Three-dimensional honeycomb composites consist of metal carbides and layered double hydroxides for high-performance supercapacitor electrode materials

To achieve excellent electrochemical performance and stability, a composite material based on metal carbides (MXene) and CoNiZn layered double hydroxides (LDHs) has been synthesized, which synergistically combines the high electrical conductivity of MXene with the high theoretical specific capacity of LDHs. The as-prepared three-dimensional honeycomb-structural MXene/CoNiZn LDH composites have excellent cycle stability with a capacitance retention rate of 87.8% after 100,000 cycles and outstanding electrochemical activity with a specific capacitance of 2044.9 F g−1 at a scan rate of 5 mV s−1. Furthermore, electrochemical impedance spectroscopy also shows a reduced internal resistance indicating that the honeycomb-porous structure facilitates electron transfer and ion diffusion. This study provides a feasible route to develop high-performance supercapacitor electrode materials. •The 3D CoNi LDH nanoarray on the surface of MXene nanosheets were prepared.•The gravimetric specific capacitance of 2044.9 F/g was achieved at 5 mV/s.•The capacitance retention rate was as high as 87.8% after 100,000 cycles at 1 A/g.