Ultrathin Anatase TiO₂ Nanosheets Embedded with TiO₂‐B Nanodomains for Lithium‐Ion Storage: Capacity Enhancement by Phase Boundaries

A new form of TiO 2 microspheres comprised of anatase/TiO 2 ‐B ultrathin composite nanosheets has been synthesized successfully and used as Li‐ion storage electrode material. By comparison between samples obtained with different annealing temperatures, it is demonstrated that the anatase/TiO 2 ‐B coherent interfaces may contribute additional lithium storage venues due to a favorable charge separation at the boundary between the two phases. The as‐prepared hierarchical nanostructures show capacities of 180 and 110 mAh g −1 after 1000 cycles at current densities of 3400 and 8500 mA g −1 . The ultrathin nanosheet structure which provides short lithium diffusion length and high electrode/electrolyte contact area also accounts for the high capacity and long‐cycle stability.