Anatase TiO2@C composites with porous structure as an advanced anode material for Na ion batteries

In this paper, we propose a facile strategy to synthesize the porous structure TiO2@C composites through a two-step method, in which the precursor of MIL-125(Ti) was firstly prepared by solvent thermal method and then calcined under inert atmosphere. When employed as anodes for Na ion batteries, TiO2@C composites can exhibit a superior cyclability with a reversible sodium storage capacity of 148 mAh g−1 at the current density 0.5 A g−1 after 500 cycles and an excellent rate performance with a capacity of 88.9 mAh g−1 even the current reached to 2.5 A g−1 due to the dispersion of anatase TiO2 throughout amorphous carbon matrix and the synergistic effect between the anatase TiO2 nanocrystals and carbon matrix, which can availably enhance the electric conductivity and alleviate the volumetric variation of TiO2 during the insertion/extraction process of Na+.