Nanocrystalline Li4Ti5O12 (LTO) crystallizing in cubic spinel-phase has been synthesized by single-step-solution-combustion method in less than one minute. LTO particles thus synthesized are flaky and highly porous in nature with a surface area of 12 m2/g. Transmission electron micrographs indicate the primary particles to be agglomerated crystallites of varying size between 20 and 50 nm with a 3-dimensional interconnected porous network. During their galvanostatic charge−discharge at varying rates, LTO electrodes yield a capacity value close to the theoretical value of 175 mA h/g at C/2 rate. The electrodes also exhibit promising capacity retention with little capacity loss over 100 cycles at varying discharge rates together with attractive discharge-rate capabilities yielding capacity values of 140 mA h/g and 70 mA h/g at 10 and 100 C discharge rates, respectively. The ameliorated electrode-performance is ascribed to nano and highly porous morphology of the electrodes that provide short diffusion-paths for Li in conjunction with electrolyte percolation through the electrode pores ensuring a high flux of Li.

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Comprehensive analysis of the intranuclear territories and motion of budding yeast chromosome XII loci suggests that long-range chromosome architecture is mainly determined by the physical principles of polymers.

Nafion-silica composite membranes are fabricated by embedding silica particles as inorganic fillers in perfluorosulfonic acid ionomer by a novel water hydrolysis process. The process precludes the use of an added acid but exploits the acidic characteristic of Nafion facilitating an in situ polymerization reaction through a sol-gel route. The use of Nafion as acid helps in forming silica/siloxane polymer within the membrane. The inorganic filler materials have high affinity to water and assist proton transport across the electrolyte membrane of the polymer electrolyte fuel cell ͑PEFC͒ even under low relative humidity ͑RH͒ conditions. In the present study, composite membranes have been tested in hydrogen/oxygen PEFCs at varying RH between 100 and 18% at elevated temperatures. Attenuated total reflectance-Fourier transform infrared spectroscopy and scanning electron microscopy studies suggest an evenly distributed siloxane polymer with Si-OH and Si-O-Si network structures in the composite membrane. At the operational cell voltage of 0.4 V, the PEFC with an optimized silica-Nafion composite membrane delivers a peak power density value five times higher than that achievable with a PEFC with conventional Nafion-1135 membrane electrolyte while operating at a RH of 18% at atmospheric pressures. The polymer electrolyte fuel cell ͑PEFC͒ is an attractive power source for a variety of applications 1 due to its high efficiency and environment-friendly characteristics. The current PEFC technology utilizes perfluorosulfonic acid ͑PFSA͒ polymer membranes, e.g., Nafion, as electrolyte and hence is limited to low-temperature applications. In order to realize the optimum PEFC performance, the Nafion membrane needs to be fully wet as the proton conduction in Nafion relies on the dissociation of protons from the constituent SO 3 H groups in the presence of water.2 However, the performance of PEFCs is enhanced at elevated temperatures by improved kinetics of the cathode and anode reactions and the reduction in adsorption of poisoned species such as CO. [3][4][5][6] To this end, Nafion-composite membranes suitably modified with ceramic/inorganic fillers, namely SiO 2 , TiO 2 , ZrO 2 , etc., are widely used 7-13 to facilitate proton conductivity in the membranes at elevated temperatures even under low relative humidity ͑RH͒ conditions. Watanabe et al. 14 have employed modified Nafion membrane fabricated by incorporating nanosized particles of SiO 2 , TiO 2 , Pt, Pt-SiO 2 , and Pt-TiO 2 to alleviate the humidification requirements of PEFCs. When operated under low humidification, PEFCs with an alternative membrane reportedly exhibited lower ohmic drops in relation to Nafion. In situ platinum particulates with sorption of the water produced on the incorporated oxide fillers attribute such an improvement accompanied with suppression of hydrogen crossover. The benefits of these composite membranes appear to be in the steady operation of PEFCs at about 130°C due to the higher rigidity of the membranes in relation to commercial Nafion membra...