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Abstract: This work introduces a novel solution system not slurry to synthesize nano-micron sized Li4Ti5O12 by spray drying followed by solid-state calcination at several temperatures between 650 and 800°C. Well-crystallized Li4Ti5O12 with no impurity can be obtained at temperatures of 650, 700, 750 and 800 °C owing to the effect of nanoscale and uniform precursor powders. However, the spherical shape of the precursor powders is maintained after post-treatment at temperatures of 650 and 700°C. Because of the rough and porous nano-micron sized spherical particles, the Li4Ti5O12 obtained at relatively low calcined temperatures of 650 and 700°C show better rate capabilities than them of the Li4Ti5O12 obtained at higher temperatures of 750 and 800°C. At the relatively low calcined temperature of 650°C, the Li4Ti5O12 shows the best electrochemical performance. The initial discharge capacities are 174.8, 170.5, 167.5, 165.3, 158.2, 152.1, 130.9 and 111.9mAhg−1 at the 0.1C, 0.5C, 1C, 2C, 5C, 10C, 15C and 20C rates, respectively. After 100 cycles, the as-prepared Li4Ti5O12 retains 99.6%, 96.9%, 98.8%, 89.3%, 90.4% and 89.0% of its initial discharge capacities at the 1C, 2C, 5C, 10C, 15C and 20C rates, respectively. [Copyright &y& Elsevier]

Abstract: We demonstrate an aqueous mixing technique to synthesize nano-micron Li4Ti5O12 by spray drying followed by solid-state calcination. The as-prepared materials are characterized by XRD, TG–DTA, SEM, TEM and electrochemical measurements. Well-crystallized Li4Ti5O12 with no impurity can be obtained at a relatively low calcined temperature (650°C) owing to the effect of nanoscale and uniform particles. Because of the rough and porous nano-micron spherical particles, the obtained Li4Ti5O12 shows excellent rate capability and cycle ability. The initial discharge capacities are 174.8, 170.5, 167.5, 165.3, 158.2, 152.1, 130.9 and 111.9mAhg−1 at the 0.1, 0.5, 1, 2, 5, 10, 15 and 20 C rates, respectively. After 100 cycles, the as-prepared Li4Ti5O12 retains 99.6%, 96.9%, 98.8%, 89.3%, 90.4% and 89.0% of its initial discharge capacities at the 1, 2, 5, 10, 15 and 20 C rates, respectively. [Copyright &y& Elsevier]

Abstract: We demonstrate a simple and novel approach for the synthesis of a kind of anatase TiO2 nanowires. The method is based on a hydrothermal method under normal atmosphere without using the complex Teflon-lined autoclave, high concentrations NaOH solution and long react time. The as-prepared materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The obtained anatase TiO2 nanowires show excellent performance. There is a potential plateau at 1.77 and 1.88V in the process of Li insertion and extraction, and the initial Li insertion/extraction capacities are 283 and 236mAhg−1 at the density of 20mAg−1, respectively. In the 20th cycle, the reversible capacities still remain about 216 and 159mAhg−1 at the current densities of 20 and 200mAg−1, respectively, and the coulombic efficiency is more than 98%, exhibiting excellent electrochemical performance. [Copyright &y& Elsevier]

Abstract: Spinel Li4Ti5O12 anode material is successfully synthesized by a solid-state method using lithium carbonate and titanium precursors which are prepared by the low cost industrial titanyl sulfate solution. The characters of H2TiO3 and TiO2 precursors are determined by TG/DTA and SEM methods. TG-DAT and EDS methods show that H2TiO3 can absorb sulphate ions which can be present as impurities. XRD method shows that the impure phases of Li2SO4 and rutile TiO2 appear in Li4Ti5O12 synthesized by H2TiO3. The formation of Li2SO4 is identified in thermodynamics during the process of calcination. Owing to the formation of Li2SO4 impurity, the capacity of the Li4Ti5O12 synthesized by H2TiO3 is low. One effective way that can tackle this problem is to remove the sulphur by calcining H2TiO3, after calcinations, the production will have a thermal treatment with Li2CO3. The obtained Li4Ti5O12 shows better electrochemical performance. The specific capacities can be increased by 20mAhg−1 at 0.1, 0.5 and 1C rates. [ABSTRACT FROM AUTHOR]