Energy and cost-efficient nano-Ru-based perovskites/RGO composites for application in high performance supercapacitors.

Nano-Ru-based perovskites RGO are prepared simultaneously in presence of various A-metal salts (A = Sr, Ba or Ca salts) using two different methods for reaction initiation. No further calcination step is needed for the formation of well-defined perovskite structure. Graphene oxide (GO) is used as a fuel to prepare various Ru-based perovskites for the first time. The resulted low-Ru content nanocomposites are used as supercapacitor electrodes in a neutral electrolyte (1.0 M NaNO3). The results show that the specific capacitance of the resulted nanocomposites strongly depends on the method of their preparation as well as the type of A-site of the nanocomposites. Ru-based perovskites RGO nanocomposites that are prepared by combustion method show higher specific capacitance than those prepared by microwave irradiation. The maximum specific capacitance of Sr-, Ba- and Ca-RG-C composites at scan rate 2 mV s-1 are 564 (598 mF cm-2), 460 (487 mF cm-2) and 316 (336 mF cm-2) F g-1, respectively. This value is higher than our previous work using a physical mixture between the individually prepared RGO and SrRuO3. Lowest values for specific capacitance are obtained when using CaRuO3/RGO prepared using microwave-assisted method (Ca-RG-M). The resulted A-RG-nanocomposites show very high cycling stability and good specific capacitance compared to other Ru-based structures previously reported in the literature. A correlation is defined between the structure and specific capacitance of the nanocomposites. It is confirmed that the nanocomposite size, morphology and distribution over the RGO matrix influence the supercapacitor characteristics.