Camphor sulfonic acid assisted synthesis of polythiophene composite for high energy density all-solid-state symmetric supercapacitor

Here, we report a high energy density all-solid-state symmetric supercapacitor (SSC) based on polythiophene/Al₂O₃ (PTCA) composite synthesized via camphor sulfonic acid assisted chemical polymerization of thiophene. An electrochemical study showed that polythiophene/50%Al₂O₃ (PTCA5) composite electrode exhibits the highest gravimetric specific capacitance of 780.40 Fg⁻¹ at 0.5 Ag⁻¹ in three electrode system. Subsequently, the all-solid-state symmetric supercapacitor (SSC) fabricated using PTCA5 electrode achieved a specific capacitance of 472.8 Fg⁻¹ at 1 Ag⁻¹ using PVA-KOH gel as an electrolyte. Moreover, SSC showed excellent cyclic performance with 90.54% capacitance retention of its initial capacitance even after 5000 cycles. Additionally, a superior specific energy density of 58.04 Whkg⁻¹ was obtained at a specific power density of 533.02 Wkg⁻¹ for the same. This high potential and high energy density device find its application in the low-cost energy storage devices. Encouragingly, the fabricated SSC is utilized to light a commercial red LED effectively to validate the real usage.