Nanowires-Assembled TiO 2 Nanorods Anchored on Multilayer Graphene for High-Performance Anodes of Lithium-Ion Batteries.

Multilayer graphene (MLG) prepared via ultrasonic exfoliation has many advantages such as its low-cost and defect-free nature, high electronic conductivity, and large specific surface area, which make it an apt conductive substrate for TiO 2 composites. To synthesize graphene/TiO 2 hybrids, traditional methods that greatly depend on the chemical bond of oxygen-containing functional groups on graphene with titanium cations are not applicable due to the absence of these functional groups on MLG. In this work, a facile chemical method is developed to directly deposit TiO 2 on the MLG surface without the introduction of chemically active groups. With this method, four types of TiO 2 materials, that is pure anatase TiO 2 nanoparticles, a mixture of anatase TiO 2 nanoparticles and rutile TiO 2 nanoflowers, pure rutile TiO 2 nanoflowers, and pure rutile TiO 2 nanorods, are homogeneously anchored on the MLG surface by controlling the amount of HCl in the reactant. Interestingly, the rutile TiO 2 nanorods in the TiO 2 /MLG composite are assembled by many TiO 2 nanowires with an ultra-small diameter and ultra-long length, which provides a better synergetic effect for high performances as LIB anodes than other composites. A specific capacity of 631.4 mAh g -1 after 100 cycles at a current density of 100 mA g -1 is delivered, indicating it to be a valuable LIB anode material with low cost and high electrochemical performances.