Flexible quasi-solid-state SnO2/CNT supercapacitor processed by a dc-pulse nitrogen atmospheric-pressure plasma jet

•Atmospheric pressure plasma jet (APPJ) is used to sinter SnO2/CNT nanocomposites.•APPJ-sintered SnO2/CNT nanocomposites are used for electrodes of supercapacitors.•Optimized APPJ sintering time is only 15 s.•The best specific capacitance achieved is ∼4.42 mF cm−1 (under bending).•The capacitance retention rate is 98.3% after 1000 cycles (under bending).

This study investigates flexible quasi-solid-state SnO2/CNT nanocomposite supercapacitors fabricated using a dc-pulse nitrogen atmospheric-pressure plasma jet (APPJ). The optimal APPJ processing time is merely 15 s. Cyclic voltammetry (potential scan rate = 2 mV/s) shows an areal capacitance of 3.86 mF/cm2 when flat and 4.42 mF/cm2 under bending (bending radius R = 0.55 cm), indicating good functionality under flexing. The capacitance retention rate is 98.3% as evaluated after a 1000-cycle cyclic voltammetry test under bending (R = 0.55 cm), suggesting good operational stability.