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Journal ArticleDOI: 10.1039/D0TA09882E

Design of unique porous carbons with double support structure: toward overall performance by employing bidirectional anchoring strategy

02 Mar 2021-Journal of Materials Chemistry (The Royal Society of Chemistry)-Vol. 9, Iss: 8, pp 5075-5085
Abstract: Supercapacitors are highly attractive in the large-scale energy storage field, but the “trade-off” between the gravimetric capacitance and the volume and area specific capacitance greatly affects their further development. In this work, we developed coralloid-like porous carbon sheets (CPCS) with double support structure via a bidirectional anchoring strategy, exhibiting ultra-low specific surface area (26.95 m2 g−1) and moderate packing density (0.75 g cm−3). In the meantime, the proposed dual-anchor structure model made the interior “self-doping” defects and the exterior “foreign-doping” defects fully exposed, which is seldom obtained by other artificial methods. Based on this, it delivered a superior overall performance in gravimetric, volumetric, and areal capacitances (308.89 F g−1, 231.67 F cm−3, and 1146 μF cm−2) and stable cyclability (10 000 cycles), which is the highest capacitance reported for polyacrylonitrile-based hard carbon without chemical/physical activation. Considering the low-energy and innovative synthesis route, our work may shed some light on developing advanced carbons promising for supercapacitors.

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Topics: Capacitance (52%), Supercapacitor (52%)
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5 results found


Journal ArticleDOI: 10.1016/J.COMPOSITESB.2021.109256
Chengwei Ye1, Lan Xu1Institutions (1)
Abstract: In view of the respective advantages of electrical double layer capacitance (EDLC) and pseudocapacitance, the development of electrode materials with dual energy storage mechanisms (EDLC and pseudocapacitance) will play a significant role in maximizing the overall capacitance performance. In this paper, the core-shell fibers with dense zeolite imidazole framework (ZIF) coating were synthesized on the electrospun composite nanofiber substrate by a rapid in-situ growth strategy. After pyrolysis of ZIFs(shell)@PAN/PVP(core) fibers, heteroatom-doped porous carbon fiber materials with high specific surface area (410.55 m2 g-1) were obtained. It not only had a layered porous structure, but also fully exposed the doped active sites, which made it have the advantages of EDLC and pseudocapacitance. As expected, the prepared porous carbon materials doped with rich heteroatom, as supercapacitor electrode materials, exhibited large specific capacitances of 492.7 F g−1 at a current density of 1 A g−1 and 406.4 F g−1 at 10 A g−1. After 5000 cycles of galvanostatic charge-discharge at 10 A g−1, its capacitance retention rate was as high as 98.65%, showing excellent charge storage performance and good cycle stability. Therefore, this work presents an effective strategy for the design and preparation of supercapacitor electrode materials with dual energy storage mechanisms.

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Topics: Pseudocapacitance (59%), Supercapacitor (56%), Fiber (52%) ... read more

1 Citations


Journal ArticleDOI: 10.1039/D1NR02765D
Chenyang Zhao1, Chengyao Zhao2, Qi Liu2, Xiaohui Liu2  +5 moreInstitutions (2)
29 Jul 2021-Nanoscale
Abstract: A small size effect could be conducive to enhancing the electrochemical performance, while the mechanism by which they also increase the capacitance for carbon electrode materials has not been established. Here, ultrasmall polyacrylonitrile particles with controllable sizes are supported on poly(ionic liquid)s microspheres (PILMs/PAN) by epitaxial polymerization growth strategy. Unlike traditional subtraction formulas in developing a porous architecture, we report on the synthesis of creating numerous micro/mesopores in carbon materials by addition theorem, and thus making for the perfection of packing density, which has not been reported yet. As an example, PILMC/PAN-L with a well-balanced specific surface area of 875.38 m2 g−1 and packing density of 1.05 g cm−3 demonstrated gravimetric and volumetric capacitances of 309 F g−1 and 324.45 F cm−3 at 0.5 A g−1, showing good rate performance and stable cyclability. Moreover, the underlying mechanism is thoroughly developed using multiple electrochemical methods. On this basis, this work would afford avenues to further enhancing the electrochemical performance, especially in exploring advanced carbon materials.

