共查询到20条相似文献,搜索用时 31 毫秒
1.
A Low‐Cost,Self‐Standing NiCo2O4@CNT/CNT Multilayer Electrode for Flexible Asymmetric Solid‐State Supercapacitors 下载免费PDF全文
Peng Wu Shuang Cheng Minghai Yao Lufeng Yang Yuanyuan Zhu Peipei Liu Ou Xing Jun Zhou Mengkun Wang Haowei Luo Meilin Liu 《Advanced functional materials》2017,27(34)
The demand for a new generation of flexible, portable, and high‐capacity power sources increases rapidly with the development of advanced wearable electronic devices. Here we report a simple process for large‐scale fabrication of self‐standing composite film electrodes composed of NiCo2O4@carbon nanotube (CNT) for supercapacitors. Among all composite electrodes prepared, the one fired in air displays the best electrochemical behavior, achieving a specific capacitance of 1,590 F g?1 at 0.5 A g?1 while maintaining excellent stability. The NiCo2O4@CNT/CNT film electrodes are fabricated via stacking NiCo2O4@CNT and CNT alternately through vacuum filtration. Lightweight, flexible, and self‐standing film electrodes (≈24.3 µm thick) exhibit high volumetric capacitance of 873 F cm?3 (with an areal mass of 2.5 mg cm?2) at 0.5 A g?1. An all‐solid‐state asymmetric supercapacitor consists of a composite film electrode and a treated carbon cloth electrode has not only high energy density (≈27.6 Wh kg?1) at 0.55 kW kg?1 (including the weight of the two electrodes) but also excellent cycling stability (retaining ≈95% of the initial capacitance after 5000 cycles), demonstrating the potential for practical application in wearable devices. 相似文献
2.
Flexible All‐Solid‐State Supercapacitors of High Areal Capacitance Enabled by Porous Graphite Foams with Diverging Microtubes 下载免费PDF全文
Weigu Li Marshall C. Tekell Chang Liu Jacob A. Hethcock Donglei Fan 《Advanced functional materials》2018,28(29)
The practical applications of wearable electronics rely on the successful development of flexible and integrable energy devices with small footprints. This work reports a completely new type of graphite foam made of strategically created superstructures with covalently attached diverging microtubes, and their applications as electrode supports for binder‐free and additive‐free flexible supercapacitors. Because of the enhanced volumetric surface areas compared to conventional graphite foams, a high loading of pseudocapacitive materials (Mn3O4, 3.91 mg cm?2, 78 wt%) is achieved. The supercapacitors provide areal capacitances as high as 820 mF cm?2 at 1 mV s?1, while still maintaining high rate capability and 88% retention of capacitance after 3000 continuous charging and discharging cycles. When assembled as all‐solid‐state flexible symmetric supercapacitors, they offer one of the highest full‐cell capacitances (191 mF cm?2) among similar manganese oxide/graphene foams, and retain 80% capacitance after 1000 mechanical cycles. The potential of such flexible supercapacitors is also manifested by directly powering electric nanomotors that can trace along letters “U” and T,” which is the first demonstration of flexible supercapacitors for wireless/portable nanomanipulation systems. This work could inspire a new paradigm in designing and creating 3D porous micro/nanosuperstructures for an array of self‐powered electronic and nanomechanical applications. 相似文献
3.
