Rational design of NiCoAl-LDH/Ti3C2Tx MXene with carbon based hybrid electrodes: Experimental and theoretical insights into high-performance asymmetric supercapacitors

초록

Layered double hydroxides (LDHs) have gained significant attention as active materials for high-performance supercapacitors due to good theoretical capacitance, excellent structural characteristics, remarkable redox activity, and environmental sustainability. Throughout this study, we developed a three-dimensional (3D) interconnected NiCoAl-LDH/MXene/CNT (NCA-MX-T) composite through a simple one-step hydrothermal approach. In this architecture, nanoflower-like NiCoAl-LDHs are vertically and uniformly anchored onto conductive MXene nanosheets, while carbon nanotubes (CNTs) form a conductive bridge across the structure. As a result of this optimized structure and composition, the NCA-MX-T electrode delivers capacitance of 984.8 F g-1 at 0.5 A g-1 with admirable capacitance retaining of 99.4% and coulombic efficiency of 99.2% after 6000 cycles. Additionally, an asymmetric supercapacitor (ASC) device was assembled with NCA-MX-T and activated carbon (AC) as the positive and negative electrode, respectively. The fabricated NCA-MX-T//AC device unveiled an energy density of 44 Wh kg-1 and 749.2 W kg-1 of power density, while sustaining 76.4% capacitance retention and 98.6% coulombic efficiency over 10,000 cycles. These findings highlight the potential of 3D interconnected hybrid structures in enhancing electrochemical performance and provide a valuable strategy for designing next generation energy storage devices.

키워드