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Topics: Supercapacitor (51%)

1 Citations


Journal ArticleDOI: 10.1016/J.JPOWSOUR.2021.230621
Qi Liu1, Weiqun Gong1, Shengnan Li1, Chenyang Zhao2  +5 moreInstitutions (2)
Abstract: Carbon-based supercapacitors with outstanding electrochemical performances are strongly desired for the development of portable and wearable electronics. From the free radical engineering point of view, this study innovatively developed carbon/carbon gradient-structured microspheres (CCGMs) by the strategy of “third-order graduation polymerization” and “dynamic radical oxidation”. Compared to conventional hybrid materials, for the first time, the gradient structure is proved to be extremely beneficial for improving the capacitive performance. Benefiting its gradient-structured advantages, the CCGMs exhibited “three-ultrahigh” performance with gravimetric, volumetric, and areal capacitances of 408.23 F g−1, 741.11 F cm−3, and 4390 μF cm−2, respectively. In addition, the assembled all-solids-state micro-supercapacitors delivered superior volumetric and areal specific capacitances (7.704 F cm−3 and 9.245 mF cm−2 at 5 μA cm−2), excellent life-span (100% after 12000 cycles), excellent volumetric and areal energy densities (1070 mWh cm−3 and 1284 μWh cm−2). This work paves a new way to develop unique carbon composites for high‐performance energy storage devices.

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Topics: Supercapacitor (53%)

1 Citations


Journal ArticleDOI: 10.1021/ACS.JPCC.0C11035
Abstract: Supercapacitors have presented promising results in energy storage until now, making them a possible candidate for becoming a mainstream rechargeable power source, which could be easily integrated ...

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Topics: Energy storage (56%), Supercapacitor (50%)

Journal ArticleDOI: 10.1016/J.APSUSC.2021.150937
Ning Liu1, Xiangyi Zhang1, Enhui He1, Wenjun Zhou1  +2 moreInstitutions (1)
Abstract: Transition metal sulfides with high theoretical specific capacitance are widely used as electrode materials for supercapacitors, but their poor cycling stability and energy density prevent them from meeting the needs of practical applications. To solve this problem, it is urgent to design an electrode material with excellent electrochemical performance. Here, polyacrylonitrile polymer layer-modified Co3S4 microspheres are anchored on a Ni foam substrate and then subjected to high-temperature carbonization to prepare a Carbon@Co3S4/Ni3S2/NF core–shell composite electrode. Its areal specific capacitance reached 1716 mF cm−2 at a current density of 1 mA cm−2 and 1128.9 mF cm−2 at 20 mA cm−2. Compared with the Co3S4/Ni3S2/NF electrode, its cycling stability is significantly improved, and the capacitance retention rate reaches 109% after 10,000 cycles. In addition, the assembled symmetrical supercapacitor achieves a higher energy density of 11.15 mWh cm−3 at a power density of 600 mW cm−3 and excellent cycling performance (approximately 90.3% capacitance retention over 5000 cycles). More importantly, this study illustrates a new method for improving the cycling stability and specific capacitance of transition metal sulfides, which provides the possibility of further practical application of the materials.

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Topics: Capacitance (56%), Supercapacitor (54%), Electrode (50%)
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55 results found


Open accessJournal ArticleDOI: 10.1126/SCIENCE.AAB3798
Tianquan Lin1, I-Wei Chen2, Fengxin Liu1, Chongyin Yang1  +4 moreInstitutions (3)
18 Dec 2015-Science
Abstract: Carbon-based supercapacitors can provide high electrical power, but they do not have sufficient energy density to directly compete with batteries. We found that a nitrogen-doped ordered mesoporous few-layer carbon has a capacitance of 855 farads per gram in aqueous electrolytes and can be bipolarly charged or discharged at a fast, carbon-like speed. The improvement mostly stems from robust redox reactions at nitrogen-associated defects that transform inert graphene-like layered carbon into an electrochemically active substance without affecting its electric conductivity. These bipolar aqueous-electrolyte electrochemical cells offer power densities and lifetimes similar to those of carbon-based supercapacitors and can store a specific energy of 41 watt-hours per kilogram (19.5 watt-hours per liter).

