An electrochemically active lithium–nickel vanadate phase of LiNiVO containing VO tetrahedrons has been synthesized by soft chemical method through a new mild liquid route at 450℃ for 3h in air. The products were characterized by X-ray diffraction, thermal analysis, SEM, IR and Raman spectra, respectively. The cells using lithium-nickel vanadate as a cathode can be cycled between 4.8 and 3.0V (vs. Li) at current density of 0.2mA/cm2. The results indicated that the low-temperature specimen prepared by liquid route exhibited better electrochemical properties than the high-temperature specimen obtained by solid-state reaction.

Spinel compound LiNi1-xMnxVO4 (0≤x≤0.4) had been prepared by using the moist chemical method. X-ray di4raction spectra showed that the lattice constant increased with x in the LiNi1-xMnxVO4, XPS spectra indicating that Li1s had a chemical shift towards lesser binding energy, and manganese in LiNi1-xMnxVO4 existing as the mixed valence of Mn2+ and Mn3+. The electrochemical charge and discharge testing at a current density of 0.1mA/cm2 between the potentialsof 4.0 and 3.0V vs Li/Li+ in 1mol/dm3 LiPF6/EC+DEC (1:1 by volume) at 25℃ showed that LiNi1-xMnxVO4 cell hasa better rechargeability, but a lower cell voltage of 4.0V vsLi/Li+ than that without the doping sample, and the capacity and the cycle efficiency of the Li/LiNi1-xMnxVO4 cellsincreas ed with x in the LiNi1-xMnxVO4.

This paper shows that Fe(OH)2 precipitates were partially oxidized byH2O2 to ultrafine Fe3O4 powders about 8-10nm in the presence of surfactants. The magnetic fluid with various concentrations were prepared by using water and oil as carrier liquids, respectively. The phase analysis, morphology, ultrafine powder sizes and magnetic properties were measured by XRD, IR, TEMand vibrating sample magnetometer (VSM), respectively. The stability of the magnetic fluids were evaluated by testing the suspension percent. The influence of the amount of surfactants and the initial concentration of magnetic fluids on stability of the magnetic fluids was examined. The magnetization versus the concentration of magnetic fluids and carriers is also discussed.

The precursors of Li4Ti5O12 were prepared from tetrabutyl titanate and lithium acetate by sol-gel process. The Li4Ti5O12 samples were synthesized by calcining the gel precursors at 400～900℃ in air for 6～20h. Its reaction mechanism was investigated by infrared speetroseopy(IR), thermogravimetry(TG) and X-ray diffraetion(XRD). The effects of sinter-temperature, calcination-time and thermal-treatment for the products were discussed. The samples were characterized by X-ray diffraetion(XRD), scanning electron mieroseopy(SEM). The results showed that the single-phase products were obtained by calcining the gel precursors at 800℃ in air for 20h, the sintertemperature was lower than that of solid-state method, the particles were narrowly distributed, well crystallized with a size range from 0.3μm to 0.5μm.

Anode material Li4Ti5O12 for lithium-ion batteries have been synthesized by a novel sol-gel method with triethanolamine(TEA) as a chelating agent and LiAcd 2H2O and Tetrabutyl titanate [Ti(OC4H9)4] as starting materials. Various initial conditions were studied in order to find the optimal conditions for the synthesis of Li4Ti5O12. The as-prepared samples have been characterized by means of XRD, IR and SEM. Its electrochemical behavior was evaluated in a liquid electrolyte in lithium-ion batteries. These analyses indicated that the prepared Li-Ti-O powders belonged to a spinel structure and had a uniform morphology with average particle size from 223 to 105nm with the increase in TEA content. At 1.55V (vs. Li), the Li4Ti5O12 electrode with the ratio of TEA to Ti ions 0.8 exhibited an initial discharge capacity of 168mA h/g and a subsequent charge capacity of 151mA h/g. The results of cyclic voltammetry for Li4Ti5O12 showed that at the potential range from 1.5 to 1.7V (vs. Li), there was a pair of reversible redox peaks correspond to the process of Li+ intercalation and deintercalation in the spinel Li-Ti-O oxides.