Influence of Mesoporosity and Carbon Electronic Wiring on Electrochemical Performance of Anatase Titania

Abstract

The combined benefits of mesoporosity and in situ grown conductive amorphous carbon on lithium storage capacity of anatase TiO2 are discussed here. Micron-sized anatase TiO2 spheres with equal amount of carbon but different degree of mesoporosity and normal mesoporous TiO2 are synthesized by solvothermal and sol-gel methods respectively. While the specific surface areas were 80, 35 and 85 m2 g−1 respectively for mesoporous carbon-TiO2 sphere, carbon-TiO2 sphere and mesoporous TiO2, the primary size of the grains constituting the micrometer sized spheres was ~11 nm. The electrochemical lithium stored by all synthesized TiO2 materials show strong dependency on mesoporosity and carbon. Mesoporous carbon-TiO2 sphere exhibited a first discharge cycle capacity of 334 mAh g−1 at current rate of 66 mAg−1, whereas carbon-TiO2 sphere and mesoporous TiO2 stored 120 and 270 mAh g−1 respectively. Demonstration of high lithium storage capacity and good cyclability in mesoporous carbon-TiO2 sphere is attributed to the synergy of mesoporosity and in situ grown carbon in the formation of an effective percolation network for the conducting species (Li+/e−) around TiO2 nanoparticles.