Carbon Encapsulated Hollow Co3O4 Composites Derived from Reduced Graphene Oxide Wrapped Metal–Organic Frameworks with Enhanced Lithium Storage and Water Oxidation Properties

Transition metal oxides have received great attention for boosting the performances for lithium-ion batteries and oxygen evolution reaction (OER). Here, hollow Co 3 O 4 nanoparticles encapsulated in reduced graphene oxide (rGO) ( h -Co 3 O 4 @rGO) were synthesized through a two-step annealing process of graphene oxide wrapped zeolitic imidazolate framework-67 (ZIF-67@GO) precursors. By taking advantage of the enhanced conductivity, high dispersity, high surface area, and unique hollow morphology derived from the GO-wrapped protecting annealing strategy, the as-synthesized h -Co 3 O 4 @rGO composite not only exhibits a reversible capacity as high as 1154.2 mAh g –1 at 500 mA g –1 after 100 cycles and high rate performance (746 mAh g –1 at 3000 mA g –1 ) but also displays superior OER performance with an overpotential of 300 mV to obtain 10 mA cm –2 .