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Ai Y.,University of Electronic Science and Technology of China | Ai Y.,Chinese Academy of ScienceBeijing | Geng X.,Chinese Academy of ScienceBeijing | Lou Z.,Chinese Academy of ScienceBeijing | And 2 more authors.
ACS Applied Materials and Interfaces | Year: 2015

Effectively composite materials with optimized structures exhibited promising potential in continuing improving the electrochemical performances of supercapacitors in the past few years. Here, we proposed a rational design of branched CoMoO4@CoNiO2 core/shell nanowire arrays on Ni foam by two steps of hydrothermal processing. Owing to the high activity of the scaffold-like CoMoO4 nanowires and the well-defined CoNiO2 nanoneedles, the three-dimensional (3D) electrode architectures achieved remarkable electrochemical performances with high areal specific capacitance (5.31 F/cm2 at 5 mA/cm2) and superior cycling stability(159% of the original specific capacitance, i.e., 95.7% of the maximum retained after 5000 cycles at 30 mA/cm2). The all-solid-state asymmetric supercapacitors composed of such electrode and activated carbon (AC) exhibited an areal specific capacitance of 1.54 F/cm2 at 10 mA/cm2 and a rate capability (59.75 Wh/kg at a 1464 W/kg) comparable with Li-ion batteries. It also showed an excellent cycling stability with no capacitance attenuation after 50000 cycles at 100 mA/cm2. After rapid charging (1 s), such supercapacitors in series could lighten a red LED for a long time and drive a mini motor effectively, demonstrating advances in energy storage, scalable integrated applications, and promising commercial potential. © 2015 American Chemical Society.

Luo M.,Georgia Institute of Technology | Luo M.,Wuhan University | Huang H.,Georgia Institute of Technology | Choi S.-I.,Georgia Institute of Technology | And 7 more authors.
ACS Nano | Year: 2015

This article describes a seed-mediated approach to the synthesis of Ag nanorods with thin diameters and tunable aspect ratios. The success of this method is built upon our recent progress in the synthesis of Pd decahedra as uniform samples, together with controllable sizes. When used as a seed, the Pd decahedron could direct the deposition of Ag atoms along the 5-fold axis to generate a nanorod, with its diameter being determined by the lateral dimension of the seed. We were able to generate Ag nanorods with uniform diameters down to 20 nm. Under the conditions we used for growth, symmetry breaking occurred as the Ag atoms were only deposited along one side of the Pd decahedral seed to generate a Ag nanorod with the Pd seed being positioned at one of its two ends. We also systematically investigated the localized surface plasmon resonance (LSPR) properties of the Ag nanorods. With the transverse mode kept below 400 nm, the longitudinal mode could be readily tuned from the visible to the near-infrared region by varying the aspect ratio. As an important demonstration, we obtained Ag nanorods with no LSPR peak in the visible spectrum (400-800 nm), which are attractive for applications related to the fabrication of touchscreen displays, solar films, and energy-saving smart windows. © 2015 American Chemical Society.

Wang B.B.,Chongqing University of Technology | Zhu K.,Chinese Academy of ScienceBeijing | Feng J.,Xiamen University | Wu J.Y.,Xiamen University | And 3 more authors.
Journal of Alloys and Compounds | Year: 2016

Molybdenum oxide nanorods were synthesized on different substrates in the thermal chemical vapour deposition system at low pressure, where the molybdenum trioxide and selenium powders were used as the source materials. The results of field emission scanning electron microscope, transmission electron microscope, X-ray diffractometer, energy dispersive X-ray spectrometer and micro-Raman spectroscope indicate that the molybdenum oxide nanorods have a single-crystalline structure and are mainly composed of MoO3 with traces of MoO2 and Mo4O11. A vapour-solid growth mechanism based on the condensation of MoO3-x molecules and the diffusion of MoO3 molecules on the substrate has been proposed to explain the formation of molybdenum oxide nanorods. Furthermore, the photoluminescence (PL) properties of molybdenum oxide nanorods have been studied in Ramalog system using a 325 nm line of He-Cd laser as the excitation source. The PL results show that the molybdenum oxide nanorods generate strong green PL bands located at about 510 and 521 nm and weak PL band located at about 654 nm, which are related to the defects in the molybdenum oxide nanorods. The outcomes can enrich our knowledge on the synthesis and optical properties of molybdenum oxide nanomaterials and contribute to the development of optoelectronic devices related to molybdenum oxide nanomaterials. © 2015 Elsevier B.V.

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