Polyaniline wrapped graphene quantum dot decorated strontium titanate for robust high-performance flexible symmetric supercapacitors

Abstract

Design and development of promising electrode materials for supercapacitors has been a vital topic of current research focus. Here, we report the supercapacitive performance of the strontium titanate–graphene quantum dot–polyaniline heterohybrid. The synthesis strategy involves a sequential sol–gel synthesis of strontium titanate, followed by hydrothermal aided interface formation with graphene quantum dots (GQD) and polyaniline (PANI) deposition by chemical oxidative polymerization. A high specific capacitance of 2134 F g⁻¹ could be observed in 1 M H₂SO₄ electrolyte at a current density of 1 A g⁻¹. The Ragone plot for the symmetric cell reveals an energy density of 16.2 W h kg⁻¹ at a power density of 4533.7 W kg⁻¹. The 97.7% retention of specific capacitance demonstrated at higher current densities ensures high rate capability. Further, the device demonstrated a capacitance retention of 80% at 10 A g⁻¹ after 10000 galvanostatic charge–discharge cycles. Low interfacial charge transfer resistance as evidenced by impedance spectroscopy analysis and high performance could be attributed to the synergistic interaction at the interface.