140.0 F/g and a high energy density of up to 3.11 Wh/kg at a current density of 2 A/g in 6 m KOH aqueous electrolyte. The high SSA of AG and the porous surface morphology of the Cu mesh allowed efficient electric double-layer formation and charge transport. This work offers an alternative to improve supercapacitors by combining a porous metallic current collector with porous AG.

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Topics: Graphene (54%), Electrophoretic deposition (53%), Supercapacitor (51%) ... show more

1 Citations


Open accessJournal ArticleDOI: 10.3390/NANO11040865
29 Mar 2021-Nanomaterials
Abstract: The emergence of graphene paper comprising well-stacked graphene flakes has promoted the application of graphene-based materials in diverse fields such as energy storage devices, membrane desalination, and actuators. The fundamental properties of graphene paper such as mechanical, electrical, and thermal properties are critical to the design and fabrication of paper-based devices. In this study, the interlayer interactions in graphene paper were investigated by double cantilever beam (DCB) fracture tests. Graphene papers fabricated by flow-directed stacking of electrochemically exfoliated few-layer graphene flakes were mechanically separated into two parts, which generated force-displacement responses of the DCB sample. The analysis based on fracture mechanics revealed that the interlayer separation energy of the graphene paper was 9.83 ± 0.06 J/m2. The results provided a fundamental understanding of the interfacial properties of graphene papers, which will be useful for developing paper-based devices with mechanical integrity.

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Topics: Graphene oxide paper (70%), Graphene (62%)

1 Citations


Journal ArticleDOI: 10.1016/J.CEJ.2021.131895
Rajneesh Kumar Mishra1, Gyu Jin Choi1, Hyeon Jong Choi1, Jay Singh2  +5 moreInstitutions (4)
Abstract: We report an eco-friendly, in-situ, and one-step synthesis of ZnO-Co3O4 core-shell heterostructure (ZC-CSH) using the hydrothermal process as a transcendent nanomaterial for the supercapacitor applications. The ZC-CSH SSC showed a wide potential window (1.6 V), the excellent specific capacitance of 177.0F g−1 at 1.4 A g−1, high energy density (39.3 W h kg−1), and power density (19064.3 W kg−1). Further, the ZC-CSH SSC revealed excellent stability of 92.8 % after 10,000 cycles at 12.4 A g−1 using galvanostatic charging-discharging. Besides, the ZC-CSH SSC unraveled the outstanding stability of 96.1 % after the 8 h Voltage holding tests (VHT) at 1.6 V + 8 h Self-discharge tests (SDT). Moreover, the ZC-CSH SSC indicated a trivial leakage current of 0.06, 0.11, 0.15, and 0.17 mA during 2, 4, 6, and 8 h VHT, respectively. The ZC-CSH SSC demonstrated a voltage drop from 1.6 V to 0.39, 0.38, 0.37, and 0.36 V after 2, 4, 6, and 8 h VHT and SDT. To understand the ZC-CSH SSC's self-discharge behavior, this work explored the insights of the self-discharge mechanisms based on two thermodynamic processes, ionic concentration gradient (diffusion-control model) and potential difference (potential-driven model). Also, according to the tight-bonding (strong interactions) and loose-bonding (weak interactions), this work envisaged electrolyte ions' interactions with electrode materials to explore the coherent insights of the self-discharge behavior of the ZC-CSH SSC. It is concluded that this approach can lead to an unwavering performance of the ZC-CSH SSC for electronic portable futuristic gadgets.

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1 Citations


Journal ArticleDOI: 10.1016/J.APSUSC.2021.151243
Yonas Tsegaye Megra1, Soomook Lim1, TaeGyeong Lim1, Seung Ryul Na2  +1 moreInstitutions (2)
Abstract: Because graphene is placed on a rigid or flexible substrate for future applications such as transparent or flexible electronic devices, the interfacial characteristics between graphene and the underlying substrate are of great importance for developing mechanically and electrically reliable devices. In this work, the interaction strength of large-area monolayer graphene transferred on SiO2/Si was adjusted by thermal treatments, and its adhesion energy was measured by mode I fracture tests using a double cantilever beam (DCB) configuration with a laminated composite (Si/SiO2/graphene/epoxy/SiO2/Si). Mechanical delamination of monolayer graphene from SiO2 showed an adhesion energy of 1.5 ± 0.15 J/m2. It was found that thermal annealing of graphene on SiO2 at 300 and 450 °C increased the adhesion energy to 2.2 ± 0.20 and 4.6 ± 0.31 J/m2, respectively. Characterization of graphene on SiO2 using atomic force microscopy and Raman spectroscopy revealed that the enhanced adhesion energy was attributed to the improved conformal contacts of monolayer graphene with corrugated SiO2 surfaces.

