In Situ Electrochemical\nPolymerized Bipolar-Type Poly(1,5-diaminonaphthalene)\nCathode for High-Performance Aqueous Zinc-Organic Batteries

Electroactive organic materials, characterized by their\nflexible\nmolecular architecture and rapid reaction kinetics, demonstrate an\nenormous potential for applications in aqueous zinc-ion batteries\n(AZIBs). However, small-molecule organic electrode materials often\nencounter dissolution-induced capacity decay, whereas polymeric counterparts,\ndespite their limited solubility in electrolytes, confront poor conductivity\nissues. To tackle these challenges, optimizing molecular structures\nand synthesis routes is paramount. In this study, we have elaborately\ndesigned an electrochemical polymerized poly(1,5-diaminonaphthalene),\ntermed PDAN-1, as a high-performance cathode material for AZIBs. Compared\nto the chemically polymerized counterpart, termed PDAN-2, PDAN-1 exhibits\nsignificantly enhanced electrochemical performance, owing to its markedly\nreduced electrochemical resistance. Specifically, the PDAN-1 cathode\nachieves a high discharge capacity of 243 mAh g<sup>–1</sup> at a current density of 0.1 A g<sup>–1</sup>. Additionally,\nit exhibited long-term cycle stability, retaining over 85% of its\ncapacity even after 2700 cycles at 2 A g<sup>–1</sup>. Impressively,\neven under a substantial mass loading of 10 mg cm<sup>–2</sup>, PDAN-1 maintains a discharge capacity of 170 mAh g<sup>–1</sup>, underscoring its vast potential for practical applications in AZIBs.\nFurthermore, ex situ analyses and density functional theory calculations\ncollectively reveal that the PDAN-1 cathode operates through a bipolar-type\ncharge storage mechanism, providing insights into its unique electrochemical\nbehavior and further validating its suitability for AZIB applications.