Flexible Solid‐State Supercapacitors with Enhanced Performance from Hierarchically Graphene Nanocomposite Electrodes and Ionic Liquid Incorporated Gel Polymer Electrolyte 下载免费PDF全文
Lanxiang Feng Kai Wang Xiong Zhang Xianzhong Sun Chen Li Xingbo Ge Yanwei Ma 《Advanced functional materials》2018,28(4)
High energy density, durability, and flexibility of supercapacitors are required urgently for the next generation of wearable and portable electronic devices. Herein, a novel strategy is introduced to boost the energy density of flexible soild‐state supercapacitors via rational design of hierarchically graphene nanocomposite (GNC) electrode material and employing an ionic liquid gel polymer electrolyte. The hierarchical graphene nanocomposite consisting of graphene and polyaniline‐derived carbon is synthesized as an electrode material via a scalable process. The meso/microporous graphene nanocomposites exhibit a high specific capacitance of 176 F g?1 at 0.5 A g?1 in the ionic liquid 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIBF4) with a wide voltage window of 3.5 V, good rate capability of 80.7% in the range of 0.5–10 A g?1 and excellent stability over 10 000 cycles, which is attributed to the superior conductivity (7246 S m?1), and quite large specific surface area (2416 m2 g?1) as well as hierarchical meso/micropores distribution of the electrode materials. Furthermore, flexible solid‐state supercapacitor devices based on the GNC electrodes and gel polymer electrolyte film are assembled, which offer high specific capacitance of 180 F g?1 at 1 A g?1, large energy density of 75 Wh Kg?1, and remarkable flexible performance under consecutive bending conditions. 相似文献
4.
Self‐Powered Electronics by Integration of Flexible Solid‐State Graphene‐Based Supercapacitors with High Performance Perovskite Hybrid Solar Cells 下载免费PDF全文
Pengcheng Du Xiaowen Hu Chao Yi Huckleberry C. Liu Peng Liu Hao‐Li Zhang Xiong Gong 《Advanced functional materials》2015,25(16):2420-2427
To develop high‐capacitance flexible solid‐state supercapacitors and explore its application in self‐powered electronics is one of ongoing research topics. In this study, self‐stacked solvated graphene (SSG) films are reported that have been prepared by a facile vacuum filtration method as the free‐standing electrode for flexible solid‐state supercapacitors. The highly hydrated SSG films have low mass loading, high flexibility, and high electrical conductivity. The flexible solid‐state supercapacitors based on SSG films exhibit excellent capacitive characteristics with a high gravimetric specific capacitance of 245 F g?1 and good cycling stability of 10 000 cycles. Furthermore, the flexible solid‐state supercapacitors are integrated with high performance perovskite hybrid solar cells (pero‐HSCs) to build self‐powered electronics. It is found that the solid‐state supercapacitors can be charged by pero‐HSCs and discharged from 0.75 V. These results demonstrate that the self‐powered electronics by integration of the flexible solid‐state supercapacitors with pero‐HSCs have great potential applications in storage of solar energy and in flexible electronics, such as portable and wearable personal devices. 相似文献
5.
Novel Core–Shell FeOF/Ni(OH)2 Hierarchical Nanostructure for All‐Solid‐State Flexible Supercapacitors with Enhanced Performance 下载免费PDF全文
Mengqiao Wang Zhaoqiang Li Chengxiang Wang Ruizheng Zhao Caixia Li Dexiang Guo Luyuan Zhang Longwei Yin 《Advanced functional materials》2017,27(31)
Well‐controlled core–shell hierarchical nanostructures based on oxyfluoride and hydroxide are for the first time rationally designed and synthesized via a simple solvothermal and chemical precipitation route, in which FeOF nanorod acts as core and porous Ni(OH)2 nanosheets as shell. When evaluated as electrodes for supercapacitors, a high specific capacitance of 1452 F g?1 can be obtained at a current density of 1 A g?1. Even as the current density increases to 10 A g?1, the core–shell hybrid still reserves a noticeable capacitance of 1060 F g?1, showing an excellent rate capacity. Furthermore, all‐solid‐state flexible asymmetric supercapacitor based on the FeOF/Ni(OH)2 hybrid as a positive electrode and activated carbon as a negative electrode shows high power density, high energy density, and long cycling lifespan. The excellent electrochemical performance of the FeOF/Ni(OH)2 core–shell hybrid is ascribed to the unique microstructure and synergistic effects. FeOF nanorod from FeF3 by partial substitution of fluorine with oxygen behaves as a low intrinsic resistance, thus facilitating charge transfer processes. While the hierarchical Ni(OH)2 nanosheets with large surface area provide enough active sites for redox chemical reactions, leading to greatly enhanced electrochemical activity. The well‐controllable oxyfluoride/hydroxide hybrid is inspiring, opening up a new way to design new electrodes for next‐generation all‐solid‐state supercapacitors. 相似文献
6.
