Three-dimensional porous MXene/layered double hydroxide composite for high performance supercapacitors

In this work, an exfoliated MXene (e-MXene) nanosheets/nickel-aluminum layered double hydroxide (MXene/LDH) composite as supercapacitor electrode material is fabricated by in situ growth of LDH on e-MXene substrate. The LDH platelets homogeneously grown on the surface of the e-MXene sheets construct a three-dimensional (3D) porous structure, which not only leads to high active sites exposure of LDH and facile liquid electrolyte penetration, but also alleviates the volume change of LDH during the charge/discharge process. Meanwhile, the e -MXene substrate forms a conductive network to facilitate the electron transport of active material. The optimized MXene/LDH composite exhibits a high specific capacitance of 1061 F g⁻¹ at a current density of 1 A g⁻¹, excellent capacitance retention of 70% after 4000 cycle tests at a current density of 4 A g⁻¹ and a good rate capability with 556 F g⁻¹ retention at 10 A g⁻¹.