Rationally designed hierarchical TiO₂@Fe₂O ₃ hollow nanostructures for improved lithium ion storage

Hollow and hierarchical nanostructures have received wide attention in new-generation, high-performance, lithium ion battery (LIB) applications. Both TiO₂ and Fe₂O₃ are under current investigation because of their high structural stability (TiO₂) and high capacity (Fe₂O₃), and their low cost. Here, we demonstrate a simple strategy for the fabrication of hierarchical hollow TiO₂@Fe ₂O₃ nanostructures for the application as LIB anodes. Using atomic layer deposition (ALD) and sacrificial template-assisted hydrolysis, the resulting nanostructure combines a large surface area with a hollow interior and robust structure. As a result, such rationally designed LIB anodes exhibit a high reversible capacity (initial value 840 mAh g ^-1), improved cycle stability (530 mAh g^-1 after 200 cycles at the current density of 200 mA g^-1), as well as outstanding rate capability. This ALD-assisted fabrication strategy can be extended to other hierarchical hollow metal oxide nanostructures for favorable applications in electrochemical and optoelectronic devices.