Ru and Os based new electrode for electrochemical flow supercapacitors

Here, we propose by means of a scalable and one-step approach, an efficient procedure for the synthesis of a multifunctional RuOsOx/G supercapacitor electrode material. Firstly, the synthesized material was extensively characterized: XRD, SEM and TEM images showed the existence of a quaternary nanostructure comprising RuO2and OsO2and metal inclusions, supported on graphene. Secondly, the capacitance performance of the synthesized sample was tested through cyclic voltammetry (CV) and galvanostatic charge and discharge (GCD) tests in a slurry flowable electrode configuration. RuOsOx/G shows very high specific capacitance (Csp) values: 729 F/g at 1 A/g and 718 F/g at 10 mV/s. Cspremains 627.3 F/g at 200 mV/s, therefore proving an excellent capacitance retention (∼90%). The capacitance evaluated on the bases of the two oxides weight is ∼1300 F/g, which is one of the highest Cspvalues among the reported in literature thus far. Moreover, the material exhibits a remarkable long-term stability: 98.5% of the initial capacitance was retained after 25,000 cycles at 20 A/g and the Coulombic efficiency is equal to 100%.