Structure–Performance Relationships in Anthraquinone‐Disulfonate Coordination Polymers for Li‐Ion and Na‐Ion Battery Cathodes

Coordination polymers (CPs) based on organic redox‐active moieties offer a promising route to sustainable electrode materials for next‐generation batteries. Herein, the synthesis, crystal structure determination, theoretical characterization, and electrochemical evaluation of a series of anthraquinone‐disulfonate (AQDS) CPs incorporating Na ⁺ , Mg ²⁺ , and Cu ²⁺ ions ( AQDS‐Na , AQDS‐Mg , AQDS‐Cu ) as cathode materials for lithium‐ion and sodium‐ion storage are reported. Single‐crystal X‐ray diffraction reveals that AQDS‐Na adopts a 3D framework, while AQDS‐Mg and AQDS‐Cu form 2D layered structures with coordinated water molecules. These structural differences significantly influence the electrochemical performance. For Li‐ion storage, AQDS‐Na delivers an initial capacity of 120 mAh g ⁻¹ , while AQDS‐Mg and AQDS‐Cu show lower initial capacities (95 mAh g ⁻¹ and 106 mAh g ⁻¹ , respectively) and faster fading. For Na‐ion storage, the performance divergence is even more pronounced: AQDS‐Na achieves a stable capacity of 91 mAh g ⁻¹ after 100 cycles, while AQDS‐Mg and AQDS‐Cu suffer from significant capacity loss (47 and 18 mAh g ⁻¹ after 100 cycles, respectively), attributed to the presence of coordinated water molecules in the 2D frameworks. This study highlights the importance of structural dimensionality and coordination environment in designing high‐performance cathode materials for battery systems.