Publication

Abstract : Abstract Energy storage technologies are sensitively dependent on electrode film quality, thickness and process scalability. In Li-ion batteries, using additive-free titania (TiO2) as electrodes, we sought to show the potential of spray pyrolysis-deposited nanoengineered films with thicknesses up to 135nbsp;μm exhibiting ultra-high areal capacities. Detailed electron microscopic characterization indicated that the achieved thick films are composed of highly crystalline anatase TiO2 particles with sizes on the order of 10–12nbsp;nm and porous as well. A 135nbsp;μm thick film yielded ultra-high areal and volumetric capacities of 3.7nbsp;mAhnbsp;cm−2 and 274nbsp;mAhnbsp;cm−3, respectively, at 1C rate. Also the present work recorded high Coulombic efficiency and good cycling stability. The best previously achieved capacities for additive-free TiO2 films have been less than 0.25nbsp;mAhnbsp;cm−2 and With additives, best reported areal capacity in the literature has been 2.5nbsp;mAhnbsp;cm−2 at 1C rate, but only with electrode thickness as high as 1400nbsp;μm. Formation of through-the-thickness percolation of Ti3+ conductive network upon lithiation contributed substantially for the superior performance. Spray pyrolysis deposition of nanoparticulate TiO2 electrodes have the potential to yield volumetric capacities an order of magnitude higher than the other processes previously reported without sacrificing performance and process scalability.