Ultrahigh-energy and stable supercapacitors based on intertwined porous MoO3–MWCNT nanocomposites

Nanocomposites of intertwined multi-walled carbon nanotubes (MWCNTs) and MoO3 nanowires were synthesized using a hydrothermal method. The intercalation of MWCNTs with MoO3 nanowires made them excellent materials for viable supercapacitors with high energy and power densities. The specific capacitance of the intertwined MoO3–MWCNTs nanocomposite reached 210 F g−1, and the energy density was improved greatly to 71.6 Wh kg−1 with a power density of 600 W kg−1 compared to those of pristine MWCNTs and MoO3 nanowires. The composite electrodes exhibited an excellent charge/discharge rate and long-term cyclic stability in terms of capacitance with an efficiency of more than 95% after 2000 cycles. These findings open up the possibility of intertwined MoO3–MWCNT composites being utilized in safe aqueous electrolyte (Na2SO4)-based high-voltage supercapacitors with high energy and power densities.

► Intertwined MWCNTs–MoO3 nanocomposites were synthesized using facile hydrothermal method.
► Intertwined MWCNTs–MoO3 nanocomposites have achieved capacitance of 210 F g−1.
► The capacitance value remained almost unchanged from 210 F g−1 to 200 F g−1 after 1000 cycles.
► The hybrid nanocomposite supercapacitor has high energy density up to 71.6 Wh kg−1.