2D nanoscale oxides have attracted a large amount of research interest due to their unique properties. Here, a facile synthetic approach to prepare graphene-mimicking, porous 2D Co3O4 nanofoils using graphene oxide (GO) as a sacrificial template is reported. The thermal instability of graphene, as well as the catalytic ability of Co3O4 particles to degrade carbon backbones, allow the fabrication of porous 2D Co3O4 nanofoils without the loss of the 2D nature of GO. Based on these results, a graphene mimicking as a route for large-area 2D transition metal oxides for applications in electrochemical energy storage devices is proposed. As a proof of concept, it is demonstrated that graphene-like, porous 2D Co3O4 nanofoils exhibit a high reversible capacity (1279.2 mAh g(-1)), even after 50 cycles. This capacity is far beyond the theoretical capacity of Co3O4 based on the conversion mechanism from Co3O4 to Li2O and metallic Co.