Graphene frameworks supported cobalt oxide with tunable morphologies for enhanced lithium storage behaviors

Three-dimensional hybrids of cobalt oxide (Co 3 O 4 ) and graphene frameworks are fabricated via a facile hydrothermal self-assembly process. By adjusting the time of the hydrothermal treatment, the morphologies of the Co 3 O 4 components can be modified from rods to nanoparticles, which further manifest influences on the electrochemical performance of the hybrids. As the anode in lithium-ion battery, the hybrid loaded with spherical Co 3 O 4 nanoparticles exhibits the highest reversible capacity of 1148 mA h g −1 at 100 mA g −1 for 100 cycles among the three samples. Even at a high current density of 5000 mA g −1 , its reversible capacity is still kept at 600 mA h g −1 , outperforming the reported hybrids of Co 3 O 4 and graphene.