Amorphous nickel hydroxide nanospheres with ultrahigh capacitance and energy density as electrochemical pseudocapacitor materials

Li, H. B.; Yu, Minghao; Wang, F. X.; Liu, P.; Liang, Yu-Jing; Xiao, Jianfeng; Wang, C. X.; Tong, Yexiang; Yang, Guangwu

doi:10.1038/ncomms2932

Cited by 1,099 publications

(450 citation statements)

References 31 publications

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“…On the other hand, recent research implies that amorphous structure is commensurate with crystalline materials in supercapacitors owing to the similar reason. 22 Figures 5c and d are the high resolution X-ray photoelectron spectroscopy spectra of Ni 2p and Co 2p for NiCo 2 O 4 annealed at 300°C, respectively. It shows that the surface of the sample has a composition containing Ni 2+ , Ni 3+ , Co 2+ and Co 3+ with two and one shakeup satellites, respectively.…”

Section: Electrochemical Measurementsmentioning

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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Section: Electrochemical Measurementsmentioning

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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“…The reaction process was facile and efficient, simply involving heating the reactants under reflux in ethylene glycol for 1 h. Yang and colleagues [76][77][78] have also contributed to the synthesis of amorphous hydroxide materials by preparing flower-like spherical nanostructures using a unique electrochemical technique that is simple, green and inexpensive. These spheres and hollow structures are interesting candidates for use in energy storage [94].…”

Section: Science China Materialsmentioning

confidence: 99%

“…The large number of under-coordinated atoms (good electron acceptors) and reactive sites at the surface means that amorphous materials also have the advantage over crystalline ones in their contact with the electrolyte and active substances (electron donors), which favors electrochemical processes. In regard to the merits discussed above, amorphous nanomaterials have already demonstrated their superior performance over bulk crystalline materials in various electrochemical applications, including lithium-and/or sodium-ion batteries [51,62,66,71,79,84,[96][97][98][99][100], super-or pseudo-capacitors [77,78,83], electrochemical water splitting [59] and sensors [72,81]. The amorphous CoSnO 3 @C nanoboxes reported by Wang et al [79] showed high initial discharge and charge capacities of around 1,410 and 480 mA h g −1 , respectively, as revealed in Fig.…”

Section: Applications Electrochemical Electrode Materialsmentioning

confidence: 99%

“…Research on Ni(OH) 2 has thus far focused on the crystalline rather than the amorphous phase, despite the impressive electrochemical properties of the latter, which shows improved electrochemical efficiency over its crystalline counterpart because of increased disorder. Li et al [77] found that electrochemically deposited amorphous Ni(OH) 2 nanospheres exhibited high capacitance (2,188 F g −1 at a scan rate of 1 mV s −1 ). Asymmetric pseudocapacitors of amorphous Ni(OH) 2 also showed high capacitance (153 F g −1 ), high energy density (35.7 W h kg −1 at a power density of 490 W kg −1 ), and extremely long cycle life (charge retention of 97% and 81% after 5,000 and 10,000 cycles, respectively).…”

Section: Applications Electrochemical Electrode Materialsmentioning

confidence: 99%

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Tailoring the shape of amorphous nanomaterials: recent developments and applications

2015

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Nanoscale amorphous materials are very important member of the non-crystalline solids family and have emerged as a new category of advanced materials. However, morphological control of amorphous nanomaterials is very difficult because of the atomic isotropy of their internal structures. In this review, we introduce some emerging innovative methods to fabricate well-defined, regular-shaped amorphous nanomaterials. We then highlight some examples to evaluate the use of these amorphous materials in electrodes, and their optical response. There is still plenty of room to explore the amorphous world. As researchers continue to advance the scientific tools that underpin the concepts related to "amorphous", additional applications of these materials will emerge. Their controlled synthesis will undoubtedly attain new heights in the discipline of nanomaterials, and allow nanoscale amorphous materials to become more sophisticated, diverse, and mainstream.

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“…In this study, amorphous electrode material was preferred over the crystalline material owing to the fact that amorphous materials demonstrated moderate structural disorder facilitating faster ion diffusion by forming irregular surfaces providing high specific surface area and suitable pore size distribution 187, 188. The fabricated all‐solid state device exhibited a large specific capacitance of 350.2 F g −1 at 0.5 A g −1 current density while maintaining a good rate capability of 159.5 F g −1 even at high current density of 20 A g −1 .…”

Section: Fiber‐shaped Energy Storage Devicesmentioning

confidence: 99%

Fiber‐Type Solar Cells, Nanogenerators, Batteries, and Supercapacitors for Wearable Applications

et al. 2018

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Wearable electronic devices represent a paradigm change in consumer electronics, on‐body sensing, artificial skins, and wearable communication and entertainment. Because all these electronic devices require energy to operate, wearable energy systems are an integral part of wearable devices. Essentially, the electrodes and other components present in these energy devices should be mechanically strong, flexible, lightweight, and comfortable to the user. Presented here is a critical review of those materials and devices developed for energy conversion and storage applications with an objective to be used in wearable devices. The focus is mainly on the advances made in the field of solar cells, triboelectric generators, Li‐ion batteries, and supercapacitors for wearable device development. As these devices need to be attached/integrated with the fabric, the discussion is limited to devices made in the form of ribbons, filaments, and fibers. Some of the important challenges and future directions to be pursued are also highlighted.

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Amorphous nickel hydroxide nanospheres with ultrahigh capacitance and energy density as electrochemical pseudocapacitor materials

Cited by 1,099 publications

References 31 publications

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

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

Tailoring the shape of amorphous nanomaterials: recent developments and applications

Fiber‐Type Solar Cells, Nanogenerators, Batteries, and Supercapacitors for Wearable Applications

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