LiFePOa/carbon composite cathode material was prepared by granulating and subsequent pyrolysis processing in N2 atmosphere with polyvinyl alcohol （PVA） as the carbon source. The influences of carbon content on the microstructure and battery performance were investigated. Single LiFePO4 phase and amorphous carbon can be found in the products. A special micro-morphology of the optimum sample was observed. The discharge capacity of the cell with the optimum cathode was 135 mAh.g^-1, close to the charge capacity of 153 mAh.g^-1 at 17 mA.g^-1. The influence of ambient temperature on the cell capacity was investigated. The temperature dependence of its electrochemical characteristic was evaluated by using AC impedance spectroscopy. A new equivalent circuit based on the charge and mass transfer control process in an electrode was proposed to fit the obtained AC impedance spectra. The tendency of every element in the equivalent circuit was used to interpret the temperature dependence of the capacity of the optimum cathode.
The present paper focused on the preparation of hydrogen titanate nanotubes and nanowires and their conversion into titania by heat treatments.The structural,morphology and optical properties of as-prepared nanostructured titanate and titania were investigated by transmission electron microscopy (TEM),X-ray diffraction (XRD) and diffusive reflectance spectra.The slim diameter of these nanostructured titanate and titania,the versatile crystal structure and special optical and electronic properties may make them find versatile applications in chemical sensors for multiple purposes.
