Hydrated ruthenium dioxides @ graphene based fiber supercapacitor for wearable electronics

Fiber supercapacitor (FSC), with the advantages of high power density and ability to be knitted into arbitrary shapes, serves as an ideally energy storage of wearable electronics. Here, we report a high specific capacitance and mechanical strength fiber supercapacitor via synthesizing ruthenium dioxide hydrate (RuO2·xH2O) @graphene in situ on flexible commercial carbon fibers. The typical “cracked mud”-like RuO2·xH2O @graphene uniformly wrap around the surface of the carbon fibers by the vapor-phase hydrothermal method. Meanwhile, Graphene plays a role in linking every two chapped chips of RuO2·xH2O, increasing the electronic conductivity and mechanical strength of the electrode. The fiber electrode exhibits high specific capacitance of 210.14 F cm−3 (0.42F cm−2 and 10.56 mF cm−1). Furthermore, the solid-state symmetric supercapacitor is fabricated with H3PO4/Poly(vinyl alcohol) as electrolyte and displays excellent cycling stability with 98.40% of the initial capacitance after 50000 continuous charging/discharging cycles, as well as good mechanical stability with 96.10% of the initial capacitance after 2000 continuous bending cycles. With merits of flexibility, high specific capacitance and cyclic/mechanical stability, the RuO2·xH2O @graphene carbon fiber enables to knit into any designed shape into energy textiles used as the energy storage module for wearable electronics.