Structural, magnetic, electrical, and electrochemical properties of Sr–Co–Ru–O: A hybrid-capacitor application

In this study, we report the synthesis of SrCo_1−xRu_xO_3−δ nominal compositions, where x = 0.0-1.0, using solid-state reaction technique. XRD analysis confirms the structure of x = 0 sample as hexagonal Sr₆Co₅O₁₅. As the Co ions are substituted by Ru, a two-phase structure (hexagonal R32 and orthorhombic Pbnm) emerges up to x ≤ 0.5. As the Ru content is increased further, the hexagonal R32 phase disappears completely and an orthorhombic Pbnm phase becomes the main phase. SEM images show that grain size of the samples decreases with increasing Ru content. Temperature-dependent electrical conductivity studies indicate upon Ru substitution in the nominal SrCo_1−xRu_xO_3−δ compounds, resistivity decreases due to appearance of metallic SrRuO₃ phase. The cyclic voltammogram (CV) of the samples show capacitive properties upon Ru substitution. The cycle measurements of the capacitors yield promising results for potential supercapacitor applications.