Zhiyuan Chen Yongrui Yang Zhihao Ma Tao Zhu Lei Liu Jie Zheng Xiong Gong 《Advanced functional materials》2019,29(38)
All‐solid‐state flexible asymmetric supercapacitors (ASCs) are developed by utilization of graphene nanoribbon (GNR)/Co0.85Se composites as the positive electrode, GNR/Bi2Se3 composites as the negative electrode, and polymer‐grafted‐graphene oxide membranes as solid‐state electrolytes. Both GNR/Co0.85Se and GNR/Bi2Se3 composite electrodes are developed by a facile one‐step hydrothermal growth method from graphene oxide nanoribbons as the nucleation framework. The GNR/Co0.85Se composite electrode exhibits a specific capacity of 76.4 mAh g?1 at a current density of 1 A g?1 and the GNR/Bi2Se3 composite electrode exhibits a specific capacity of 100.2 mAh g?1 at a current density of 0.5 A g?1. Moreover, the stretchable membrane solid‐state electrolytes exhibit superior ionic conductivity of 108.7 mS cm?1. As a result, the flexible ASCs demonstrate an operating voltage of 1.6 V, an energy density of 30.9 Wh kg?1 at the power density of 559 W kg?1, and excellent cycling stability with 89% capacitance retention after 5000 cycles. All these results demonstrate that this study provides a simple, scalable, and efficient approach to fabricate high performance flexible all‐solid‐state ASCs for energy storage. 相似文献
7.
Zhen Xu Fei Xie Jing Wang Heather Au Mike Tebyetekerwa Zhenyu Guo Shengyuan Yang Yong‐Sheng Hu Maria‐Magdalena Titirici 《Advanced functional materials》2019,29(39)
Na‐ion hybrid capacitors consisting of battery‐type anodes and capacitor‐style cathodes are attracting increasing attention on account of the abundance of sodium‐based resources as well as the potential to bridge the gap between batteries (high energy) and supercapacitors (high power). Herein, hierarchically structured carbon materials inspired by multiscale building units of cellulose from nature are assembled with cellulose‐based gel electrolytes into Na‐ion capacitors. Nonporous hard carbon anodes are obtained through the direct thermal pyrolysis of cellulose nanocrystals. Nitrogen‐doped carbon cathodes with a coral‐like hierarchically porous architecture are prepared via hydrothermal carbonization and activation of cellulose microfibrils. The reversible charge capacity of the anode is 256.9 mAh g?1 when operating at 0.1 A g?1 from 0 to 1.5 V versus Na+/Na, and the discharge capacitance of cathodes tested within 1.5 to 4.2 V versus Na+/Na is 212.4 F g?1 at 0.1 A g?1. Utilizing Na+ and ClO4? as charge carriers, the energy density of the full Na‐ion capacitor with two asymmetric carbon electrodes can reach 181 Wh kg?1 at 250 W kg?1, which is one of the highest energy devices reported until now. Combined with macrocellulose‐based gel electrolytes, all‐cellulose‐based quasi‐solid‐state devices are demonstrated possessing additional advantages in terms of overall sustainability. 相似文献
8.
