Double layers combined with MXene and in situ grown NiAl-LDH arrays on nickel foam for enhanced asymmetric supercapacitors

The application of layered double hydroxide (LDH) in energy fields has been limited to its low conductivity and easy agglomeration. In this paper, 3D nickel foam (NF) and transition metal carbide (Ti3C2Tx) layer were taken as the substrate to prepare the NiAl-LDH-based nanocomposites through an immersion and hydrothermal method. Due to the synergistic effect between two-dimensional MXene and LDH layers, the NiAl-LDH arrays on conductive substrate presented enhanced electrochemical performance. The results show that the specific capacity of NiAl-LDH/MXene double layers is 1600 F g−1 at 1 A g−1, which is superior to that of a simple NiAl-LDH layer grown on Ni foam (1203 F g−1). The specific capacity of NiAl-LDH/MXene still can maintain 78% after 3000 cycles at a current density of 10 A g−1. In addition, the energy density of asymmetric supercapacitor assembled with NiAl-LDH/MXene and active carbon is 27.6 Wh kg−1 at 255 W kg−1 power density. Therefore, the introduction of MXene interlayers in the composite propels the application prospect of LDH in energy storage devices.