Porous cake-like TiO2 derived from metal-organic frameworks as superior anode material for sodium ion batteries

Abstract Porous cake-like TiO 2 was prepared simply by annealing Ti-based metal-organic frameworks templates. The morphology, structure and electrochemical performance of porous TiO 2 were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption, galvanostatic charge/discharge test, cyclic voltammetry and electrochemical impedance spectroscopy. When used as an anode for sodium ion batteries, porous TiO 2 exhibits a maximum charge capacity of 250 mAh g −1 after 50 cycles at a current density of 50 mA g −1 and delivers a remarkably stable reversible capacity of 173 mA g −1 after 2500 cycles even at a high current density of 1 A g −1 . The excellent electrochemical performance is attributed to the unique porous structure and suitable pore size of porous TiO 2 .