Flexible Asymmetric Supercapacitor Based on Structure‐Optimized Mn3O4/Reduced Graphene Oxide Nanohybrid Paper with High Energy and Power Density 下载免费PDF全文
Yating Hu Cao Guan Guangxue Feng Qingqing Ke Xiaolei Huang John Wang 《Advanced functional materials》2015,25(47):7291-7299
A highly flexible Mn3O4/reduced graphene oxide (rGO) nanohybrid paper with high electrical conductivity and high mass loading of Mn3O4 nanofibers (0.71 g cm?3) is developed via a facile gel formation and electrochemical reduction process, which is low‐cost, environmental friendly, and easy to scale up. Confined Mn3O4 nanofibers are well dispersed within the rGO sheets, which demonstrate to be a promising cathode material for flexible asymmetric supercapacitors (ASCs). When coupled with an electrochemically reduced rGO paper as the anode, a flexible ASC device, based on the Mn3O4/rGO nanohybrid paper as the cathode, is assembled; and it demonstrates remarkable electrochemical performance: a high volumetric capacitance of 54.6 F cm?3 (546.05 mF cm?2), and remarkable volumetric energy and power density (0.0055 Wh cm?3 and 10.95 W cm?3) being achieved with excellent cycling ability. The nanohybrid paper shows great improvement for flexible energy devices in terms of electrochemical properties. 相似文献
9.
Rationally Engineered Electrodes for a High‐Performance Solid‐State Cable‐Type Supercapacitor 下载免费PDF全文
Ranjith Vellacheri Huaping Zhao Mike Mühlstädt Ahmed Al‐Haddad Klaus D. Jandt Yong Lei 《Advanced functional materials》2017,27(18)
Wire‐shaped electrodes for solid‐state cable‐type supercapacitors (SSCTS) with high device capacitance and ultrahigh rate capability are prepared by depositing poly(3,4‐ethylenedioxythiophene) onto self‐doped TiO2 nanotubes (D‐TiO2) aligned on Ti wire via a well‐controlled electrochemical process. The large surface area, short ion diffusion path, and high electrical conductivity of these rationally engineered electrodes all contribute to the energy storage performance of SSCTS. The cyclic voltammetric studies show the good energy storage ability of the SSCTS even at an ultrahigh scan rate of 1000 V s?1, which reveals the excellent instantaneous power characteristics of the device. The capacitance of 1.1 V SSCTS obtained from the charge–discharge measurements is 208.36 µF cm?1 at a discharge current of 100 µA cm?1 and 152.36 µF cm?1 at a discharge current of 2000 µA cm?1, respectively, indicating the ultrahigh rate capability. Furthermore, the SSCTS shows superior cyclic stability during long‐term (20 000 cycles) cycling, and also maintains excellent performance when it is subjected to bending and succeeding straightening process. 相似文献
10.
High‐Performance Wearable Micro‐Supercapacitors Based on Microfluidic‐Directed Nitrogen‐Doped Graphene Fiber Electrodes 下载免费PDF全文
Guan Wu Pengfeng Tan Xingjiang Wu Lu Peng Hengyang Cheng Cai‐Feng Wang Wei Chen Ziyi Yu Su Chen 《Advanced functional materials》2017,27(36)
Fiber‐shaped micro‐supercapacitors (micro‐SCs) have attracted enormous interest in wearable electronics due to high flexibility and weavability. However, they usually present a low energy density because of inhomogeneity and less pores. Here, we demonstrate a microfluidic‐directed strategy to synthesize homogeneous nitrogen‐doped porous graphene fibers. The porous fibers‐based micro‐SCs utilize solid‐state phosphoric acid/polyvinyl alcohol (H3PO4/PVA) and 1‐ethyl‐3‐methylimidazolium tetrafluoroborate/poly(vinylidenefluoride‐co‐hexafluoropropylene) (EMIBF4/PVDF‐HFP) electrolytes, which show significant improvements in electrochemical performances. Ultralarge capacitance (1132 mF cm?2), high cycling‐stability, and long‐term bending‐durability are achieved based on H3PO4/PVA. Additionally, high energy densities of 95.7–46.9 µWh cm?2 at power densities of 1.5–15 W cm?2 are obtained in EMIBF4/PVDF‐HFP. The key to higher performances stems from microfluidic‐controlled fibers with a uniformly porous network, large specific surface area (388.6 m2 g?1), optimal pyridinic nitrogen (2.44%), and high electric conductivity (30785 S m?1) for faster ion diffusion and flooding accommodation. By taking advantage of these remarkable merits, this study integrates micro‐SCs into flexible and fabric substrates to power audio–visual electronics. The main aim is to clarify the important role of microfluidic techniques toward the architecture of electrodes and promote development of wearable electronics. 相似文献
11.
