The present work demonstrates the usefulness of the soft-template directed approach in preparing mesoporous titanium dioxide and applying it in dye-sensitized solar cells (DSSCs). Mesoporous titanium dioxide with nanograins of dimension in the range, 16-20 nm were prepared through the soft-templating approach using various cationic surfactants such as octyl-, dodecyl-, cetyl trimethylammonium bromide with different surfactant compositions and titania precursor concentrations. As-synthesized mesoporous titanium dioxide samples were characterized by TGA, PXRD, FESEM, HRTEM and surface area measurements, used as photo-electrode material in DSSCs. Under global AM 1.5 solar irradiation, the best photovoltaic performance of 7.5% with a short circuit photocurrent density of 14.2 mA/cm À2 , an open circuit voltage of 748 mV, and a fill factor of 70.83% were obtained for the DSSC using a film of mesoporous TiO 2 synthesized from the cetyl trimethylammoniumbromide surfactant. In contrast, the use of commercial titania powder P25 resulted in an efficiency of 5.0% under similar conditions. The structural and morphological merits of these template-directed materials will be especially addressed in comparison with their traditional bulk forms.

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The ability of Li-ion batteries to deliver high power and energy is accompanied by heat generation and thermal runaway resulting in detrimental effects. While capacity fade and the consequential reduced cycle life are prime issues in Li-ion batteries, the impending need for safety in handling them and need for safe failure in off-nominal conditions are critically important. In this contribution, we report heat generation in Li-ion batteries containing cathodes such as NCA (LiNi 0.8 Co 0.15 Al 0.05 O 2 ), NMCs (LiNi 0.2 Mn 0.2 Co 0.6 O 2 ; LiNi 0.6 Mn 0.2 Co 0.2 O 2 ) against graphite anode. The total heat generation is determined using an Accelerating Rate Calorimeter and the reversible heat generation is determined using entropic coefficient measurement. The internal resistance contributing to the irreversible heat generation is estimated by AC impedance studies. Further, variation in the components of internal resistance across different States of Charge determined by fitting an equivalent circuit model is presented. The cell skin temperature recorded at low C rates in 18650-type full cells is correlated with the entropic coefficient in corresponding half-cells to understand thermodynamics during phase transition in cathodes and structural transformation in graphite. The findings from the experiments are helpful in the electrochemical and thermal modeling of Li-ion batteries which in turn would aid better design of thermal management systems.