Microrod engraved bimetallic cobalt iron phosphate: electrode to liquid configured symmetric supercapacitive device

Abstract

Present report explores microrod-shaped bimetallic cobalt iron phosphate grown through a cost-effective, single-run chemical route at 70 °C on stainless steel substrate. XRD, FTIR, TEM, and XPS analyses confirm the formation of the Co₃Fe₄(PO₄)₆ phase, wherein cobalt exhibits a +2 oxidation state, and iron adopts a +3 oxidation state. SEM analysis reveals the interlocking arrangement of micro-rods. Obtained surface architecture enhances structural integrity and establishes an efficient electrical channel for electron transfer which excels exceptional specific capacitance to 1643 F/g at a 5 mV/s scan rate (1208 F/g at 2.5 mA/cm²) with an impressive stability of 98% at 5000 CV cycles. These excellent outcomes spurred the fabrication of a symmetric supercapacitor, exhibiting 170 F/g specific capacitance at 5 mV/s with a 1.3 V potential window. In-depth analysis has been conducted to identify the origin of capacitive behavior, examining both surface and diffusion-controlled charge components. Through a practical demonstration, the constructed device effectively operated a 1 V DC fan, showcasing its promising practical applications.