Browsing by Author "Wang, XC"

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    High rate capability core–shell lithium titanate@ceria nanosphere anode material synthesized by one-pot co-precipitation for lithium-ion batteries
    (Elsevier, 2014-07-01) Yang, XJ; Huang, YD; Wang, XC; Jia, DZ; Pang, WK; Guo, ZP; Tang, XC
    Core–shell Li4Ti5O12@CeO2 nanosphere has been synthesized by a one-pot co-precipitation method. The structure and morphology of the as-prepared materials have been analyzed by X-ray diffraction and transmission electron microscopy. The results show that CeO2 is successfully coated on the surface of the Li4Ti5O12 besides partial doping of Ce4+ into the Li4Ti5O12 structure. The Li4Ti5O12@CeO2 nanosphere exhibits excellent capacity of 152 mAh g−1 even after 180 cycles at 10 C, with no noticeable capacity fading. Furthermore, the sample shows much improved rate capability at 40 C compared with pure Li4Ti5O12 when used as anode material for lithium-ion batteries. The introduction of CeO2 enhances not only the electric conductivity of Li4Ti5O12, but also the lithium ion diffusivity in Li4Ti5O12, resulting in significantly improved electrochemical performance of the Li4Ti5O12. © 2014, Elsevier B.V.
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    Synthesis and thermoelectric properties of single crystalline and polycrystalline Ba8Ga16Ge30
    (Elsevier, 2010-02-18) Wang, HF; Cai, KF; Li, H; Yu, DH; Wang, XC; Zhou, CW; Li, XL; Wang, YY; An, BJ; Du, Y
    Large Ba8Ga16Ge30 single crystals were synthesized by a Ga-flux method. The single crystals were characterized by X-ray diffraction and energy-dispersive X-ray spectroscopy. The cubic structure of Ba filled type-I germanium clathrates with lattice parameter of 10.767 Å has been confirmed. The Ba8Ga16Ge30 polycrystalline sample was prepared by melting the synthesized single crystals. Thermoelectric properties of the single crystalline and polycrystalline Ba8Ga16Ge30 samples were measured from room temperature to 773 K. The single crystalline sample shows p-type conduction, while the polycrystalline sample exhibits n-type conduction and typical heavily doped semiconducting behavior. At room temperature, the electrical conductivity of the polycrystalline sample is much higher than that of the single crystalline sample, whereas the absolute value of Seebeck coefficient of the single crystalline sample is higher than that of the polycrystalline sample. The maximum power factor for the single crystalline and polycrystalline samples reaches ~17 μW cm−1 K−2 at 773 K and ~10 μW cm−1 K−2 at 500 K, respectively. © 2010, Elsevier Ltd.