Anion Co‐Intercalation in Conductive 2D MOFs via π‐d Hybridization for High‐Performance Magnesium Batteries

ABSTRACT Rechargeable magnesium batteries (RMBs) are a promising post‐lithium battery technology due to abundant magnesium reserves, high volumetric capacity, and dendrite‐free Mg anodes. However, the strong electrostatic interaction between Mg 2+ and inorganic cathode lattices causes high diffusion barriers and sluggish kinetics. To circumvent this, two‐dimensional conductive metal‐organic frameworks (2D c‐MOFs), featuring favorable electronic transport characteristics arising from π‐d hybridization and structural tunability, have attracted widespread attention. This work systematically investigates the electrochemical performance of M 3 (HITP) 2 (M = Co, Ni, Cu; HITP = 2,3,6,7,10,11‐hexaiminotriphenylene) as cathodes for RMBs and reveals the decisive role of the metal center in Mg storage. All three materials achieve synergistic dual‐ion storage through heteroatomic N coordination with Mg 2+ coupled with anion intercalation. Among them, Ni 3 (HITP) 2 demonstrates superior overall performance, arising from its characteristic Ni 2+ d 8 electronic configuration, which facilitates the formation of a stable Ni‐N coordination environment and effective π‐d conjugation. It retains approximately 201 mAh g −1 after 1100 cycles at 1.0 A g −1 , corresponding to a high‐capacity retention of 98.0%. This study elucidates how different metal centers regulate Mg storage in 2D c‐MOFs, providing molecular‐level guidance for designing high‐performance organic cathodes for multivalent‐ion batteries.