Integrated NiCo2-LDHs@MXene/rGO aerogel: Componential and structural engineering towards enhanced performance stability of hybrid supercapacitor

Abstract To enhance the electrochemical performance of MXene-based materials for energy storage devices, the componential modification related to the electrode capacity and the structural engineering related to the electrode stability are general strategies. Herein, a well-designed three-dimensional (3D) MXene-based aerogel (NiCo2-LDHs@MXene/rGO) on composition and structure is constructed by integrating MXene, NiCo2-LDHs, and reduced graphene oxide via a two-step method including hydrothermal and wet chemical techniques. This aerogel exhibits ultra-light nature, high theoretical capacity of LDHs, unblocked ion/electron channels of hierarchical structure, and good electrical conductivity of MXene and rGO networks, contributing to outstanding energy and power density, favorable capacity loss, and excellent stability as battery-type cathode material for supercapacitor. Most importantly, this aerogel delivers a remarkable specific capacity of 332.2 mAh g−1 at 1 A g−1 and a good durability of 87.5% after 5000 cycles at 5 A g−1 in a three-electrode system. Furthermore, a typical hybrid supercapacitor (HSC) device fabricated with NiCo2-LDHs@MXene/rGO as the cathode and MXene/rGO as the anode (NiCo2-LDHs@MXene/rGO//MXene/rGO) provides a superior energy density of 65.3 Wh kg−1 at a power density of 700 W kg−1, and maintains the capacity retention rate of 92.8% after 10,000 cycles at 5 A g−1. This work supplies a promising strategy to prepare MXene-based electrodes for assembling high-performance and low-cost energy storage devices.