Enhanced electrochemical performance of TiO2 by Ti3+ doping using a facile solvothermal method as anode materials for lithium-ion batteries

A facile method has been developed to synthesize Ti3+-doped TiO2 nanoparticles as high-performance anode materials for Li-ion batteries. After reducing some Ti4+ ions to Ti3+ ions with zinc powders in TiCl4 solution, Ti3+-doped TiO2 was synthesized by solvothermal methode. The obtained Ti3+-doped TiO2 nanoparticles are relatively uniform and better dispersed with an average size of 30 nm. Great improvement of the electrochemical performance was obtained by Ti3+-doping comparing with the pure TiO2. The Ti3+-doped TiO2 nanoparticles prepared at the Zn:Ti molar ratio of 4% are able to deliver a reversible capacity of 202.1 mAh g−1 at a current density of 100 mA g−1 and exhibit superior high-rate discharge/charge capability and cycling stability at the current density up to 3000 mA g−1 in a half cell configuration. The improved reversible capacity and rate capability could be ascribed to the presence of Ti3+, which improves the electrical conductivity and reduces the charge transfer resistance of the TiO2 electrode.