Graphene-Carbon nanotube @ cobalt derivatives from ZIF-67 for All-Solid-State asymmetric supercapacitor

Highlights: • A graphene and carbon nanotube wrapped cobalt electrode (Gr-CNT@Co) was prepared. • The interconnected Gr-CNT@Co material shows excellent electrochemical performance. • Gr-CNT@Co//N-doped rGO all-solid-state asymmetric supercapacitor was fabricated. • The ASSC delivers a high energy density of 36.55 Wh kg⁻¹ at 685.3 W kg⁻¹. Metal-Organic Framework (MOF) materials attract increasing interest for their energy storage application by converting MOF into MOF derivatives. Herein, a graphene and carbon nanotube wrapped Cobalt derivatives (Gr-CNT@Co) electrode material is prepared by annealing the complex of ZIF-67 and graphene oxide. The as-prepared Gr-CNT@ Co shows an interconnected porous structure, a high specific surface (253.9 m²g⁻¹), and a high specific capacitance of 1108F g⁻¹ with high cycling stability. Furthermore, the constructed all-solid-state asymmetric Gr-CNT@Co// N-doped rGO device exhibits a high energy density of 36.55 Wh kg⁻¹ at 685.3 W kg⁻¹, as well as an excellent cycle capacitance retention (78%) after 6000 cycles at 1.5Ag⁻¹, which shows that Gr-CNT@Co is very promising electrode material for portable energy storage devices applications.