Microwave-assisted synthesis of mesoporous Co3O4 nanoflakes for applications in lithium ion batteries and oxygen evolution reactions.

Mesoporous Co3O4 nanoflakes with an interconnected architecture were successfully synthesized using a microwave-assisted hydrothermal and low-temperature conversion method, which exhibited excellent electrochemical performances as anode materials in lithium ion batteries and as catalysts in the oxygen evolution reaction (OER). Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) observations showed the unique interconnected and mesoporous structure. When employed as anode materials for lithium ion batteries, mesoporous Co3O4 nanoflakes delivered a high specific capacity of 883 mAh/g at 0.1C current rate and stable cycling performances even at higher current rates. Post-mortem analysis of ex situ FESEM images revealed that the mesoporous and interconnected structure had been well maintained after long-term cycling. The mesoporous Co3O4 nanoflakes also showed both OER active properties and good catalytic stability. This could be attributed to both the stability of unique mesoporous structure and highly reactive facets.