A N/S co-doped free-standing carbon electrode derived from waste facial masks for anti-freezing flexible quasi-solid-state supercapacitors.

A cost-effective N/S co-doped carbon cloth has been synthesized by pyrolysis of waste facial masks as robust free-standing electrodes with high capacitance for assembling anti-freezing flexible quasi-solid-state supercapacitors with high energy and good adaptability at low temperatures of -20 °C.