In situ growth of NiCo2S4 nanosheets on graphene for high-performance supercapacitors

Peng, Shengjie; Li, Linlin; Li, Cheng Chao; Tan, Hua; Cai, Ren; Yu, Hong; Mhaisalkar, Subodh; Srinivasan, Madhavi; Ramakrishna, Seeram; Yan, Qingyu

doi:10.1039/c3cc46034g

Cited by 390 publications

(232 citation statements)

References 26 publications

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“…[17][18][19][20] In particular, NiCo 2 S 4 possess higher electrochemical activity and higher capacity than mono-metal sulphides based on richer redox reactions. [ 21,22 ] More signifi cantly, NiCo 2 S 4 exhibited an excellent electrical conductivity, at least two orders of magnitude higher than that of NiCo 2 O 4 . [ 23 ] The development of novel nanostructured materials will effectively improve the utilization of active materials because of their high surface area, and short electron-and ion-transport pathways.…”

mentioning

confidence: 99%

NiCo₂S₄ Nanosheets Grown on Nitrogen‐Doped Carbon Foams as an Advanced Electrode for Supercapacitors

Shen¹,

Wang²,

Xu³

et al. 2014

Advanced Energy Materials

775

381

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mers usually suffer from poor cyclic stability in long term charge-discharge processes. [ 15 ] The low electron conductivity of transition metal oxides leads to inferior rate capability. [ 16 ] In the search for high performance electrode materials, transition-metal sulfi des have been extensively studied as new class of pseudocapacitive materials for supercapacitors. [17][18][19][20] In particular, NiCo 2 S 4 possess higher electrochemical activity and higher capacity than mono-metal sulphides based on richer redox reactions. [ 21,22 ] More signifi cantly, NiCo 2 S 4 exhibited an excellent electrical conductivity, at least two orders of magnitude higher than that of NiCo 2 O 4 . [ 23 ] The development of novel nanostructured materials will effectively improve the utilization of active materials because of their high surface area, and short electron-and ion-transport pathways. Several different types of NiCo 2 S 4 nanostructures, including nanoplates, [ 24 ] nanoprisms, [ 25 ] nanotubes, [ 26,27 ] microspheres, [ 28 ] have been recently synthesized and their electrochemical performance was investigated. For example, Lou et al. [ 25 ] reported the fabrication of Ni x Co 3-x S 4 hollow nanoprisms through a simple sacrifi cial template method and a high reversible capacity (895 F g −1 under 1 A g −1 ) can be achieved. However, it should be noted that the introduction of a conductive agent and a polymer binder during the thin fi lm electrode preparation not only increase extra contact resistance but also inevitably compromises the overall energy storage capacity that still seriously limit their performance. [ 29,30 ] Three dimensional (3D) electrode architectures have emerged as a new direction because it can provide 3D interconnected network of both electron and ion pathways, allowing for effi cient charge and mass exchange during faradic redox reactions. Greatly enhanced performance has kindled the interest of researchers in the fi eld of 3D electrode architectures designs, such as copper pillar array, [ 31 ] nickel network, [ 32,33 ] stainless steel mesh, [ 34 ] carbonaceous interpenetrating structures. [ 35 ] The rigid electrode with metals as current collectors lead to the devices less fl exible, and they also have a low energy density. Carbon nanotubes sponge and graphene foams have been recently fabricated using chemical vapor deposition and used as electrode architectures for supercapacitors. [36][37][38] However, it is diffi cult to produce carbonaceous foams in large-scale because of their relatively high-cost and complex preparation processes. Additionally, due to the potential incompatibility issue between To push the energy density limit of supercapacitors, a new class of electrode materials with favorable architectures is strongly needed. Binary metal sulfi des hold great promise as an electrode material for high-performance energy storage devices because they offer higher electrochemical activity and higher capacity than mono-metal sulfi des. Here, the rational design and fabrication of NiCo 2 S 4 nan...

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mentioning

confidence: 99%

NiCo₂S₄ Nanosheets Grown on Nitrogen‐Doped Carbon Foams as an Advanced Electrode for Supercapacitors

Shen¹,

Wang²,

Xu³

et al. 2014

Advanced Energy Materials

775

381

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“…On the other hand, increasing conductivity will greatly favor the Faradaic reactions, which has been demonstrated typically in the integration of oxides with metal foam, 13 carbon cloth, 9 graphene and carbon nanotubes. 14 However, these methods do not change the intrinsic properties of the metal oxides. 15,16 Therefore, achieving the co-existence of large specific surface area and high conductivity in metal oxides themselves has been desired.…”

Section: Introductionmentioning

confidence: 99%

Integrating large specific surface area and high conductivity in hydrogenated NiCo2O4 double-shell hollow spheres to improve supercapacitors

