Intercalation‐Enabled Charge Storage in Tertiary Nanocomposites of Polypyrrole, Sulphonated Carbon Quantum Dots, and Y ₂ O ₃ for Advanced Asymmetric Supercapacitors

ABSTRACT This research involved the synthesis and systematic evaluation of a series of ternary nanocomposites made from polypyrrole (PPY), sulphonated carbon quantum dots (CQDs), and yttrium oxide (Y 2 O 3 ) as advanced electrode materials for high‐performance supercapacitors. The combination of CQDs and Y 2 O 3 within the conductive PPY matrix resulted in a synergistic enhancement of electrochemical properties, featuring excellent electrical conductivity, numerous redox‐active sites, and superior structural stability. Among all formulations, the 0.4 PCY(PPY, sulphonated CQDs, and Y 2 O 3 ) composite demonstrated the highest specific capacitance of 894.3 F/g at a rate of 2 mV/s, surpassing pure PPY (493.3 F/g), CQDs (128.2 F/g), and Y 2 O 3 (398.2 F/g). This significant enhancement is attributed to the optimized charge transfer pathways facilitated by CQDs and the strong pseudocapacitive effect of Y 2 O 3 , which promote efficient ion diffusion and electron transport. Galvanostatic charge–discharge tests further validated the exceptional performance of 0.4 PCY, which achieved a specific capacitance of 860.16 F/g at 1 A/g, maintaining 42% (361.79 F/g) even at 5 A/g. The electrode reached an impressive energy density of 119.4 Wh/kg and a corresponding power density of 2022.5 W/kg, exhibiting remarkable cycling stability with 98.1% capacitance retention after 10 000 cycles. These findings illustrate the high reversibility and durability of the composite. An asymmetric supercapacitor (ASC) device constructed with 0.4 PCY as the positive electrode successfully powered a 1 V Light‐emitting diode (LED) for 4.43 min following a 10‐min charge at 3 V, demonstrating its practical applicability. In summary, the study emphasizes the 0.4 PCY nanocomposite as a promising and efficient electrode material for future flexible and high‐energy‐density supercapacitor systems.