scholarly journals Joule Heating-Induced Carbon Fibers for Flexible Fiber Supercapacitor Electrodes

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5255
Author(s):  
Jin Gu Kang ◽  
Gang Wang ◽  
Sung-Kon Kim

Microscale fiber-based supercapacitors have become increasingly important for the needs of flexible, wearable, and lightweight portable electronics. Fiber electrodes without pre-existing cores enable a wider selection of materials and geometries than is possible through core-containing electrodes. The carbonization of fibrous precursors using an electrically driven route, different from a conventional high-temperature process, is particularly promising for achieving this structure. Here, we present a facile and low-cost process for producing high-performance microfiber supercapacitor electrodes based on carbonaceous materials without cores. Fibrous carbon nanotubes-agarose composite hydrogels, formed by an extrusion process, are converted to a composite fiber consisting of carbon nanotubes (CNTs) surrounded by an amorphous carbon (aC) matrix via Joule heating. When assembled into symmetrical two-electrode cells, the composite fiber (aC-CNTs) supercapacitor electrodes deliver a volumetric capacitance of 5.1 F cm−3 even at a high current density of 118 mA cm−3. Based on electrochemical impedance spectroscopy analysis, it is revealed that high electrochemical properties are attributed to fast response kinetics with a characteristic time constant of 2.5 s. The aC-CNTs fiber electrodes exhibit a 94% capacitance retention at 14 mA cm−3 for at least 10,000 charge-discharge cycles even when deformed (90° bend), which is essentially the same as that (96%) when not deformed. The aC-CNTs fiber electrodes also demonstrate excellent storage performance under mechanical deformation—for example, 1000 bending-straightening cycles.

Author(s):  
Yaofeng Wang ◽  
Fan Wang ◽  
Yang Kong ◽  
Lei Wang ◽  
Qinchuan Li

Abstract High-performance bioartificial muscles with low-cost, large bending deformation, low actuation voltage, and fast response time have drawn extensive attention as the development of human-friendly electronics in recent years. Here, we report a high-performance ionic bioartificial muscle based on the bacterial cellulose (BC)/ionic liquid (IL)/multi-walled carbon nanotubes (MWCNT) nanocomposite membrane and PEDOT:PSS electrode. The developed ionic actuator exhibits excellent electro-chemo-mechanical properties, which are ascribed to its high ionic conductivity, large specific capacitance, and ionically crosslinked structure resulting from the strong ionic interaction and physical crosslinking among BC, IL, and MWCNT. In particular, the proposed BC-IL-MWCNT (0.10 wt%) nanocomposite exhibited significant increments of Young's modulus up to 75% and specific capacitance up to 77%, leading to 2.5 times larger bending deformation than that of the BC-IL actuator. More interestingly, bioinspired applications containing artificial soft robotic finger and grapple robot were successfully demonstrated based on high-performance BC-IL-MWCNT actuator with excellent sensitivity and controllability. Thus, the newly proposed BC-IL-MWCNT bioartificial muscle will offer a viable pathway for developing next-generation artificial muscles, soft robotics, wearable electronic products, flexible tactile devices, and biomedical instruments.


Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3244
Author(s):  
Jiuzhou Zhao ◽  
Zhenjun Li ◽  
Matthew Thomas Cole ◽  
Aiwei Wang ◽  
Xiangdong Guo ◽  
...  

The nanocone-shaped carbon nanotubes field-emitter array (NCNA) is a near-ideal field-emitter array that combines the advantages of geometry and material. In contrast to previous methods of field-emitter array, laser ablation is a low-cost and clean method that does not require any photolithography or wet chemistry. However, nanocone shapes are hard to achieve through laser ablation due to the micrometer-scale focusing spot. Here, we develop an ultraviolet (UV) laser beam patterning technique that is capable of reliably realizing NCNA with a cone-tip radius of ≈300 nm, utilizing optimized beam focusing and unique carbon nanotube–light interaction properties. The patterned array provided smaller turn-on fields (reduced from 2.6 to 1.6 V/μm) in emitters and supported a higher (increased from 10 to 140 mA/cm2) and more stable emission than their unpatterned counterparts. The present technique may be widely applied in the fabrication of high-performance CNTs field-emitter arrays.


2009 ◽  
Vol 2009 ◽  
pp. 1-24 ◽  
Author(s):  
Yun Wang ◽  
John T. W. Yeow

Gas sensors have attracted intensive research interest due to the demand of sensitive, fast response, and stable sensors for industry, environmental monitoring, biomedicine, and so forth. The development of nanotechnology has created huge potential to build highly sensitive, low cost, portable sensors with low power consumption. The extremely high surface-to-volume ratio and hollow structure of nanomaterials is ideal for the adsorption of gas molecules. Particularly, the advent of carbon nanotubes (CNTs) has fuelled the inventions of gas sensors that exploit CNTs' unique geometry, morphology, and material properties. Upon exposure to certain gases, the changes in CNTs' properties can be detected by various methods. Therefore, CNTs-based gas sensors and their mechanisms have been widely studied recently. In this paper, a broad but yet in-depth survey of current CNTs-based gas sensing technology is presented. Both experimental works and theoretical simulations are reviewed. The design, fabrication, and the sensing mechanisms of the CNTs-based gas sensors are discussed. The challenges and perspectives of the research are also addressed in this review.


