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Jiang Y.,Hefei University of Technology | Wang Y.,Hefei University of Technology | Wang Y.,Key Laboratory of Functional Materials and Devices of Anhui Province | Zhang Y.,Hefei University of Technology | And 6 more authors.
Journal of Solid State Electrochemistry

Solution-phase method and solid-phase method have been implemented to synthesize highly porous carbon via a template carbonization process, in which N,O-carboxymethyl chitosan (NOCC) and Zn(NO3)2·6H2O serve as the carbon/nitrogen source and template, respectively. It reveals that different synthesis pathways have significant effects on the morphologies, structures, porosities, and capacitive properties of carbon samples. All resultant carbon samples are amorphous in nature. The C-T-1:1 sample from solution-phase method exhibits a high porosity than the C-D-1:1 sample from solid-phase method. The C-T-1:1 sample displays the highest BET surface area of 1956 m2 g−1 and a largest pore volume of 1.48 cm3 g−1 and possesses a nitrogen content of 2.06 %. Meanwhile, the C-D-1:1 sample from solid-phase method shows a lower BET surface area of 1228 m2 g−1 and a smaller pore volume of 0.9 cm3 g−1, but a higher nitrogen content of 4.22 %. As a result, the C-T-1:1 sample is endowed with outstanding electrochemical properties, whose specific capacitance reaches up to 325.0 F g−1 at 1 A g−1 when conducted in 6 mol L−1 aqueous KOH electrolyte, compared with that of 173.2 F g−1 of the C-D-1:1 sample. Furthermore, the C-T-1:1 sample still remains 174.8 F g−1 at 10 A g−1 and good stability over 5000 cycles. Thus, the solution-phase method developed herein may provide a promising route for facile and large-scale production of porous carbon materials from NOCC for high-performance supercapacitors. © 2015 Springer-Verlag Berlin Heidelberg Source

Wu D.,Hefei University of Technology | Wu S.-P.,Hefei University of Technology | Yang L.,China Electronics Technology Group Corporation | Shi C.-D.,China Electronics Technology Group Corporation | And 3 more authors.
Powder Metallurgy

An orthogonal experiment scheme was employed to study the influences of forming pressure, sintering temperature and holding time and Cu content on microstructure, hardness and electrical resistivity of the Cu/Invar composites prepared by the powder metallurgy (PM) technique. The interdiffusion of the Fe, Ni and Cu atoms of the composites during sintering was also investigated. The results show that the Invar alloy is distributed continuously in the composites, when the Cu content is 30 wt-% and below; when the Cu content is 40 wt-% and above, a continuous net structure of Cu forms. Properties, especially the electrical and thermal conductivities, depend on the relative density and atom interdiffusion of the Cu/Invar composites. Taking the electrical resistivity of the composites as index, the optimum processing parameters are: forming pressure of 600 MPa, sintering temperature of 1000°C, holding time of 60 min and Cu content of 50 wt-%. © 2015 Institute of Materials, Minerals and Mining Published by Maney on behalf of the Institute. Source

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