From paper to paper-like hierarchical anatase TiO ₂ film electrode for high-performance lithium-ion batteries

A paper-like self-standing film electrode composed of hierarchical mesoporous anatase TiO ₂ was designed and prepared through a facile route of filter paper templating in combination with an additional deep hydrolysis treatment process. The specific surface area of hierarchical mesoporous TiO ₂ increased to 155.6 m2 g-1 compared to the sample without the additional deep hydrolysis, which is only 16.0 m2 g-1. The results are consistent with a simple model of sphere stacking which suggests that the rich mesopores were from the void space created by the TiO ₂ stacking. By applying such film as binder-free electrode in lithium-ion batteries (LIBs), good rate performance was demonstrated, and the capacity was still 100 mA h g-1 even at the high rate of 20 C. The contributions of Li+ insertion/extraction reaction and capacitive effect on the capacities were investigated by cyclic voltammetry and calculation. With the sweep rate increased from 0.1 to 10 mV s-1, the contributions of capacitive effects increased from 46% to 88% of the total capacities. The uniquely architectural TiO ₂ film electrode showed excellent cycling performance at high rate of 10 C through 400 cycles. It highly promises as a new anode for thin-film batteries with versatile application fields.