One-step construction of strongly coupled Co3V2O8/Co3O4/MXene heterostructure via in-situ Co-F bonds for high performance all-solid-state asymmetric supercapacitors

Co 3 V 2 O 8 /Co 3 O 4 /Ti 3 C 2 T x composite was easily synthesized via one-step succinct-operated hydrothermal process. The interconnected Co 3 V 2 O 8 /Co 3 O 4 nanowires network can in-situ grow and anchor on the surface of Ti 3 C 2 T x via the strong Co-F bonds and contribute tremendously to depress Ti 3 C 2 T x self-restacking. Profiting from the synergistically interplayed effect among the multiple interfaces and high conductivity of Ti 3 C 2 T x as well as outstanding stability of the as-designed nanostructure, the optimum Co 3 V 2 O 8 /Co 3 O 4 /Ti 3 C 2 T x electrode reaches a commendable specific capacitance (up to 3800 mF·cm −2 ), great rate capability (80% capacitance retention after 20-times current increasing), and preeminent cycling stability (95.4%/85.5% retention at 7000th/20,000th cycle). Moreover, the all-solid-state asymmetric supercapacitor based on Co 3 V 2 O 8 /Co 3 O 4 /Ti 3 C 2 T x and active carbon can deliver a high energy density of 84.0 μWh·cm − 2 at the power energy of 3.2 mW·cm −2 , and excellent cycling durability with 87.0% of initial capacitance retention upon 20,000 loops. This work provides a practicable pathway to tailor MXene-based composites for high-performance supercapacitor. Graphical abstract