N, S co-doped activated carbon with porous architecture derived from partial poly (2, 2′-dithiodianiline) for supercapacitors

•The ASNC-600–800 was prepared with the N, S elements co-doped and developed porous structure.•The ASNC-600–800 showed a porous structure with a large surface area.•The ASNC-600–800 electrode materials showed high specific capacity of 500.10 F/g at a current density of 1A/g.•Symmetrical supercapacitor was assembled with an extended operating voltage window of 1.8 V in 1 M Na2SO4aqueous.•The symmetrical supercapacitor device possess the specific energy of 21.15 Wh/kg at specific power of 450 W/kg.