Enhanced electrochemical performance of TiO_2 by Ti~(3+) doping using a facile solvothermal method as anode materials for lithium-ion batteries

摘要

A facile method has been developed to synthesize Ti~(3+)-doped TiO_2 nanoparticles as high-performance anode materials for Li-ion batteries. After reducing some Ti~(4+) ions to Ti~(3+) ions with zinc powders in TiCl_4 solution, Ti~(3+)-doped TiO_2 was synthesized by solvothermal methode. The obtained Ti~(3+)-doped TiO_2 nanoparticles are relatively uniform and better dispersed with an average size of 30 nm. Great improvement of the electrochemical performance was obtained by Ti~(3+)-doping comparing with the pure TiO_2. The Ti~(3+)-doped TiO_2 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 Ti~(3+), which improves the electrical conductivity and reduces the charge transfer resistance of the TiO_2 electrode.