Cellulose-derived carbon nanofibers/graphene composite electrodes for powerful compact supercapacitors

摘要

Herein, we demonstrate a unique supercapacitor composite electrode material that is originated from a sustainable cellulosic precursor via simultaneous one-step carbonization/reduction of cellulose/graphene oxide mats at 800 \ub0C. The resulting freestanding material consists of mechanically stable carbon nanofibrous (CNF, fiber diameter 50\u2013500 nm) scaffolds tightly intertwined with highly conductive reduced graphene oxide (rGO) sheets with a thickness of 1\u20133 nm. The material is mesoporous and has electrical conductivity of 49 S cm\u22121, attributed to the well-interconnected graphene layers. The electrochemical evaluation of the CNF/graphene composite electrodes in a supercapacitor device shows very promising volumetric values of capacitance, energy and power density (up to 46 F cm\u22123, 1.46 W h L\u22121 and 1.09 kW L\u22121, respectively). Moreover, the composite electrodes retain an impressive 97% of the initial capacitance over 4000 cycles. With these superior properties, the produced composite electrodes should be the \u201clooked-for\u201d components in compact supercapacitors used for increasingly popular portable electronics and hybrid vehicles.