A flexible graphene/multiwalled carbon nanotube film as a high performance electrode material for supercapacitors

► A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film fabricated by flow-directed assembly and hydrazine to reduce. ► The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets. ► The freestanding GN/MWCNT film has a potential application in flexible energy storage devices.