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The structure and the room temperature performances of sulfur cathodes composed of sulfur, carbon, and poly(ethylene oxide) (PEO) binder were studied with varying preparation method and binder content. Two different methods, ball mixing and mechanical stirring, were employed for preparation of slurry to obtain morphologically different cathodes. The cathodes prepared with mechanical stirring (SC cathodes) revealed more porous structure than those with ball mixing (BC cathodes). Scanning electron microscopy observations showed that sulfur particles were covered with dense and thick PEO film in the BC cathodes, whereas sulfur particles were bonded with porous PEO film in the SC cathodes. The SC-based cells exhibited much higher discharge capacity yielding 75% of sulfur utilization than the BC-based cells. The difference of discharge behaviors with different mixing methods indicates that the porosity of the cathode and the morphology of PEO binder are highly important factors for favorable electrochemical performance of lithium sulfur batteries. The cycle life of the SC-based cell was improved with the increase of binder content and with the roll pressing due to the increase of adhesiveness and cohesiveness of the sulfur cathode. © 2002 The Electrochemical Society. All rights reserved.

Al-doped ZnO (AZO) films were deposited onto glass substrates by RF magnetron sputtering for solar cell applications. The effects of the Al 2 O 3 doping concentration on the structural, electrical, and optical properties of the AZO films were investigated. As the Al 2 O 3 doping concentration was increased to 4.0 wt %, X-ray diffraction (XRD) showed a deterioration in the (002) peak intensity and a shift towards a higher angle. The best electrical properties ( ¼ 9:8 Â 10 À4 cm, H ¼ 22 cm 2 V À1 s À1 , and n e ¼ 2:89 Â 10 20 cm À3 ) were obtained in the AZO sample containing 2 wt % Al 2 O 3 . Optical transmission >83% in the visible range was also observed and the optical bandgap was increased to 3.63 eV at an Al 2 O 3 concentration of 4 wt %. For photoluminescence (PL) spectra, one UV emission peak at approximately 3.2 eV and a broad peak in the visible range from 2.3 to 2.7 eV were observed at Al 2 O 3 doping concentrations ranging from 0 -2.0 wt %. Blue emission at 2.67 eV, which indicates a non-stoichiometric structure, was only observed in the 4 wt % doped AZO films.

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