Phthalonitrile Resin‐Derived Multi‐Element Doped Porous Carbon Materials for Supercapacitors

ABSTRACT

The design of electrode materials with hierarchical charge‐transfer structures and efficient ion/electron transport is essential for enhancing supercapacitor performance. In this study, two S‐containing phthalonitrile monomers were synthesized, and nitrogen‐ and sulfur‐co‐doped porous carbons were produced via urea/ZnCl ₂ ‐assisted in situ foaming‐curing followed by low‐loading KOH activation. The optimized material exhibited a high specific surface area of 2643 m ²  g ⁻¹ and a hierarchical microporous‐mesoporous structure, enabling efficient ion transport. Symmetric supercapacitors fabricated using the porous carbon based on 4,4′‐di(3,4‐dicyanophenoxy)diphenyl sulfone achieved a specific capacitance of 281 F g ⁻¹ at 0.1 A g ⁻¹ , maintained 96% capacitance retention after 10,000 cycles at 0.5 A g ⁻¹ , and delivered an energy density of 27.77 Wh kg ⁻¹ at a power density of 55.56 W kg ⁻¹ . Quantum chemical calculations further revealed that SO functional groups facilitated OH ⁻ adsorption and electrolyte/electrode interfacial interaction. This study presents a resin‐derived porous carbon design strategy that combines molecular precursor design, in situ foaming, and a low KOH/resin weight ratio to construct high‐surface‐area heteroatom‐doped carbon electrodes.