Increasing S dopant and specific surface area of N/S-codoped porous carbon by in-situ polymerization of PEDOT into biomass precursor for high performance supercapacitor

•N/S codoped porous carbon (NSPC) is cost efficiently synthesized.•Higher S content and larger specific surface area are introduced by PEDOT.•The NSPC (PC-600) shows excellent reversible specific capacitance.•The symmetric supercapacitor delivers high energy density of 30.60 Wh kg−1.