Enhanced supercapacitive performance of nickel-based metal–organic framework/reduced graphene oxide composite

Metal–organic frameworks (MOFs) are crystalline porous materials composed of central metal ions coordinated to organic ligands, forming tunable frameworks. Due to their excellent textural properties and superior mechanical and thermal stability, pristine MOFs have been utilised as electrode materials for electrochemical capacitors. Nevertheless, the limited electrical conductivity negatively affects their rate performance. Herein, we report the enhanced capacitance properties of Ni-based MOF/rGO composite prepared by a facile in situ method with a low loading level of rGO. The microstructural studies revealed that the presence of the GO in the reaction bath not only influences the morphology of MOF but also facilitates the transformation of the nickel salt precursor into the final product. The optimised Ni-MOF/rGO2.0 electrode exhibited a specific capacity of 527 C g⁻1 at 6 A g⁻1 as compared to pristine Ni-MOF (402 C g⁻1). Furthermore, Ni-MOF/rGO2.0 electrode demonstrated a superior rate capability by retaining 38.11% of its initial specific capacity when the current density is increased to 20 A g−1. The improved capacitance performance of Ni-MOF/rGO2.0 is attributed to the synergistic interaction between the conductive rGO network and the redox-active Ni-MOF, which facilitates faster charge transport and optimum redox activity of Ni-MOF.