Composition-Optimized Mesoporous SrTiO3/rGO Composite Electrodes for High-Performance Asymmetric Supercapacitors

Abstract

Composite electrodes substantially enhance supercapacitor performance through the synergistic effect of their constituent materials. In this study, strontium titanate (STO) nanoparticles were anchored onto and within the layers of reduced graphene oxide (rGO) to develop high-performance STO/rGO composite electrodes. A series of composites with varying weight ratios was synthesized to determine the optimal configuration for supercapacitor applications. Brunauer−Emmett−Teller (BET) analysis, Fourier-transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), and X-ray diffraction (XRD) were used to thoroughly analyze surface, morphological, and structural features. A three-electrode configuration was utilised to evaluate electrochemical performance parameters. In a 1 M NaOH electrolyte, the STO/rGO (1:2) composite demonstrated the maximum specific capacitance of 1133 F g−1 at 5 mV s−1. It also demonstrated outstanding cycling stability, holding onto 73.3% of its initial capacitance after 10,000 galvanostatic charge−discharge (GCD) cycles. STO/rGO (1:1) also demonstrated the maximum specific capacitance of 270 F g−1 at a current density of 9 A g−1. To demonstrate practical applicability, an asymmetric prismatic lab-scale supercapacitor device (STO/rGO || NaOH || ACb) was fabricated, and three devices connected in series successfully powered three LEDs (red, yellow, and green). These results highlight the strong potential of STO/rGO composites for advanced energy-storage technologies.