Preparation and Capacitive Behavior of Dandelion-Likeγ-MnO2Nanofibre/Activated Carbon Microbeads Composite for the Application of Supercapacitor

Dandelion-likeγ-manganese dioxide (γ-MnO2) nanofibre/activated carbon microbeads (ACMBs) composite is prepared by an in situ coating technique. The structure and morphology of the composite are characterized by scanning electron microscopy and X-ray diffraction. The results show thatγ-MnO2nanofibre is uniformly encapsulated on the surface of ACMB, and the composite finally becomes a dandelion-like microbead. Cyclic voltammetry, galvanostatic current charge/discharge, and cycle life measurements are used to evaluate the electrochemical behaviors of the composite. Since the composite is able to undergo pseudofaradic charge transfer reactions and hereto contributes together with the double-layer effect to the total capacitance of the material, the specific capacitance of the composite is as high as 375.9 F g-1at a scan rate of 1 mV s-1, which is significantly higher than the pure ACMB. Besides, the capacitance retention of the supercapacitor using the composite as electrode-active material keeps still 93% after 1000 cycles.

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Rechargeable nonaqueous lithium/Mo6S8 battery

Canadian Journal of Physics ◽

10.1139/p84-071 ◽

1984 ◽

Vol 62 (6) ◽

pp. 527-531 ◽

Cited By ~ 27

Author(s):

P. J. Mulhern ◽

R. R. Haering

Keyword(s):

Discharge Rate ◽

Active Material ◽

Rate Capability ◽

Constant Current ◽

Electrochemical Cells ◽

X Ray Diffraction ◽

X Ray ◽

Long Cycle Life

Electrochemical cells based on the intercalation of lithium into Mo6S8 were examined by derivative constant current chronopotentiometry, in situ X-ray diffraction, and long-term cycling. About three-quarters of the capacity of such cells oeeurs between 2.0 and 2.1 V with most of the remainder near 2.45 V. Li/Mo6S8 cells have a long cycle life, good discharge rate capability, and an energy density of at least 260 W∙h/kg (1 W∙h = 3.6 kJ) of active material. Such cells can be made by starting with cathodes made from ternary Chevrel phase compounds. AyMo6S8 (A = Cu, Fe, Ni), and electrochemically converting these materials to form LixMo6S8.

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Real-Time Investigations on the Formation of Cu(In,Ga)Se2 While Annealing Precursors Produced with a Combination of Sputtering and Thermal Evaporation

MRS Proceedings ◽

10.1557/proc-1012-y10-01 ◽

2007 ◽

Vol 1012 ◽

Author(s):

Stefan Jost ◽

Frank Hergert ◽

Rainer Hock ◽

Michael Purwins

Keyword(s):

Thin Films ◽

Real Time ◽

Thermal Evaporation ◽

Indium Selenide ◽

Transfer Reactions ◽

X Ray Diffraction ◽

X Ray ◽

Precursor Phase ◽

Elemental Layer

AbstractWe have investigated the formation of Cu(In,Ga)Se2 thin films by real-time X-ray diffraction (XRD) experiments while annealing differently deposited and composed stacked elemental layer (SEL) precursors.The in-situ measurements during the selenization of bi-layered Cu/In precursors reveal, that the semiconductor formation process is similar for precursors with thermally evaporated or sputtered indium. In both cases, the formation of binary copper and indium selenides is observed at temperatures around the melting point of selenium. After subsequent selenium transfer reactions, the chalcopyrite CuInSe2 is formed from the educt phases Cu2-xSe and InSe.The addition of gallium leads to the formation of the intermetallic precursor phase Cu9Ga4, which reduces the overall amount of copper and gallium selenides at process temperatures above 500 K. This causes an ongoing selenization in the indium selenium subsystem, which results in the formation of CuInSe2 from the educt phases Cu2-xSe and the selenium richest indium selenide g-In2Se3.

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Structural change of activated carbon fibers with desorption by in situ X-ray diffraction

Carbon ◽

10.1016/0008-6223(88)90078-4 ◽

1988 ◽

Vol 26 (5) ◽

pp. 743-745 ◽

Cited By ~ 54

Author(s):

T. Suzuki ◽

K. Kaneko

Keyword(s):

Activated Carbon ◽

Structural Change ◽

Carbon Fibers ◽

Activated Carbon Fibers ◽

X Ray Diffraction ◽

X Ray

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The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071107 ◽

1973 ◽

Vol 31 ◽

pp. 132-133 ◽

Cited By ~ 1

Author(s):

R. E. Herfert

Keyword(s):

Surface Characterization ◽

Analytical Techniques ◽

X Ray Diffraction ◽

Depth Of Penetration ◽

X Ray ◽

The Past ◽

Transmission Electron ◽

Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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