In situ synthesis of M (Fe, Cu, Co and Ni)-MOF@MXene composites for enhanced specific capacitance and cyclic stability in supercapacitor electrodes

•Electrochemical performance was enhanced on the in situ synthesized MOF@MXene electrodes.•Morphology regulation was achieved through in-situ composition of 3D MOFs on 2D MXene.•Excellent specific capacitance of 1160.5 F g−1 at 1 A/g was obtained on Ni-MOF@MX 2.•Synergistic effects between MOF and MXene were responsible for the excellent performance. In this study, an in situ method was developed to synthesize a series of uniform 3D MOFs (Fe-, Cu-, Co-, Ni)-BTC@2D MXene (Ti3C2Tx) composites, and the experimental results show that a typical sample of Ni-MOF@MX 2 exhibits the highest specific capacitance of 1160.5 F·g−1 and 736 F·g−1 at a current density of 1 A·g−1 and 20 A·g−1, respectively, which is 2.3 times higher than the value of 320 F·g−1 at a current density of 20 A·g−1 on the bare Ni-MOF, and particularly maintains significant cyclic stability after 10,000 cycles at a high current density of 20 A·g−1. The improved electrochemical performance is ascribed to the synergistic interaction between layered MXene and MOFs, which were evidenced by experiments and theoretical calculations. The Ni-MOF@MX 2//AC asymmetric supercapacitor (ASC) device demonstrates a maximum energy density of 48.2 Wh kg−1 at 750 W kg−1. It retains 94 % capacity after 10,000 cycles. Moreover, the value still maintained at 23.3 Wh·kg−1 when elevating power density to 15000 W·kg−1. This indicates that the obtained MOF@MXene composites are probably alternative materials for supercapacitor electrodes in energy storage.