3D Flower-Petal-like CoCr-Layered Double Hydroxides Anchored on a 2D Vanadium Aluminum Carbide (V4AlC3) Substrate for High-Performance Extrinsic Supercapacitors

The uniquely integrated hybrid material, constituting of three-dimensional (3D) flower-petal-like CoCr-layered double hydroxides hybridized with a multilayered two-dimensional (2D) vanadium aluminum carbide (V₄AlC₃) substrate, by preserving the properties of each component owing to a synergistic effect, thereby improving the electrochemical performance. Herein, we have synthesized 3D flower-petal-like CoCr-LDH on a 2D V₄AlC₃ substrate nanocomposite via a hydrothermal synthesis route. The optimized CCVM-40 nanocomposite electrode exhibited hybrid charge storage with well-balanced capacitive performance, high rate capability, and charge transport as compared to CoCr-LDH. The nanocomposite of CoCr-LDH and V₄AlC₃ MAX can significantly enhance the electrochemical performance of pristine CoCr-LDH. The CoCr-LDH/V₄AlC₃ MAX nanocomposite displays a high specific surface area, an interconnected porous organ-like morphology, and intimate coupling between LDH nanosheets and the 2D layered V₄AlC₃ MAX. This unique architecture, along with strong interfacial interactions and synergistic effects between the layered V₄AlC₃ MAX and CoCr-LDH nanosheets, greatly improves electrical conductivity and increases the number of active sites accessible to the electrolyte. Moreover, the hybrid nanostructured composite prevents self-aggregation and restacking of the CoCr-LDH nanosheets onto V₄AlC₃ MAX, thereby assuring complete exposure of the active sites. The CCVM-40 nanocomposite demonstrates an excellent specific capacitance of 1375.9 F g^–1 at a scan rate of 2 mV s^–1, attributed to its unique hybrid nanostructure. Furthermore, the solid-state hybrid supercapacitor, fabricated using CCVM-40 as the battery-type electrode and activated carbon as the capacitive electrode, achieves a notable energy density of 85.41 W h kg^–1 at a power density of 1.1 kW kg^–1. Additionally, the hybrid supercapacitor device exhibits an outstanding capacitance retention rate of 90.8% after 8000 cycles at a current density of 6 A g^–1. Hence, it can be deduced from these exceptional results that additional research into these promising nanostructures with their excellent charge storage capabilities and unique microstructural traits is necessary for the development of next-generation energy storage devices.