V 2 O 3 powder is frequently used in conductive polymer composites and in catalysts. [1][2][3] In addition, a variety of VO x and MVO x (e.g., V 2 O 5 , V 6 O 13 , CaV 3 O 7 ) compounds have been suggested and tested as cathode materials for rechargeable Li batteries. [4][5][6][7][8][9][10] These vanadium oxide-based compounds are still among the most intensively studied cathode materials for rechargeable Li batteries. It should be noted that studies related to Li-battery materials are of high interest in materials science. [11][12][13][14] The synthesis of spherical V 2 O 3 nanoparticles by the reductive pyrolysis of ammonium oxovanadium(IV) carbonato hydroxide has been reported. [15] Nanocrystalline V 2 O 3 was synthesized by the thermal decomposition of divanadium pentoxide by Su and Schlogl. [16] In this report, we present results of the RAPET dissociation (RAPET: reaction under autogenic pressure at elevated temperatures) of VO(OC 2 H 5 ) 3 , which produces carbon-coated vanadium oxide (CCVO). This novel method, using only a metallic alkoxide precursor in the absence of a catalyst or a solvent, is a one-step process yielding a core/shell morphology. Further oxidation of the CCVO produces carbon-coated V 2 O 5 (CCV 2 O 5 ) nanoparticles. In the present study, we explore to what extent the carbon shell enables electrical contact among the CCVO particles, while not interfering with a smooth Li intercalation with the V 2 O 3 particles. It is interesting to discover whether these active materials can be used in composite electrodes for Li batteries, as they would possibly reduce the need for significant addition of carbonaceous materials, in order to maintain electrical contact among the particles and between the active mass and the current collector. Usually, composite cathodes based on Li-intercalating transition-metal oxides or sulfides have to include additional carbon particles (5-15 wt %) [17,18] in order to achieve electrical contact between the active mass and the current collector (and among the particles themselves). As the particles are smaller (which may be very important for achieving high rates), critical problems may arise regarding the electrical properties of the composite electrodes, because the carbon particles may not be in direct contact with all of the very small particles of the active mass. Hence, the use of an active mass where each particle is coated by a thin (conductive) carbon layer that is permeable to Li ions may be very advantageous for Li-battery application. This paper is the first report on the use of CCVO as the active mass in composite cathodes for rechargeable Li batteries. The carbon and hydrogen content in the CCVO samples was determined by elemental analysis measurements. The calculated elemental percentage of carbon in the precursor, VO(OC 2 H 5 ) 3 , was 44.3 %, while the elemental percentage of hydrogen was 9.6 %. The measured percentage of carbon in the carbon-coated V 2 O 3 (CCV 2 O 3 ) product is usually 30 %, while the percentage of hydrogen is only 0.3 %. Hence, it...

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Electrodes F 3000 Testing Carbon-Coated VO x Prepared via Reaction under Autogenic Pressure at Elevated Temperature as Li-Insertion Materials. -Nanoparticles of pure V2O3 (30-100 nm) coated with uniform 15 nm thick carbon layers are prepared by heating VO(O-Et)3 in closed vessels at 700°C under autogenic pressure. Further heating of this material in air at 400°C leads to V2O5 nanoparticles with a 4 nm thick carbon coating. Both materials can insert/deinsert Li ions reversibly in nonaqueous Li salt solutions at a capacity close to 270 mAh/g, corresponding to the insertion of 2 Li per V2O5. The performance of these electrodes in terms of reversible capacity and rates is much better than that of electrodes containing nanoparticles of V2O5 with no carbon coating. -(ODANI, A.; POL, V. G.; POL, S. V.; KOLTYPIN, M.; GEDANKEN*, A.; AURBACH, D.; Adv.

A small-angle X-ray scattering method has been developed for the quantitative evaluation of the effectiveness of nanoparticle dispersion in polymer matrices; it is termed the nanoscale dispersion index. This method was applied to dispersions of nanosized TiO 2 fillers in polypropylene. Master batches prepared with lower filler contents showed better dispersion as evaluated by the nanoscale dispersion index. The addition of 1,3:2,4-di(3,4-dimethylbenzylidene) sorbitol to the compounds did not affect the degree of nanoscale dispersion as estimated by the nanoscale dispersion index.