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Topics: Graphene (62%), Adhesion (52%)

References
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60 results found


Journal ArticleDOI: 10.1351/PAC198557040603
Abstract: Mise au point comportant des definitions generales et la terminologie, la methodologie utilisee, les procedes experimentaux, les interpretations des donnees d'adsorption, les determinations de l'aire superficielle, et les donnees sur la mesoporosite et la microporosite

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18,120 Citations


Open accessJournal ArticleDOI: 10.1103/PHYSREVLETT.97.187401
Abstract: Graphene is the two-dimensional building block for carbon allotropes of every other dimensionality We show that its electronic structure is captured in its Raman spectrum that clearly evolves with the number of layers The D peak second order changes in shape, width, and position for an increasing number of layers, reflecting the change in the electron bands via a double resonant Raman process The G peak slightly down-shifts This allows unambiguous, high-throughput, nondestructive identification of graphene layers, which is critically lacking in this emerging research area

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Topics: Bilayer graphene (64%), Graphene nanoribbons (62%), Graphene (58%) ... show more

12,229 Citations


Open accessJournal ArticleDOI: 10.1126/SCIENCE.1171245
Xuesong Li1, Weiwei Cai1, Jinho An1, Seyoung Kim1  +9 moreInstitutions (2)
05 Jun 2009-Science
Abstract: Graphene has been attracting great interest because of its distinctive band structure and physical properties. Today, graphene is limited to small sizes because it is produced mostly by exfoliating graphite. We grew large-area graphene films of the order of centimeters on copper substrates by chemical vapor deposition using methane. The films are predominantly single-layer graphene, with a small percentage (less than 5%) of the area having few layers, and are continuous across copper surface steps and grain boundaries. The low solubility of carbon in copper appears to help make this growth process self-limiting. We also developed graphene film transfer processes to arbitrary substrates, and dual-gated field-effect transistors fabricated on silicon/silicon dioxide substrates showed electron mobilities as high as 4050 square centimeters per volt per second at room temperature.

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Topics: Graphene oxide paper (65%), Graphene nanoribbons (64%), Aerographene (63%) ... show more

9,917 Citations


Journal ArticleDOI: 10.1002/ADMA.201001068
Yanwu Zhu1, Shanthi Murali1, Weiwei Cai1, Xuesong Li1  +3 moreInstitutions (1)
15 Sep 2010-Advanced Materials
Abstract: There is intense interest in graphene in fields such as physics, chemistry, and materials science, among others. Interest in graphene's exceptional physical properties, chemical tunability, and potential for applications has generated thousands of publications and an accelerating pace of research, making review of such research timely. Here is an overview of the synthesis, properties, and applications of graphene and related materials (primarily, graphite oxide and its colloidal suspensions and materials made from them), from a materials science perspective.

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Topics: Graphene (58%), Graphite oxide (57%)

7,753 Citations


Journal ArticleDOI: 10.1021/NL802558Y
Meryl D. Stoller1, Sungjin Park1, Yanwu Zhu1, Jinho An1  +1 moreInstitutions (1)
13 Sep 2008-Nano Letters
Abstract: The surface area of a single graphene sheet is 2630 m2/g, substantially higher than values derived from BET surface area measurements of activated carbons used in current electrochemical double layer capacitors. Our group has pioneered a new carbon material that we call chemically modified graphene (CMG). CMG materials are made from 1-atom thick sheets of carbon, functionalized as needed, and here we demonstrate in an ultracapacitor cell their performance. Specific capacitances of 135 and 99 F/g in aqueous and organic electrolytes, respectively, have been measured. In addition, high electrical conductivity gives these materials consistently good performance over a wide range of voltage scan rates. These encouraging results illustrate the exciting potential for high performance, electrical energy storage devices based on this new class of carbon material.

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Topics: Supercapacitor (57%), Potential applications of graphene (57%), Graphene (57%) ... show more

6,912 Citations