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Paper or flexible supercapacitor*

Yujing Liu, Xuan Wang, Xiaohui Jiang, Xia Li, Liangmin Yu
N-Doped carbon nanomaterials have gained tremendous research interest in energy storage because of their high capacitance and chemical stability. Here, N-doped porous carbons (NPCs) with multiple shape-controlled and tunable morphologies are developed through a direct one-step pyrolysis/activation method. Typically, NPC-700-1, which is 5 nm thick and 6 μm wide, shows a high surface area (1591.5 m2 g-1) and hierarchical micro-, meso-, and macroporous architecture. The maximum specific capacitance of the as-prepared carbon nanosheets is 406 F g-1 at 1 A g-1 in KOH electrolyte...
November 29, 2018: Nanoscale
Caixia Zhou, Taotao Gao, Yujue Wang, Qilin Liu, Zhihan Huang, Xiaoxia Liu, Miaoqing Qing, Dan Xiao
Fiber supercapacitors (FSCs) are promising energy storage devices in portable and wearable smart electronics. Currently, a major challenge for FSCs is simultaneously achieving high volumetric energy and power densities. Herein, the microscale fiber electrode is designed by using carbon fibers as substrates and capillary channels as microreactors to space-confined hydrothermal assembling. As P-doped graphene oxide/carbon fiber (PGO/CF) and NiCo2 O4 -based graphene oxide/carbon fiber (NCGO/CF) electrodes are successfully prepared, their unique hybrid structures exhibit a satisfactory electrochemical performance...
November 27, 2018: Small
Jingxin Zhao, Yan Zhang, Yinan Huang, Jixun Xie, Xiaoxin Zhao, Chaowei Li, Jingyi Qu, Qichong Zhang, Juan Sun, Bing He, Qiulong Li, Conghua Lu, Xinhua Xu, Weibang Lu, Liqiang Li, Yagang Yao
Wearable fiber-shaped electronic devices have drawn abundant attention in scientific research fields, and tremendous efforts are dedicated to the development of various fiber-shaped devices that possess sufficient flexibility. However, most studies suffer from persistent limitations in fabrication cost, efficiency, the preparation procedure, and scalability that impede their practical application in flexible and wearable fields. In this study, a simple, low-cost 3D printing method capable of high manufacturing efficiency, scalability, and complexity capability to fabricate a fiber-shaped integrated device that combines printed fiber-shaped temperature sensors (FTSs) with printed fiber-shaped asymmetric supercapacitors (FASCs) is developed...
November 2018: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Huanan Peng, Guiju Qian, Ning Li, Yao Yao, Tian Lv, Shaokui Cao, Tao Chen
Despite being among the most researched energy storage devices, supercapacitors have often suffered from their relatively low operating voltage and energy density, which greatly limit their practical applications. In this work, asymmetric supercapacitors (ASCs) are developed by synergistically designing carbon nanotube composite electrodes with 3D porous structures. The resultant ASC devices exhibit an extended operating voltage of 1.8 V, much higher than that of symmetric supercapacitors (≤1.0 V). Significantly, the obtained ASC devices deliver ultrahigh volumetric energy density as high as 19...
November 2018: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Jaeho Choi, Taesob Oh, Myeongjin Kim, Jinglei Yang, Jooheon Kim
Graphene/Co(OH)₂ nanowire composite films were successfully synthesized using a simple three-step treatment, and the effect of the Co(OH)₂ nanowire content on the electrochemical properties of the composite films was studied in this study. One-dimensional Co(OH)₂ nanowires were homogeneously embedded and dispersed between the prepared graphene papers, forming a layered graphene/Co(OH)₂ nanowire hybrid structure. These composite films exhibited better electrochemical properties than the previously reported graphene composites with carbon spheres such as graphene/CNT composites...
March 1, 2019: Journal of Nanoscience and Nanotechnology
Xiao Liang, Lei Zhao, Qiufan Wang, Yun Ma, Daohong Zhang
Conventional flexible supercapacitors can work under consecutive bending, folding and even twisting without performance degradation. Nevertheless, these devices can hardly be used under large tensile strain. Flexible stretchable and healable supercapacitors are highly desired due to their many potential applications in electric devices. However, it is challenging to fabricate supercapacitors that can withstand stretchability and self-healability. Herein, we report a stretchable and self-healable supercapacitor based on a carbon nanotube@graphene@PANI nanowire film...
