Graphene-bonded and -encapsulated mesoporous TiO2 microspheres as a high-performance anode material for lithium ion batteries

Abstract

A facile procedure are developed to fabricate graphene-bonded and -enwrapped mesoporous anatase TiO2 microspheres (GMTMs) using graphene oxide (GO) and titanium glycolate microspheres (TGMs) as precursors without using any cross-linking reagents. Highly nanoporous TiO2 spheres are generated via in situ hydrolysis of the TGMs and then wrapped by GO nanosheets over their surface through covalent linkage during a reflux process. After hydrothermal treatment and calcination in an Ar atmosphere, the crystallization of TiO2 and the reduction of GO is significantly increased simultaneously. Electrochemical performance of the mesoporous TiO2 microspheres (MTMs) enwrapped with chemically-bonded graphene is greatly improved in terms of specific capacity, rate capability and cycle stability. The composite material shows a discharge capacity of 170 mA h g−1 at the 10 C rate, which is much higher than that of the pristine TiO2 microspheres (116 mA h g−1).