One-step synthesis of SnO ₂ and TiO ₂ hollow nanostructures with various shapes and their enhanced lithium storage properties

A versatile one-step method for the general synthesis of metal oxide hollow nanostructures is demonstrated. This method involves the controlled deposition of metal oxides on shaped α-Fe ₂O ₃ crystals which are simultaneously dissolved. A variety of uniform SnO ₂ hollow nanostructures, such as nanococoons, nanoboxes, hollow nanorings, and nanospheres, can be readily generated. The method is also applicable to the synthesis of shaped TiO ₂ hollow nanostructures. As a demonstration of the potential applications of these hollow nanostructures, the lithium storage capability of SnO ₂ hollow structures is investigated. The results show that such derived SnO ₂ hollow structures exhibit stable capacity retention of 600-700 mAh g ^-1 for 50 cycles at a 0.2 C rate and good rate capability at 0.5-1 C, perhaps benefiting from the unique structural characteristics.