November 23, 2018: Nanoscale
Xiao Liang, Qiufan Wang, Yun Ma, Daohong Zhang
One-dimensional supercapacitors (SCs) are of great interest for future wearable electronics, but improvement in both high capacitance and high flexibility is still a challenge. Herein, we fabricate a high performance yarn asymmetric SC (ASC) using in situ prepared CuCo2O4 nanowires and polypyrrole (PPy) nanoparticles on the surface of a two-ply carbon nanotube (CNT) yarn. The parallel-shaped yarn ASC not only shows outstanding redox pseudocapacitance, including a high areal capacitance (59.55 mF cm-2), specific energy density (20 μW h cm-2) and power density (5...
November 23, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Xiaohui Wang, Jingsong Peng, Yuanyuan Zhang, Mingzhu Li, Eduardo Saiz, Antoni P Tomsia, Qunfeng Cheng
Graphene-based fibers synthesized under ambient temperature have not achieved excellent mechanical properties of high toughness or tensile strength compared with those synthesized by hydrothermal strategy or graphitization and annealing treatment. Inspired by the relationship between organic/inorganic hierarchical structure, interfacial interactions, and moderate growth temperature of natural nacre, we fabricate an ultratough graphene fiber via sequential toughening of hydrogen and ionic bonding through a wet-spinning method under ambient temperature...
November 30, 2018: ACS Nano
Yanqin Yang, Lingjie Xie, Zhen Wen, Chen Chen, Xiaoping Chen, Aiming Wei, Ping Cheng, Xinkai Xie, Xuhui Sun
To meet the urgent demand for rapid advancement of wearable electronics, challenges are still remained in developing wearable and sustainable power sources with simple fabrication and low cost. In this work, we demonstrate a flexible and coaxial fiber by fabricating one dimensional triboelectric nanogenerator (TENG) outside and supercapacitor (SC) inside, which can not only harvest mechanical energy but also store energy in all-in-one fiber. In such coaxial fiber, carbon fiber bundles are utilized as the electrode material for TENG as well as the active and electrode material for SC...
November 21, 2018: ACS Applied Materials & Interfaces
Shaikh Parwaiz, Owais Ahmed Malik, Debabrata Pradhan, Mohammad Mansoob Khan
This paper deals with the Cobalt-doped Ceria/reduced graphene oxide (Co-CeO2/rGO) nanocomposite as supercapacitor and modeling of its cyclic voltammetry behavior using Artificial Neural Network (ANN) and Random Forest Algorithm (RFA). A good agreement was found between experimental results and the predicted values generated by using ANN and RFA. Simulation results confirmed the accuracy of the models compared to measurements from supercapacitor module power-cycling. A comparison of best performance between ANN and RFA models shows that the ANN models performed better (value of coefficient of determination > 0...
November 20, 2018: Journal of Chemical Information and Modeling
Tae Yong Yun, Xinlin Li, Se Hyun Kim, Hong Chul Moon
Dual-function electrochromic supercapacitors (ECSs) indicating their real-time charge capacity in color are fabricated using tungsten trioxide (WO3) and Li-doped ion gels containing hydroquinone (HQ). The ECSs in this work can simultaneously serve as either electrochromic devices (ECDs) or supercapacitors, so the coloration/bleaching and charging/discharging characteristics are investigated between 0 and -1.5 V. At the optimal HQ concentration, a large transmittance contrast (~91 %), high coloration efficiency (~61...
November 20, 2018: ACS Applied Materials & Interfaces
Jukka Rinne, Jari Keskinen, Paul R Berger, Donald Lupo, Mikko Valkama
Techniques for wireless energy harvesting (WEH) are emerging as a fascinating set of solutions to extend the lifetime of energy-constrained wireless networks, and are commonly regarded as a key functional technique for almost perpetual communications. For example, with WEH technology, wireless devices are able to harvest energy from different light sources or Radio Frequency (RF) signals broadcast by ambient or dedicated wireless transmitters to support their operation and communications capabilities. WEH technology will have increasingly wider range of use in upcoming applications such as wireless sensor networks, Machine-to-Machine (M2M) communications, and the Internet of Things...
November 16, 2018: Sensors
Yinghui Shang, Junjie Wei, Chu Wu, Qigang Wang
Polymer gel electrolytes (PGEs) have been considered as one of the most promising candidates to solve safety and flexibility issues in wearable devices. To supply energy for the daily-used epidermal electronic systems, biaxial stretchability and temperature tolerance are essential for energy storage units. However, the limited choices of PGEs, including fragile poly(vinyl alcohol) and uniaxial stretchable polyacrylamide hydrogel, lag far behind the requirement of wearable supercapacitors. Herein, an adhesive organohydrogel with a water/ethylene glycol binary solvent is tailored as the electrolyte of an all-climate, biaxially stretchable pseudocapacitor...
