Macromolecular Design of Bipolar Donor–Acceptor Polymer Cathodes for Fast and Durable Aluminum Dual‐Ion Batteries

Abstract

Rechargeable aluminum dual‐ion batteries (ADIBs) are promising for sustainable electrochemical energy storage, yet organic cathodes rarely combine efficient bipolar redox utilization, rapid charge transport, long‐term durability, and operation at high mass loadings. Here, four phenothiazine–anthraquinone donor–acceptor polymers are constructed by varying chain architecture, D–A connectivity, and backbone rigidity to elucidate how macromolecular structure regulates bipolar charge storage. The resulting structure–transport relationships reveal that open crosslinked networks improve ion accessibility, whereas direct D–A conjugation within rigid backbones promotes orbital delocalization and charge transfer. These complementary structural features activate both p‐type phenothiazine and n‐type anthraquinone redox centers, enabling reversible co‐storage of AlCl 4 − and AlCl 2+ . Accordingly, the optimized PTZAQ‐C3 delivers a reversible capacity of 243 mAh g −1 , excellent rate capability (122 mAh g −1 at 50.0 A g −1 ), and exceptional cycling stability up to 90,000 cycles. PTZAQ‐C3 also maintains 200 mAh g −1 at −30°C and reaches an areal capacity of 10.08 mAh cm −2 at a mass loading of 50.4 mg cm −2 . These findings highlight macromolecular design as a general strategy for developing high‐performance bipolar organic cathodes for aluminum dual‐ion and related multicarrier batteries.