Mesoporous cobalt monoxide nanorods grown on reduced graphene oxide nanosheets with high lithium storage performance

Graphical abstract: - Highlights: • Facile synthesis of mesoporous CoO NRs/rGO composite by a hydrothermal method. • The composite has an unique 1D porous nanorods/2D sheets hybrid nanostructure. • The CoO NRs/rGO composite shows excellent electrochemical performance as anode materials for Li-ion batteries. - Abstract: Graphene-based hybrid nanostructures could offer many opportunities for improved lithium storage performance. Herein, we report a facile synthesis of mesoporous CoO nanorods (CoO NRs) on a reduced graphene oxide (rGO) substrate by hydrothermal and calcination treatment. Transmission electron microscopy (TEM) investigation reveals that the CoO NRs with a diameter of 20–60 nm are tightly anchored on the surface of rGO sheets. Compared to pure CoO NRs, the CoO NRs/rGO composite shows higher lithium storage capacity and superior rate capability as anode materials for Li-ion batteries. The CoO NRs/rGO composite delivers an initial discharge capacity of 1452 mAh g⁻¹, and it can still remains 960 mAh g⁻¹ after 50 cycles at 0.1 A g⁻¹. After each 10 cycles at 0.1, 0.2, 0.5, and 1 A g⁻¹, the specific capacities of the composite are about 1096, 1049, 934 and 513 mAh g⁻¹, respectively. The enhanced electrochemical performance of the composite is closely related to its unique structure, such as 1D mesoporous morphology of CoO NRs and its tightly-contacting with rGO nanosheets, which could shorten the transport pathway for both electrons and ions, enhance the electrical conductivity and accommodate the volume expansion during prolonged cycling