2018 ◽  
Vol 8 (9) ◽  
pp. 1514 ◽  
Author(s):  
Bao Chang ◽  
Hsiu-Fen Tsai ◽  
Yun-Da Lee

This paper first integrates big data tools—Hive, Impala, and SparkSQL—which support SQL-like queries for rapid data retrieval in big data. The three introduced tools are not only suitable for operating in business intelligence to serve high-performance data retrieval, but they are also an open-source software solution with low cost for small-to-medium enterprise use. In practice, the proposed approach provides an in-memory cache and an in-disk cache to achieve a very fast response to a query if a cache hit occurs. Moreover, this paper develops so-called platform selection that is able to select the appropriate tool dealing with input query with effectiveness and efficiency. As a result, the speed of job execution of proposed approach using platform selection is 2.63 times faster than Hive in the Case 1 experiment, and 4.57 times faster in the Case 2 experiment.


RSC Advances ◽  
2017 ◽  
Vol 7 (5) ◽  
pp. 2621-2628 ◽  
Author(s):  
Zhenyu Li ◽  
Omid Zabihi ◽  
Jinfeng Wang ◽  
Quanxiang Li ◽  
Jiemin Wang ◽  
...  

Polyacrylonitrile (PAN) reinforced with nano-carbons such as graphene (Gr) and carbon nanotubes (CNTs) provides great opportunity for the development of low-cost and high-performance carbon materials.


2021 ◽  
Vol 8 ◽  
Author(s):  
Junfeng Li ◽  
Xianzi Zhou ◽  
Kai Lu ◽  
Chao Ma ◽  
Liang Li ◽  
...  

Molybdenum sulfide (MoS2) has become a potential anode of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to its high theoretical capacity and low cost. However, the volume expansion, poor electrical conductivity and dissolution of polysulfides in the electrolyte during the cycling process severely limited its applications. Herein, few-layered MoS2@N-doped carbon (F-MoS2@NC) was synthesized through a facile solvothermal and annealing process. It was found that the addition of N-doped carbon precursor could significantly promote the formation of few-layered MoS2 and improve the performances of lithium and sodium storage. A high reversible capacity of 482.6 mA h g−1 at a high current density of 2000 mA g−1 could be obtained for LIBs. When used as anode material for SIBs, F-MoS2@NC hybrids could maintain a reversible capacity of 171 mA h g−1 at a high current density of 1,000 mA g−1 after 600 cycles. This work should provide new insights into carbon hybrid anode materials for both LIBs and SIBs.


Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 133
Author(s):  
Piyanut Pinyou ◽  
Vincent Blay ◽  
Kantapat Chansaenpak ◽  
Sireerat Lisnund

The determination of paracetamol is a common need in pharmaceutical and environmental samples for which a low-cost, rapid, and accurate sensor would be highly desirable. We develop a novel pencil graphite lead electrode (PGE) modified with single-wall carbon nanotubes (SWCNTs) and polyvinylpyrrolidone (PVP) polymer (PVP/SWCNT/PGE) for the voltammetric quantification of paracetamol. The sensor shows remarkable analytical performance in the determination of paracetamol at neutral pH, with a limit of detection of 0.38 μM and a linear response from 1 to 500 μM using square-wave voltammetry (SWV), which are well suited to the analysis of pharmaceutical preparations. The introduction of the polymer PVP can cause dramatic changes in the sensing performance of the electrode, depending on its specific architecture. These effects were investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The results indicate that the co-localization and dispersion of PVP throughout the carbon nanotubes on the electrode are key to its superior electrochemical performance, facilitating the electrical contact between the nanotubes and with the electrode surface. The application of this sensor to commercial syrup and tablet preparations is demonstrated with excellent results.


2020 ◽  
Vol 44 (7-8) ◽  
pp. 487-493
Author(s):  
Hong-Yan Lin ◽  
Yi-Fei Wang ◽  
Yuan Tian ◽  
Guo-Cheng Liu ◽  
Jian Luan

A CuI coordination polymer based on the N,N’-bis(3-pyridinecarboxamide)-1,4-butane (3-dpyb) ligand, namely [Cu(3-dpyb)0.5Cl], is hydrothermally synthesized and structurally characterized, and is used as a catalyst precursor to synthesize multi-walled carbon nanotubes. Interestingly, the as-grown multi-walled carbon nanotubes exhibit high performance in removing dyes from solution and can serve as a low-cost and fast adsorbent. In addition, the adsorption behavior of this new adsorbent fits well with the Freundlich isotherm and the pseudo-second-order kinetic model.


Small ◽  
2016 ◽  
Vol 12 (14) ◽  
pp. 1859-1865 ◽  
Author(s):  
Gi-Cheol Son ◽  
Sang-Soo Chee ◽  
Ji-Hyun Jun ◽  
Myungwoo Son ◽  
Sun Sook Lee ◽  
...  

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