Carbon‐Stabilized High‐Capacity Ferroferric Oxide Nanorod Array for Flexible Solid‐State Alkaline Battery–Supercapacitor Hybrid Device with High Environmental Suitability 下载免费PDF全文
Ruizhi Li Yimeng Wang Cheng Zhou Chong Wang Xin Ba Yuanyuan Li Xintang Huang Jinping Liu 《Advanced functional materials》2015,25(33):5384-5394
Iron oxides are promising to be utilized in rechargeable alkaline battery with high capacity upon complete redox reaction (Fe3+ Fe0). However, their practical application has been hampered by the poor structural stability during cycling, presenting a challenge that is particularly huge when binder‐free electrode is employed. This paper proposes a “carbon shell‐protection” solution and reports on a ferroferric oxide–carbon (Fe3O4–C) binder‐free nanorod array anode exhibiting much improved cyclic stability (from only hundreds of times to >5000 times), excellent rate performance, and a high capacity of ≈7776.36 C cm?3 (≈0.4278 C cm?2; 247.5 mAh g?1, 71.4% of the theoretical value) in alkaline electrolyte. Furthermore, by pairing with a capacitive carbon nanotubes (CNTs) film cathode, a unique flexible solid‐state rechargeable alkaline battery‐supercapacitor hybrid device (≈360 μm thickness) is assembled. It delivers high energy and power densities (1.56 mWh cm?3; 0.48 W cm?3/≈4.8 s charging), surpassing many recently reported flexible supercapacitors. The highest energy density value even approaches that of Li thin‐film batteries and is about several times that of the commercial 5.5 V/100 mF supercapacitor. In particular, the hybrid device still maintains good electrochemical attributes in cases of substantially bending, high mechanical pressure, and elevated temperature (up to 80 °C), demonstrating high environmental suitability. 相似文献
12.
Prolifera‐Green‐Tide as Sustainable Source for Carbonaceous Aerogels with Hierarchical Pore to Achieve Multiple Energy Storage 下载免费PDF全文
Jinfeng Cui Yunlong Xi Shuai Chen Daohao Li Xilin She Jin Sun Wei Han Dongjiang Yang Shaojun Guo 《Advanced functional materials》2016,26(46):8487-8495
The increasing demand for efficient energy storage and conversion devices has aroused great interest in designing advanced materials with high specific surface areas, multiple holes, and good conductivity. Here, we report a new method for fabricating a hierarchical porous carbonaceous aerogel (HPCA) from renewable seaweed aerogel. The HPCA possesses high specific surface area of 2200 m2 g?1 and multilevel micro/meso/macropore structures. These important features make HPCA exhibit a reversible lithium storage capacity of 827.1 mAh g?1 at the current density of 0.1 A g?1, which is the highest capacity for all the previously reported nonheteroatom‐doped carbon nanomaterials. It also shows high specific capacitance and excellent rate performance for electric double layer capacitors (260.6 F g?1 at 1 A g?1 and 190.0 F g?1 at 50 A g?1), and long cycle life with 91.7% capacitance retention after 10 000 cycles at 10 A g?1. The HPCA also can be used as support to assemble Co3O4 nanowires (Co3O4@HPCA) for constructing a high performance pseudocapacitor with the maximum specific capacitance of 1167.6 F g?1 at the current density of 1 A g?1. The present work highlights the first example in using prolifera‐green‐tide as a sustainable source for developing advanced carbon porous aerogels to achieve multiple energy storage. 相似文献
13.
