Niobium doped anatase TiO2 as an effective anode material for sodium-ion batteries

Sodium-ion batteries are considered to be a promising low-cost alternative to common lithium-ion batteries in the areas where specific energy is less critical. Among all the anode materials studied so far, TiO2 is very promising due to its low operating voltage, high capacity, nontoxicity, and low production cost. Herein, we present Nb-doped anatase TiO2 nanoparticles with high capacity, excellent cycling performance, and excellent rate capability. The optimized Nb-doped TiO2 anode delivers high reversible capacities of 177 mA h g(-1) at 0.1C and 108.8 mA h g(-1) at 5C, in contrast to 150.4 mA h g(-1) at 0.1C and only 54.6 mA h g(-1) at 5C for the pristine TiO2. The good performance is likely to be associated with enhanced conductivity and lattice expansion due to Nb doping. These results, in combination with its environmental friendliness and cost efficiency, render Nb-doped TiO2 a promising anode material for high-power sodium-ion batteries.