Sustained Lithium-Storage Performance of Hierarchical, Nanoporous Anatase TiO2 at High Rates: Emphasis on Interfacial Storage Phenomena

A hierarchical, nanoporous TiO2 structure is successfully prepared by a simple in situ hydrolysis method. Used as an anode material, it achieves a sustained high lithium storage performance especially at high charge/discharge rates due to its substantially high surface area. The material shows two different major storage modes: a) bulk insertion, and b) pseudo-capacitive interfacial storage, which is responsible for 64% of the total capacity. In order to kinetically emphasize the interfacial storage even further, we cycle the material directly at high rates, giving 302 mA h g(-1) and 200 mA h g(-1) of fully reversible discharge capacity at charge/discharge rates of 1 C and 5 C with very high cycle stability. We propose an overall view on the different Li insertion mechanisms of the high-surface-area nanoporous TiO2 and emphasize the importance of interfacial storage for electrode applications in Li-ion batteries.