Three‐Dimensional Co3O4@MnO2 Hierarchical Nanoneedle Arrays: Morphology Control and Electrochemical Energy Storage 下载免费PDF全文
Dezhi Kong Jingshan Luo Yanlong Wang Weina Ren Ting Yu Yongsong Luo Yaping Yang Chuanwei Cheng 《Advanced functional materials》2014,24(24):3815-3826
In this paper, a highly ordered three‐dimensional Co3O4@MnO2 hierarchical porous nanoneedle array on nickel foam is fabricated by a facile, stepwise hydrothermal approach. The morphologies evolution of Co3O4 and Co3O4@MnO2 nanostructures upon reaction times and growth temperature are investigated in detail. Moreover, the as‐prepared Co3O4@MnO2 hierarchical structures are investigated as anodes for both supercapacitors and Li‐ion batteries. When used for supercapacitors, excellent electrochemical performances such as high specific capacitances of 932.8 F g?1 at a scan rate of 10 mV s?1 and 1693.2 F g?1 at a current density of 1 A g?1 as well as long‐term cycling stability and high energy density (66.2 W h kg?1 at a power density of 0.25 kW kg?1), which are better than that of the individual component of Co3O4 nanoneedles and MnO2 nanosheets, are obtained. The Co3O4@MnO2 NAs are also tested as anode material for LIBs for the first time, which presents an improved performance with high reversible capacity of 1060 mA h g?1 at a rate of 120 mA g?1, good cycling stability, and rate capability. 相似文献
14.
Molecular Design of Mesoporous NiCo2O4 and NiCo2S4 with Sub‐Micrometer‐Polyhedron Architectures for Efficient Pseudocapacitive Energy Storage 下载免费PDF全文
Yu Liu Zhenbin Wang Yijun Zhong Moses Tade Wei Zhou Zongping Shao 《Advanced functional materials》2017,27(28)
Spinel‐type NiCo2O4 (NCO) and NiCo2S4 (NCS) polyhedron architectures with sizes of 500–600 nm and rich mesopores with diameters of 1–2 nm are prepared facilely by the molecular design of Ni and Co into polyhedron‐shaped zeolitic imidazolate frameworks as solid precursors. Both as‐prepared NCO and NCS nanostructures exhibit excellent pseudocapacitance and stability as electrodes in supercapacitors. In particular, the exchange of O2? in the lattice of NCO with S2? obviously improves the electrochemical performance. NCS shows a highly attractive capacitance of 1296 F g?1 at a current density of 1 A g?1, ultrahigh rate capability with 93.2% capacitance retention at 10 A g?1, and excellent cycling stability with a capacitance retention of 94.5% after cycling at 1 A g?1 for 6000 times. The asymmetric supercapacitor with an NCS negative electrode and an active carbon positive electrode delivers a very attractive energy density of 44.8 Wh kg?1 at power density 794.5 W kg?1, and a favorable energy density of 37.7 Wh kg?1 is still achieved at a high power density of 7981.1 W kg?1. The specific mesoporous polyhedron architecture contributes significantly to the outstanding electrochemical performances of both NCO and NCS for capacitive energy storage. 相似文献
15.
Yusen Zhao Yousif Alsaid Bowen Yao Yucheng Zhang Bozhen Zhang Neel Bhuskute Shuwang Wu Ximin He 《Advanced functional materials》2020,30(10)
Oriented microstructures are widely found in various biological systems for multiple functions. Such anisotropic structures provide low tortuosity and sufficient surface area, desirable for the design of high‐performance energy storage devices. Despite significant efforts to develop supercapacitors with aligned morphology, challenges remain due to the predefined pore sizes, limited mechanical flexibility, and low mass loading. Herein, a wood‐inspired flexible all‐solid‐state hydrogel supercapacitor is demonstrated by morphologically tuning the aligned hydrogel matrix toward high electrode‐materials loading and high areal capacitance. The highly aligned matrix exhibits broad morphological tunability (47–12 µm), mechanical flexibility (0°–180° bending), and uniform polypyrrole loading up to 7 mm thick matrix. After being assembled into a solid‐state supercapacitor, the areal capacitance reaches 831 mF cm?2 for the 12 µm matrix, which is 259% times of the 47 µm matrix and 403% times of nonaligned matrix. The supercapacitor also exhibits a high energy density of 73.8 µWh cm?2, power density of 4960 µW cm?2, capacitance retention of 86.5% after 1000 cycles, and bending stability of 95% after 5000 cycles. The principle to structurally design the oriented matrices for high electrode material loading opens up the possibility for advanced energy storage applications. 相似文献
16.
