Rational Design of Naphthol Groups Functionalized Bipolar Polymer Cathodes for High Performance Alkali‐Ion Batteries

Abstract Redox‐active organic compounds gather significant attention for their potential application as electrodes in alkali ion batteries, owing to the structural versatility, environmental friendliness, and cost‐effectiveness. However, their practical applications of such compounds are impeded by insufficient active sites with limited capacity, dissolution in electrolytes, and sluggish kinetics. To address these issues, a naphthol group‐containing triarylamine polymer, namely poly[6,6′‐(phenylazanediyl)bis(naphthol)] (poly(DNap‐OH)) is rationally designed and synthesized, via oxidative coupling polymerization. It is capable of endowing favorable steric structures that facilitate fast ion diffusion, excellent chemical stability in organic electrolytes, and additional redox‐active sites that enable a bipolar redox reaction. By exploiting these advantages, poly(DNap‐OH) cathodes demonstrate remarkable cycling stability in both lithium‐ion batteries (LIBs) and potassium‐ion batteries (PIBs), showcasing enhanced specific capacity and redox reaction kinetics in comparison to the conventional poly(4‐methyltriphenylamine) cathodes. Overall, this work offers insights into molecular design strategies for the development of high‐performance organic cathodes in alkali‐ion batteries.