Crumpled Graphene-Molybdenum Oxide Composite Powders: Preparation and Application in Lithium-Ion Batteries

Crumpled graphene-MoO2 composite powders are directly prepared by means of spray pyrolysis and from a stable graphene oxide colloidal solution in the presence of Mo ions. The crumpled graphene-MoO2 composite powders are transformed into MoO3-based composite powders after post-treatment at 300 degrees C. The transmission electron microscopy and dot-mapping images of the post-treatment composite powders show uniform distribution of MoO3 nanocrystals in the crumpled graphene powders. The two typical D and G bands of graphene are observed at 1350 and 1590 cm(-1), respectively, in the Raman spectrum of the graphene-MoO3 composite. In addition, the crumpled graphene-MoO3 powders exhibit superior electrochemical behavior compared to that of pure MoO3 as an anode material for lithium-ion batteries. The initial discharge capacities of the graphene-MoO3 composite and bare MoO3 powders at a current density of 2 Ag-1 are 1490 and 1225 mAhg(-1), respectively. The capacity retention of the graphene-MoO3 composite is 87% after the first cycle, whereas that of bare MoO3 is 47%, as measured after 100 cycles. The reversible discharge capacity of the graphene-MoO3 composite decreases slightly from 1228 to 845 mAhg(-1) as the current density increases from 0.5 to 3 Ag-1.