Runsheng Gao Jie Tang Xiaoliang Yu Shiqi Lin Kun Zhang Lu‐Chang Qin 《Advanced functional materials》2020,30(27)
Silicon‐based materials have shown great potential and been widely studied in various fields. Unlike its unparalleled theoretical capacity as anodes for batteries, few investigations have been reported on silicon‐based materials for applications in supercapacitors. Here, an electrode composed of layered silicon‐based nanosheets, obtained through oxidation and exfoliation, for a supercapacitor operated up to 4 V is reported. These silicon‐based nanosheets show an areal specific capacitance of 4.43 mF cm?2 at 10 mV s?1 while still retaining a specific capacitance of 834 µF cm?2 even at an ultrahigh scan rate of 50 000 mV s?1. The volumetric energy and power density of the supercapacitor are 7.65 mWh cm?3 and 9312 mW cm?3, respectively, and the electrode can operate for 12000 cycles in a potential window of 4 V at 2 A g?1, while retaining 90.6% capacitance. These results indicate that the silicon‐based nanosheets can be a competitive candidate as the supercapacitor electrode material. 相似文献
17.
Yue Dong Su Zhang Xian Du Song Hong Shengna Zhao Yaxin Chen Xiaohong Chen Huaihe Song 《Advanced functional materials》2019,29(24)
Improving the capacitance of carbon materials for supercapacitors without sacrificing their rate performance, especially volumetric capacitance at high mass loadings, is a big challenge because of the limited assessable surface area and sluggish electrochemical kinetics of the pseudocapacitive reactions. Here, it is demonstrated that “self‐doping” defects in carbon materials can contribute to additional capacitance with an electrical double‐layer behavior, thus promoting a significant increase in the specific capacitance. As an exemplification, a novel defect‐enriched graphene block with a low specific surface area of 29.7 m2 g?1 and high packing density of 0.917 g cm?3 performs high gravimetric, volumetric, and areal capacitances of 235 F g?1, 215 F cm?3, and 3.95 F cm?2 (mass loading of 22 mg cm?2) at 1 A g?1, respectively, as well as outstanding rate performance. The resulting specific areal capacitance reaches an ultrahigh value of 7.91 F m?2 including a “self‐doping” defect contribution of 4.81 F m?2, which is dramatically higher than the theoretical capacitance of graphene (0.21 F m?2) and most of the reported carbon‐based materials. Therefore, the defect engineering route broadens the avenue to further improve the capacitive performance of carbon materials, especially for compact energy storage under limited surface areas. 相似文献
18.
Controlled Incorporation of Ni(OH)2 Nanoplates Into Flowerlike MoS2 Nanosheets for Flexible All‐Solid‐State Supercapacitors 下载免费PDF全文
Chunxue Hao Fusheng Wen Jianyong Xiang Limin Wang Hang Hou Zhibin Su Wentao Hu Zhongyuan Liu 《Advanced functional materials》2014,24(42):6700-6707
In this work, self‐supporting three‐dimensional hierarchical nanostructured MoS2@Ni(OH)2 nanocomposites are synthesized via a facile single‐mode microwave hydrothermal technique. The fabricated MoS2@Ni(OH)2 nanocomposites for supercapacitors in aqueous electrolyte exhibit higher specific capacitance and better cyclic stability than those of MoS2 and Ni(OH)2 due to the pronounced synergistic effect between MoS2 and Ni(OH)2. Further, the flexible all‐solid‐state supercapcitor is readily constructed by composing the PVA/KOH gel electrolyte in between two MoS2@Ni(OH)2 electrodes on the flexible PET substrates. The resulting supercapacitors can operate at high rate up to 1000 V/s, have excellent long‐life cycling stability, retaining 94.2% of the initial capacitance after 9000 cycles, and mechanical flexibility during extreme bending, respectively. Thereby, the MoS2@Ni(OH)2 nanocomposites are a promising electrode materials for flexible long‐life cycling all‐solid‐sate supercapacitors. 相似文献
19.
