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Yu D.J.,Zhejiang Sci-Tech University | Yuan Y.F.,Zhejiang Sci-Tech University | Yuan Y.F.,Zhejiang University | Zhang D.,Hang Zhou City of Quality and Technical Supervision and Testing Institute | And 6 more authors.
Electrochimica Acta

A facile twice-hydrothermal method is developed for large-scale growth of NiCo2S4 nanotube array on Ni foam with robust adhesion. As-prepared materials are characterized by SEM, XRD and EDS. It can be observed that NiCo2S4 nanotubes directly grow on Ni foam with an average inner-diameter of ∼ 55 nm, external-diameter of 100 nm, and length of ∼ 2 μm. When evaluated as a binder-free anode for LIBs, NiCo2S4 nanotube array exhibits outstanding lithium-storage performance that includes high special capacity, excellent cyclic stability and desirable rate capability. At 0.2 C rate, NiCo2S4 nanotube array delivers the average discharge capacity of 720 mAh g-1 during 50 cycles that slightly surpasses its theoretical capacity of 703 mAh g-1. When the current comes back to 0.2 C after rate measurements, NiCo2S4 nanotubes can still stably deliver the discharging capacity of 652 mAh g-1, reaching 92.7% of that at the initial 0.2 C. Cyclic Voltammetry (CV) measurements reveal that NiCo2S4 nanotube array contains two sets of electrochemical reaction behavior come from Ni and Co. The unique NiCo2S4 nanotube array exhibits great potential as an anode material for high-performance Lithium-ion batteries. © 2016 Elsevier Ltd. All rights reserved. Source

Yuan Y.F.,Zhejiang Sci-Tech University | Yuan Y.F.,Zhejiang University | Lin J.X.,Zhejiang Sci-Tech University | Zhang Z.Q.,Zhejiang Sci-Tech University | And 6 more authors.
Materials Letters

CoMoO4 nanoflake-assembling porous pillar array is synthesized on Ni foam by a facile hydrothermal method. XRD, SEM and TEM demonstrate that CoMoO4 nanoflakes like flower petals cross and stack to form the porous pillar. As electrode materials of supercapacitors, CoMoO4 nanoflake-assembling porous pillar array show two pair of redox CV peaks, and the charging-discharging curves are also non-linear. This suggests its pseudocapacitance nature. A maximum areal specific capacitance of 1.92 F cm-2 is obtained at 4 mA cm-2. The galvanostatic cycling test and rate test reveal good cycling stability and rate capability. © 2015 Elsevier B.V. All rights reserved. Source

Zhang D.,Hang Zhou City of Quality and Technical Supervision and Testing Institute | Xiang J.,Narada Power Source Co. | Zhu Y.,Hang Zhou City of Quality and Technical Supervision and Testing Institute | Li G.,Architectural Design and Research Institute of Zhejiang Province | And 6 more authors.
Journal of Nanoscience and Nanotechnology

Porous and solid FeS2 particles are both synthesized via solid-state reaction method using FeC2O4 · 2H 2O and S powder as the raw materials. The difference of the mophology is adjusted by the calcination time. The porous FeS2 electrode exhibits significantly improved and less improved electrochemical performance comparing to the solid one during the initial 15 cycles and the later cycling process, respectively. The significantly improvement in the initial 15 cycles is due to the large surface area and 3D conducting network of the porous structure, which provides large active electrochemical interface of the active particles and electrolyte, and shortens the path length for Li+ transport. The less improvement during the later cycling process is attributed to the unstable porous structure, which collapses into nanoparticles after long cycles. On the basis of the analysis, a theoretical proposal to optimize the structure of FeS2 electrode is provided.© 2014 American Scientific Publishers. Source

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