A topology‐guided design strategy for polymerized naphthoquinone cathodes in rechargeable aluminium‐ion batteries

Abstract

Rechargeable aluminium-ion batteries (RAIBs) are promising candidates for sustainable energy storage owing to their low cost, safety, and resource abundance. However, the lack of durable cathode materials restricts their development. Here, we propose a topology-guided design strategy by synthesizing three thioether-bridged naphthoquinone polymers from 1,4-naphthoquinone. Structural characterization combined with density functional theory calculations confirms that polymerization reduces crystallinity, enhances thermal stability, and extends π-conjugation, with the para-topology providing the most favorable configuration and strongest AlCl2+ coordination. The nearly planar para-naphthoquinone polymer (p-PNQ) exhibits an extended conjugated backbone, reduced bandgap, and uniform electrostatic potential distribution. Electrochemical tests reveal that p-PNQ delivers 146 mAh g−1 initially at 0.1 A g−1 and a 97.2% retention after 500 cycles, surpassing pristine 1,4-NQ and o-/m-isomers. Ex situ analyses confirm that redox activity originates from reversible coordination between carbonyl groups and AlCl2+ species. This study establishes molecular topology as a key parameter for designing organic cathodes, and demonstrates that topology-controlled strategies enable durable, high-performance cathodes for energy storage in RAIBs.