Oxygen‐Deficient Bismuth Oxide/Graphene of Ultrahigh Capacitance as Advanced Flexible Anode for Asymmetric Supercapacitors 下载免费PDF全文
Rong Liu Lina Ma Gudan Niu Xiaolong Li Enyuan Li Yang Bai Guohui Yuan 《Advanced functional materials》2017,27(29)
Oxygen‐deficient bismuth oxide (r‐Bi2O3)/graphene (GN) is designed, fabricated, and demonstrated via a facile solvothermal and subsequent solution reduction method. The ultrafine network bacterial cellulose (BC) as substrate for r‐Bi2O3/GN exhibits high flexibility, remarkable tensile strength (55.1 MPa), and large mass loading of 9.8 mg cm?2. The flexible r‐Bi2O3/GN/BC anode delivers appreciable areal capacitance (6675 mF cm?2 at 1 mA cm?2) coupled with good rate capability (3750 mF cm?2 at 50 mA cm?2). In addition, oxygen vacancies have great influence on the capacitive performance of Bi2O3, delivering significantly improved capacitive values than the untreated Bi2O3 flexible electrode, and ultrahigh gravimetric capacitance of 1137 F g?1 (based on the mass of r‐Bi2O3) can be obtained, achieving 83% of the theoretical value (1370 F g?1). Flexible asymmetric supercapacitor is fabricated with r‐Bi2O3/GN/BC and Co3O4/GN/BC paper as the negative and positive electrodes, respectively. The operation voltage is expanded to 1.6 V, revealing a maximum areal energy density of 0.449 mWh cm?2 (7.74 mWh cm?3) and an areal power density of 40 mW cm?2 (690 mW cm?3). Therefore, this flexible anode with excellent electrochemical performance and high mechanical properties shows great potential in the field of flexible energy storage devices. 相似文献
20.
Sebastiano Bellani Elisa Petroni Antonio Esau Del Rio Castillo Nicola Curreli Beatriz Martín‐García Reinier Oropesa‐Nuez Mirko Prato Francesco Bonaccorso 《Advanced functional materials》2019,29(14)
The miniaturization of energy storage units is pivotal for the development of next‐generation portable electronic devices. Micro‐supercapacitors (MSCs) hold great potential to work as on‐chip micro‐power sources and energy storage units complementing batteries and energy harvester systems. Scalable production of supercapacitor materials with cost‐effective and high‐throughput processing methods is crucial for the widespread application of MSCs. Here, wet‐jet milling exfoliation of graphite is reported to scale up the production of graphene as a supercapacitor material. The formulation of aqueous/alcohol‐based graphene inks allows metal‐free, flexible MSCs to be screen‐printed. These MSCs exhibit areal capacitance (Careal) values up to 1.324 mF cm?2 (5.296 mF cm?2 for a single electrode), corresponding to an outstanding volumetric capacitance (Cvol) of 0.490 F cm?3 (1.961 F cm?3 for a single electrode). The screen‐printed MSCs can operate up to a power density above 20 mW cm?2 at an energy density of 0.064 µWh cm?2. The devices exhibit excellent cycling stability over charge–discharge cycling (10 000 cycles), bending cycling (100 cycles at a bending radius of 1 cm) and folding (up to angles of 180°). Moreover, ethylene vinyl acetate‐encapsulated MSCs retain their electrochemical properties after a home‐laundry cycle, providing waterproof and washable properties for prospective application in wearable electronics. 相似文献