TiO_2/石墨烯复合材料的制备与电化学性能研究

Synthesis and characterization of TiO_2/graphene composite

通过一种简易的水热法制备了TiO2纳米管，石墨烯复合材料（简称TNG）。采用XRD和SEM表征了材料的结构与形貌，并利用恒流充放电测试、循环伏安测试（CV）等手段对材料的电化学性能进行了研究。结果表明：在合成的TNG中，TiO2纳米管分布于石墨烯片层上，其纳米管的管径为50～100nm。在电流密度为10mA／g时，所制TNG的首次充放电可逆比容量为366mAh／g。即使是在1000mA／g的电流密度下，经过100次循环充放电后，TNG复合材料的可逆比容量仍有156mAh／g，库仑效率达到98．3％。合成的TNG具有良好的高倍率循环性能，适合应用于高倍率和大功率锂离子电池。

TiO2/graphene composites （term as TNG） were synthesized by a facile hydrothermal process. The structure and morphology were characterized by X-ray diffraction and scanning electron microscopy. Their electrochemistry performances were tested through cyclic voltammetry and constant current discharge/charge tests. The result shows that the TiO2 nanotubes in the TNG disperse onto the graphene sheets and the diameter of the nanotubes is 50-100 nm. The initial reversible specific capacity of the prepared TNG is 366 mAh/g at the current density of 10 mA/g. The composites exhibit good high-rate reversible specific capacity of 156 mAh/g and the coulombic efficiency of 98.3% after 100 cycles at rate of 1 000 mA/g. The excellent high-rate cycle performance makes TNG an ideal anode material for high-power, high-rate application of lithium ion batteries.