Fabrication of graphene-supported Zn-BTC with different morphologies and their supercapacitor performance

There has been considerable interest in supercapacitors because of their remarkable advantages, including their high power density, rapid charge–discharge rate, and long cycle life. Metal–organic frameworks (MOFs) have been extensively utilized in energy conversion and storage due to their large specific surface area and tunable pore structures. The poor conductivity of MOFs makes them unsatisfactory electrode materials for supercapacitors. This issue was addressed by synthesizing graphene-supported Zn-BTC metal–organic framework materials with different morphologies by combining ultrasonic oscillation with one-step solvothermal synthesis. It was found that the synthesized Zn-BTC material was uniformly anchored on wrinkled graphene nanosheets and that the specific capacitance was 201.3 C g−1 (at 1 A g−1), exceeding the specific capacitance of graphene-supported two-dimensional sheet-like Zn-BTC (152.6 C g−1), graphene-supported three-dimensional spherical Zn-BTC (139.6 C g−1), graphene (108.2 C g−1), and one-dimensional rod-shaped Zn-BTC (63.5 C g−1). Using graphene-supported, rod-shaped Zn-BTC as a basis for symmetric supercapacitors, a maximum energy density of 4.55 Wh kg−1 was achieved at 104.17 W kg−1 with specific capacitance retention of 93.26