Hybrid of porous cobalt oxide nanospheres and nitrogen-doped graphene for applications in lithium-ion batteries and oxygen reduction reaction

•A complex precursor is developed from graphite oxide, Co2+ and melamine resin (MR).•Hybrid of porous Co3O4 nanospheres and N-doped graphene (Co3O4/NG) is achieved.•MR is beneficial to promote uniform N-doping and distribution of Co3O4.•The Co3O4/NG hybrid exhibits superb Li-ion storage performances.•The Co3O4/NG hybrid shows excellent catalytic activity toward oxygen reduction.

A new single-source precursor has been developed from the hydrothermal reaction of graphite oxide (GO), melamine resin (MR) monomers, and CoCl2 to prepare a sandwich-like hybrid of ultrathin nitrogen-doped graphene (NG) sheets and porous Co3O4 nanospheres (Co3O4/NG). This unique structure endows the Co3O4/NG hybrid with large surface area and enhanced electrochemical performances as both anode material for Li-ion batteries and electrocatalyst for oxygen reduction reaction (ORR). As an anode material, it exhibits high reversible capacity, excellent cycling stability and rate performance (1236 and 489 mAh g−1 over 200 cycles at 0.1C and 2C, respectively; 371 mAh g−1 at 5C). As an ORR electrocatalyst, it shows superior catalytic activity and high selectivity for the four-electron reduction pathway compared to the bare Co3O4 and NG alone. Moreover, the Co3O4/NG hybrid is insensitive to methanol, and is much more stable than Pt/C catalyst over long term operation.

Graphical abstractA new single-source precursor was developed from the hydrothermal reaction of graphite oxide, melamine resin monomers and CoCl2 to prepare a sandwich-like Co3O4/NG hybrid consisted of ultrathin nitrogen-doped graphene (NG) sheets and porous Co3O4 nanospheres. The Co3O4/NG hybrid possessed hierarchal pores, large surface area, high conductive network, and thus exhibited enhanced electrochemical performances as anode materials for Li-ion batteries and electrocatalysts for oxygen reduction reaction.Figure optionsDownload full-size imageDownload as PowerPoint slide