Reed straw derived active carbon/graphene hybrids as sustainable high-performance electrodes for advanced supercapacitors

Reed straw-derived active carbon@graphene (AC@GR) hybrids were prepared by one-step carbonization/activation process using a mixture of reed straw and graphene oxide (GO) as raw materials and ZnCl2 as activation agent. The as-prepared hybrids exhibit high specific surface area in a range of 1971-2497 m(2) g(-1), abundant porosity, as well as excellent energy storage capability. The symmetric C//C supercapacitor using the hybrid obtained at 700 degrees C as electrodes demonstrates superior cycling durability, ca. 90 % retention after 6000 cycles at 2 A g(-1), and a high energy density of 6.12 Wh kg(-1) at a power density of up to 4660 W kg(-1) in 6 M KOH aqueous electrolyte. The excellent capacitive performance is attributed to the synergistic effect of AC and GR.