Nanocrystalline ruthenium oxide dispersed Few Layered Graphene (FLG) nanoflakes as supercapacitor electrodes

Abstract

Significant enhancement in supercapacitor performance was achieved via the synthesis of nanocrystalline RuO2 on vertically aligned Few Layered Graphene (FLG) nanoflakes, synthesized on bare n-type heavily doped silicon substrates by microwave plasma chemical vapour deposition. The RuO2 nanoparticles (diameter <2 nm) were deposited using a combination of low base pressure radio frequency magnetron sputtering and subsequent electrochemical cycling in acidic media. The well-dispersed RuO2 nanoparticles on FLGs achieve a specific capacitance of the order of 650 F g−1. The specific capacitance of RuO2–FLGs is significantly higher than pristine sputtered RuO2 (∼320 F g−1) and FLGs (∼6 F g−1) indicative of the synergistic effect between the FLGs and RuO2. In addition, the fabricated RuO2–FLG supercapacitors show excellent cycling capability with approximately 70% retention of initial specific capacitance over 4000 cycles at high charging–discharging rates of 500 mV s−1. The superior electrochemical performance is attributed to the good electronic conductivity of the FLGs as well as high utilization of well-dispersed RuO2 nanoparticles on FLGs.