November 30, 2018: ACS Applied Materials & Interfaces
Gaobo Lou, Yatao Wu, Xinqiang Zhu, Yingzhuo Lu, Shuai Yu, Chunhai Yang, Hao Chen, Cao Guan, Lu Li, Zhehong Shen
High cost, low capacitance, and complicated synthesis process are still the key limitations for carbon-negative materials to meet their industrial production and application in high-energy-density asymmetric supercapacitors (ASCs). In this work, we demonstrate the facile preparation of ultrahigh-surface-area free-standing carbon material from low-cost industrial carbon felt (CF) and its application for flexible supercapacitor electrode with outstanding performance. Through a simple freeze-drying-assisted activation method, the as-prepared activated CF (ACF) was endowed with satisfactory flexibility, ultrahigh specific surface area of 2109 m2 g-1 , good electric conductivity (311 S m-1 ), and excellent wettability to aqueous electrolyte...
November 28, 2018: ACS Applied Materials & Interfaces
Sheng Zhu, Yitan Li, Huiyu Zhu, Jiangfeng Ni, Yan Li
In this study, integrated plaster-like micro-supercapacitors based on medical adhesive tapes are fabricated by a simple pencil drawing process combined with a mild solution deposition of MnO2 . These solid micro-supercapacitors not only exhibit excellent stretchability, flexibility, and biocompatibility, but also possess outstanding electrochemical performances, such as exceptional rate capability and cycling stability. Hence they may act as skin-mountable and thin-film energy storage devices of high efficiency to power miniaturized and wearable electronic devices...
November 14, 2018: Small
Huifen Peng, Yuxiang Zhong, Xin Zhang, Yi He, Gongkai Wang
Transparent and flexible supercapacitors (TFSCs) are viable power sources for next-generation wearable electronics. The ingenious design of the transparent electrode determines the performance of TFSCs. A percolating film of a pillared graphene layer integrated with a silver nanowire network as the transparent electrode was prepared, by which TFSC devices exhibit a significantly improved performance contrastively. Under the condition of the same transmittance, about 27-72% improvement in the areal capacitance can be achieved...
November 27, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Yang Lu, Weixiao Wang, Yange Wang, Menglong Zhao, Jinru Lv, Yan Guo, Yingge Zhang, Rongjie Luo, Xianming Liu
Successful popularization of wearable energy storage devices lies in the exploitation of scalable fabrication technologies that are based on economically viable materials. Herein, we reveal that discarded cotton pads can be used as a cost-efficient substrate for the in situ polymerization of pyrrole and exhibited good mechanical flexibility, lightness, and high conductivity. To extend the applications of the resulting PPy-coated cotton pads (PCPs) to the supercapacitor field, a layer of MnO2 nanosheets was further decorated on the surface of PCPs (PCPs@MnO2) by a simple electrochemical deposition technique...
November 27, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Yun-Ting Chen, Cheng-Wen Ma, Chia-Ming Chang, Yao-Joe Yang
In this work, a flexible micro-supercapacitor with interdigital planar buckypaper electrodes is presented. A simple fabrication process involving vacuum filtration method and SU-8 molding techniques is proposed to fabricate in-plane interdigital buckypaper electrodes on a membrane filter substrate. The proposed process exhibits excellent flexibility for future integration of the micro-supercapacitors (micro-SC) with other electronic components. The device's maximum specific capacitance measured using cyclic voltammetry was 107...
May 16, 2018: Micromachines
Hsin-Ya Chiu, Chun-Pei Cho
MnO₂/N-containing graphene composites with various contents of Mn were fabricated and used as active materials for the electrodes of flexible solid-state asymmetric supercapacitors. By scanning electron microscopes (SEM), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectrometer (XPS), fourier-transform infrared spectroscopy (FTIR) and Raman spectra, the presence of MnO₂ and N-containing graphene was verified. The MnO₂ nanostructures decorated on the N-containing graphene were of α- and γ-mixed phases...
November 8, 2018: Nanomaterials
Hengzhao Yang
This paper investigates the impact of charge redistribution on supercapacitor charge capacity by experimentally estimating the charge capacity bounds. An analysis of a physics-based RC ladder circuit model for supercapacitors reveals the theoretical bounds and provides guidelines for designing experiments to estimate the bounds. The upper bound corresponds to a long time constant voltage charging process and the lower bound is established using a charging process with the largest possible current. Bounds of two types of supercapacitor charge capacity are estimated: the total charge stored in the supercapacitor that can be released during multiple discharging processes and the utilized charge delivered during one discharging action...
August 2018: IEEE transactions on power electronics
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