High energy density pseudocapacitor based on a nanoporous tungsten(VI) oxide iodide/poly(2-amino-1-mercaptobenzene) composite

Abstract The synthesis of the tungsten( VI ) oxide iodide/poly-2-amino-1-mercaptobenzene nanoporous composite (W(VI)OI/P2AMB-NP composite) follows a two-step process. Initially, 2-amino-1-mercaptobenzene undergoes oxidative polymerization using iodine as the oxidant, followed by a double replacement reaction with Na 2 WO 6 . This process leads to the formation of a unique composite structure, where nanoparticles ranging from 15 to 20 nm aggregate into larger secondary particles exceeding 500 nm and further assemble into micrometer-scale clusters (>1 µm). X-ray diffraction analysis confirms the high crystallinity and semiconducting nature of the composite, revealing a remarkably small crystalline size of ∼59 nm. This well-defined nanostructure contributes significantly to its charge storage performance. Electrochemical characterization was carried out using a three-electrode system, where the W(VI)OI/P2AMB-NP composite exhibited a high specific capacitance ( C s ) of 200 F·g −1 at a current density of 1.0 A·g −1 . Additionally, the material demonstrated an impressive energy density of 49.9 Wh·kg −1 , indicating its strong potential as an advanced pseudocapacitor electrode. Beyond its electrochemical efficiency, this composite is cost-effectiveness and amenable to scalable synthesis, supporting its suitability for commercial applications. Long-term cycling stability tests revealed excellent durability, with 99.1% capacitance retention after 1,000 charge–discharge cycles. These attributes position the W(VI)OI/P2AMB-NP composite as a highly promising candidate for next-generation energy storage systems, offering a compelling combination of performance, stability, and economic viability.