Synergistic coupling of NiVAl-layered double hydroxide with few-layered Ti3C2Tx–MXene nanosheets for superior asymmetric supercapacitor performance

Abstract

Layered double hydroxides (LDHs) are promising energy materials due to their considerable theoretical capacity, but they also suffer from inherent poor electrical conductivity and agglomeration problems. In this study, a composite electrode material with a unique structure was synthesized by in situ growth of nanoscale NiVAl-LDH on the surface of few-layered Ti₃C₂T_x–MXene. The strong interfacial connection and enhanced electronic coupling between the two components enhance the structural stability and electrical conductivity of the material, significantly enhancing its redox kinetics. Moreover, this composite structure effectively prevents the aggregation and restacking of Ti₃C₂T_x–MXene and NiVAl-LDH nanosheets, ensuring the complete exposure of active sites. Demonstrating exceptional electrochemical capabilities, the composite electrode showcases a distinct capacitance of 186.7 mA h g⁻¹ at a current density of 1 A g⁻¹. Furthermore, it maintains an impressive 84.7% of its capacitance after enduring 5000 charge–discharge cycles at a high current density of 10 A g⁻¹. The assembled asymmetrical supercapacitor device demonstrates a respectable energy density of 51.6 W h kg⁻¹ at a power density of 800.0 W kg⁻¹, as well as excellent cycling stability (89.1% capacitance retention after 10 000 cycles at 10 A g⁻¹).