et al. 2015

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Increasing specific surface area and electrical conductivity are two crucial ways to improve the capacitive performance of electrode materials. Nanostructure usually enlarges the former but reduces the later; thus, it is still a great challenge to overcome such contradiction. Here, we report hydrogenated NiCo 2 O 4 double-shell hollow spheres, combining large specific surface area and high conductivity to improve the capacitive performance of supercapacitors. The specific surface area of NiCo 2 O 4 hollow spheres, fabricated via programmed coating of carbon spheres, was enlarged 50% (from 76.6 to 115.2 m 2 g − 1 ) when their structure was transformed from single-shell to double-shell. Furthermore, activated carbon impedance measurements demonstrated that the low-temperature hydrogenation greatly decreased both the internal resistance and the Warburg impedance. Consequently, a specific capacitance increase of 462%, from 445 to 718 F g − 1 , was achieved at a current density of 1 A g − 1 .Underlying such great improvement, the evolution of chemical valence and defect states with co-increase of these two factors was explored through X-ray photoelectron spectroscopy. Moreover, a full cell combined with NiCo 2 O 4 and AC was assembled, and an energy density of 34.8 Wh kg − 1 was obtained at a power density of 464 W kg − 1 . NPG Asia Materials (2015) 7, e165; doi:10.1038/am.2015.11; published online 13 March 2015 INTRODUCTION Supercapacitors, also known as electrochemical capacitors, have attracted great attention because of their outstanding power density, long cycling life and fast charge/discharge ability. 1-3 These virtues make them remarkable candidates for the electrical sources of hybrid electric vehicles, for which strong explosiveness is highly desired. Principally, supercapacitors run according to ion adsorption (electrochemical double-layer capacitors) or fast Faradaic reactions (pseudocapacitors) mechanisms. Comparatively speaking, the former has low specific capacitance and hence hard to satisfy the growing demand of peak-power assistance in electric vehicles. 4 Thus, more and more attentions were focused on pseudocapacitive electrode materials because their energy density associated with Faradaic reactions is much larger than that of electrochemical double-layer capacitors. [5][6][7][8] To improve performances of pseudocapacitors, two crucial factors are usually considered for the electrode materials, they are large specific surface area and high conductivity for electrolyte ions and electrons. On the one hand, large specific surface area will provide more electroactive sites for the Faradaic reactions, and load more doublelayer charges. Along such idea, many kinds of nanomaterials, 9-11 especially hollow spheres, 12 have been developed to improve

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“…Our performance is superior to that of all reported ternary nickel cobalt sulfides based materials (literature reports were summarized in Supplementary Table S1). 24,34,38,40,[46][47][48][49][50] This phenomenon may be attributed to the unique double shell structure which offers many desirable features. First of all, the highly porous double shells surfaces are covered with self-assembled nanosheets which are full of mesopores (with size distribution centered around 3-5 nm, Supplemental Figure S7B).…”

Section: Resultsmentioning

confidence: 99%

Self-templating Scheme for the Synthesis of Nanostructured Transition-Metal Chalcogenide Electrodes for Capacitive Energy Storage

2015

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Due to their unique structural features including well-defined interior voids, low density, low coefficients of thermal expansion, large surface area and surface permeability, hollow micro/nanostructured transition metal sulfides with high conductivity have been investigated as new class of electrode materials for pseudocapacitor applications. Herein, we report a novel self-templating strategy to fabricate well-defined single and double-shell NiCo 2 S 4 hollow spheres, as a promising electrode material for pseudocapacitors. The surfaces of the NiCo 2 S 4 hollow spheres consist of self-assembled 2D mesoporous nanosheets. This unique morphology results in a high specific capacitance (1263 F g -1 at 2 A g -1 ), remarkable rate performance (75.3% retention of initial capacitance from 2 A g -1 to 60 A g -1 ) and exceptional reversibility with a cycling efficiency of 93.8% and 87% after 10,000 and 20,000 cycles, respectively, at a high current density of 10 A g -1 . The cycling stability of our ternary chalcogenides is comparable to carbonaceous electrode materials, but with much higher specific capacitance (higher than any previously reported ternary chalcogenide), suggesting that these unique chalcogenide structures have potential application in next-generation commercial pseudocapacitors.

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In situ growth of NiCo2S4 nanosheets on graphene for high-performance supercapacitors

Abstract: We demonstrate a facile hydrothermal method for growth of ultrathin NiCo2S4 nanosheets on reduced graphene oxide (RGO), which exhibit remarkable electrochemical performance with higher capacitance and longer cycle life than the bare NiCo2S4 hollow spheres (HSs).

Cited by 390 publications

References 26 publications

NiCo₂S₄ Nanosheets Grown on Nitrogen‐Doped Carbon Foams as an Advanced Electrode for Supercapacitors

NiCo₂S₄ Nanosheets Grown on Nitrogen‐Doped Carbon Foams as an Advanced Electrode for Supercapacitors

Integrating large specific surface area and high conductivity in hydrogenated NiCo2O4 double-shell hollow spheres to improve supercapacitors

Self-templating Scheme for the Synthesis of Nanostructured Transition-Metal Chalcogenide Electrodes for Capacitive Energy Storage

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In situ growth of NiCo2S4 nanosheets on graphene for high-performance supercapacitors

Abstract: We demonstrate a facile hydrothermal method for growth of ultrathin NiCo2S4 nanosheets on reduced graphene oxide (RGO), which exhibit remarkable electrochemical performance with higher capacitance and longer cycle life than the bare NiCo2S4 hollow spheres (HSs).

Cited by 390 publications

References 26 publications

NiCo2S4 Nanosheets Grown on Nitrogen‐Doped Carbon Foams as an Advanced Electrode for Supercapacitors

NiCo2S4 Nanosheets Grown on Nitrogen‐Doped Carbon Foams as an Advanced Electrode for Supercapacitors

Integrating large specific surface area and high conductivity in hydrogenated NiCo2O4 double-shell hollow spheres to improve supercapacitors

Self-templating Scheme for the Synthesis of Nanostructured Transition-Metal Chalcogenide Electrodes for Capacitive Energy Storage

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NiCo₂S₄ Nanosheets Grown on Nitrogen‐Doped Carbon Foams as an Advanced Electrode for Supercapacitors

NiCo₂S₄ Nanosheets Grown on Nitrogen‐Doped Carbon Foams as an Advanced Electrode for Supercapacitors