Electrochemical and structural insights into ionic cerium-doped polyaniline nanofibers for energy storage

Official URL: https://dx.doi.org/10.1016/j.electacta.2025.147667

This study presents a novel approach for enhancing polyaniline (PANI)-based supercapacitor electrodes by directly incorporating ionic Ce3+ ions via in situ polymerization—a strategy that circu mV ents the limitations of conventional CeO₂-based composites. A series of composites with varying Ce content (5–50 %) were evaluated using structural, morphological, and electrochemical characterizations. PANI:Ce10 exhibited the highest specific capacitance (425.8 F g⁻¹ ) and energy density (21.3 Wh/kg) in a two-electrode configuration. These results outperformed both undoped and over-doped counterparts, highlighting the importance of optimal ionic doping. Mechanistic insights from BET and EPR analyses reveal that ionic Ce doping induces enhanced surface mesoporosity and elevated polaron density, thereby facilitating faster ion diffusion and higher pseudocapacitive contribution. This compositional optimization demonstrates that Ce³⁺ concentration critically governs electron delocalization and redox reversibility. The composite also demonstrated outstanding cyclic stability with 95.5 % retention over 10,000 cycles. The two-electrode configuration enables realistic evaluation of supercapacitor performance. Overall, this work provides an experimentally grounded pathway to engineer redox-active polymer nanostructures via rare-earth ionic doping, offering a scalable and high-performance solution for advanced electrochemical energy storage.