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Topics: Supercapacitor (59%), Carbon (55%), Electrochemical cell (53%) ... read more

1,425 Citations


Open accessJournal ArticleDOI: 10.1039/C3EE41444B
Abstract: Heteroatom doped carbon materials represent one of the most prominent families of materials that are used in energy related applications, such as fuel cells, batteries, hydrogen storage or supercapacitors. While doping carbons with nitrogen atoms has experienced great progress throughout the past decades and yielded promising material concepts, also other doping candidates have gained the researchers' interest in the last few years. Boron is already relatively widely studied, and as its electronic situation is contrary to the one of nitrogen, codoping carbons with both heteroatoms can probably create synergistic effects. Sulphur and phosphorus have just recently entered the world of carbon synthesis, but already the first studies published prove their potential, especially as electrocatalysts in the cathodic compartment of fuel cells. Due to their size and their electronegativity being lower than those of carbon, structural distortions and changes of the charge densities are induced in the carbon materials. This article is to give a state of the art update on the most recent developments concerning the advanced heteroatom doping of carbon that goes beyond nitrogen. Doped carbon materials and their applications in energy devices are discussed with respect to their boron-, sulphur- and phosphorus-doping.

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Topics: Heteroatom (63%), Carbon (52%), Hydrogen storage (51%)

1,242 Citations


Open accessJournal ArticleDOI: 10.1038/NENERGY.2016.70
27 May 2016-Nature Energy
Abstract: Supercapacitors are electrochemical energy storage devices that operate on the simple mechanism of adsorption of ions from an electrolyte on a high-surface-area electrode. Over the past decade, the performance of supercapacitors has greatly improved, as electrode materials have been tuned at the nanoscale and electrolytes have gained an active role, enabling more efficient storage mechanisms. In porous carbon materials with subnanometre pores, the desolvation of the ions leads to surprisingly high capacitances. Oxide materials store charge by surface redox reactions, leading to the pseudocapacitive effect. Understanding the physical mechanisms underlying charge storage in these materials is important for further development of supercapacitors. Here we review recent progress, from both in situ experiments and advanced simulation techniques, in understanding the charge storage mechanism in carbon- and oxide-based supercapacitors. We also discuss the challenges that still need to be addressed for building better supercapacitors.

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1,160 Citations


Journal ArticleDOI: 10.1016/0013-4686(90)85068-X
Abstract: The dependence of the voltammetric surface charge q* on solution pH and potential scan rate has been investigated using a set of RuO2 electrodes prepared by thermal decomposition of RuCl3 at temperatures in the range 300–500°C The systematically higher charge in KOH than in HClO4 in the same potential range (vs rhe) is attributed to the stabilization of higher oxidation states of surface Ru atoms in the alkaline environment The variation of q* with v, the potential scan rate, is shown to be linearizable as a function of v 1 2 It is thus possible to extrapolate the values of q* to v=0 and v=∞, respectively The extrapolation enables an “inner” surface to be discriminated from an “outer” surface The former is pointed out to be composed by the regions of difficult accessibility for the proton-donating species assisting the surface redox reactions Reasons why the “screened” surface appears to be higher in alkaline than in acid solutions, are discussed It is stressed that only working with a set of RuO2 electrodes prepared at different temperatures it is possible to discover meaningful correlations

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Topics: Surface charge (56%), Active surface (53%)

1,127 Citations


Journal ArticleDOI: 10.1039/C3EE41638K
Long Qie1, Wei-Min Chen1, Henghui Xu1, Xiaoqin Xiong1  +6 moreInstitutions (2)
Abstract: Functionalized three-dimensional hierarchical porous carbon (THPC) is prepared via a facile modified chemical activation route with polypyrrole microsheets as precursor and KOH as activating agent. The as-obtained THPC presents a large specific surface area (2870 m2 g−1), high-level heteroatom doping (N: 7.7 wt%, O: 12.4 wt%), excellent electrical conductivity (5.6 S cm−1), and hierarchical porous nano-architecture containing macroporous frameworks, mesoporous walls and microporous textures. Such unique features make the THPC an ideal electrode material for electrochemical energy storage. As the electrode material for a supercapacitor, the THPC exhibits a high capacitance, excellent rate performance and long-term stability in both aqueous and organic electrolytes.

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922 Citations