Ultrathin TiO2 rutile nanowires enable reversible Mg-ion intercalation

Abstract

• Novel structures for multi-valent ion battery. • The hydrothermal production of ultrathin TiO 2 nanowires. • Preferable intercalation of Mg 2+ ion into TiO 2 rutile nanowires. • The importance of nanostructure engineering to energy storage. Crystalline ultrathin TiO 2 nanowires with oriented configurations are promising for high-performance energy storage and conversion devices. In this work, we use hierarchical microspheres constructed from radially oriented single-crystalline TiO 2 nanowires as electrode materials for reversible Mg-ion intercalation. The obtained mesoporous TiO 2 nanowires deliver a capacity of 118 mA h g −1 at 20 mA/g current rate. The ultra small size of TiO 2 nanocrystalline is beneficial for reaction kinetics, enhance the bulk intercalation of Mg ions, which remarkably increases storage capacity of TiO 2 . The discharge capacity over 100 cycles remains 105.2 mA h g −1 , demonstrating the superiority of this material structure and its potential in magnesium ion batteries.