Synthesis of polyindole/gallium–gadolinium–aluminum garnet nano-composite for supercapacitor electrode

Supercapacitors are highly efficient energy storage devices that are known for their stability, ability to charge and discharge rapidly, extended cycle life, and impressive power density. However, their low energy density makes them unsuitable for energy-demanding applications like electric vehicles, requiring larger packs. This challenge has led to ongoing research focused on creating lightweight and cost-effective supercapacitors that can deliver optimal performance. This study aimed to develop a polyindole/gadolinium-gallium-aluminum garnet (PIn/GGAG) nano-composite tailored specifically for supercapacitor applications. The two-step synthesis process involved the sol-gel method to produce GGAG nano-powder, followed by creating the PIn/GGAG binary composite through a straightforward oxidative polymerization reaction. Scanning electron microscopy (SEM) was used to analyze the morphology of the composite, which was found to be within the 230–560 nm range. Characterization techniques, including XRD, FTIR, Raman, and FE-SEM, confirmed the presence of the GGAG phase. Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and impedance spectroscopy (EIS) were employed to scrutinize the supercapacitive performance in a three-electrode configuration. CV confirmed the contribution of the pseudo-capacitance mechanism at the interface of the PIn/GGAG nano-composite-coated carbon fiber (CF) and H 2 SO 4 electrolyte. The calculated specific capacitance (SC) using the CV technique was 105 F/g at a scan rate of 5 mV/s. The PIn/GGAG nano-composite-coated CF electrode demonstrated a charging potential increase of up to 1.8 V within 100s, coupled with a discharge time of approximately 90s. These findings suggest that the PIn/GGAG nano-composite has significant potential as a novel, high-performance lightweight supercapacitor electrode, potentially enhancing the longevity and charging efficiency in the hybrid energy systems of electric vehicles.