Interfacial synergistic regulation of MXene-composited nickel-cobalt double hydroxide for high-performance supercapacitors

Abstract

Nickel-cobalt double hydroxide is gaining significant interest due to its high theoretical specific capacitance. However, its tendency to agglomerate and low electrical conductivity present major challenges for its application. This study employed a one-step hydrothermal method to integrate exfoliated few-layer MXene materials with NiCo-LDH, facilitating the uniform vertical growth of NiCo-LDH nanosheets on the surface of the MXene, effectively minimizing agglomeration. Additionally, the interfacial synergy between MXene and NiCo-LDH enhances the transfer of electrons from NiCo-LDH to MXene, resulting in an electron-rich MXene and an oxygen vacancy-rich NiCo-LDH. Together, these characteristics significantly improve the electrochemical performance of the material at high current densities, achieving 7776 Wh kg−1 and 66.96 Wh k g−1 at 15 A g−1. After cycling 40,000 times, it retains an impressive capacity retention rate of 89.5%. These findings demonstrate that MXene materials effectively tackle the main challenges associated with NiCo-LDH, opening new possibilities for their application in electrode materials.