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

Ahmed Galal; Hagar K Hassan; Nada F Atta; Timo Jacob

doi:10.1016/j.jcis.2018.12.018

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

J Colloid Interface Sci. 2019 Mar 7:538:578-586. doi: 10.1016/j.jcis.2018.12.018. Epub 2018 Dec 5.

Authors

Ahmed Galal¹, Hagar K Hassan², Nada F Atta², Timo Jacob³

Affiliations

¹ Department of Chemistry, Faculty of Science, University of Cairo, 12613 Giza, Egypt. Electronic address: galal@sci.cu.edu.eg.
² Department of Chemistry, Faculty of Science, University of Cairo, 12613 Giza, Egypt.
³ Institute of Electrochemistry, Ulm University, 89081 Ulm, Germany; Helmholtz-Institute-Ulm (HIU) [d], Helmholtzstr. 11, 89081 Ulm, Germany; Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany. Electronic address: timo.jacob@uni-ulm.de.

PMID: 30553090
DOI: 10.1016/j.jcis.2018.12.018

Abstract

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.

Keywords: Combustion method; Green synthesis; Microwave synthesis; Neutral electrolytes; Ru-based RGO; Supercapacitors.