Synthesis of Co3O4/Carbon Heteroaerogels with Ultrahigh Capacitance via Polyethyleneimine Intercalation of Co2BIM4 Nanosheets

The development of metal-organic frameworks (MOFs)-based supercapacitors have attracted intense concentration in recent years due to their regularly arranged porous and tunable pore sizes. However, the performance of the MOFs-derived supercapacitors is also low because of their poor electrical conductivity and rarely accessible active sites. In the present work, we developed a Co-MOF (namely Co2BIM4, BIM=benzimidazole) nanosheets derived Co3O4/nitrogen-doped carbon (Co2BIM4-Co3O4/NC) heteroaerogel as a novel supercapacitor electrode. The 3D Co2BIM4-Co3O4/NC heteroaerogels were obtained by directly intercalating polyethyleneimine (PEI) into the interlayers of Co2BIM4 nanosheets and following by carbonizing the resulting Co2BIM4/PEI composite. The Co2BIM4-Co3O4/NC electrode possessed 3D conductive framework with an overlapped hetero-interface and expanded interlayers, leading to fast and stable charge transfer/diffusion and an enhanced pseudocapacitance performance. Therefore, the Co2BIM4-Co3O4/NC electrode showed ultrahigh capacitance of 2568 F g(-1) at 1 A g(-1), 1747 F g(-1) at 10 A g(-1), and excellent long cycling time with a capacitance preservation of 92.7 % following 10000 cycles at 10 A g(-1), which is very promising for applications in supercapacitors and other energy storage devices.