Three‐Dimensional Metal‐Organic Frameworks with Selectively Activated Aromatic Rings for High‐Capacity and High‐Rate Lithium‐Ion Storage

Metal‐organic frameworks (MOFs) are considered promising candidates for anode materials in Li‐ion batteries (LIBs) owing to their designable structure, abundant active sites, and well‐organized porosity. However, the structural factors governing active site utilization and Li‐ion storage kinetics remain inadequately understood. In particular, the Li‐ion storage behaviors of aromatic rings with high LUMO energy levels and situated in varying chemical environments remain a highly debated issue. Herein, a new cobalt‐based MOF (Co‐NTTA, NTTA ligand: 5,5′,5″‐((4,4′,4″‐nitrilotris(benzoyl))tris‐(azanediyl))triisophthalic acid), featuring aromatic rings situated in diverse local environments, is deliberately designed and synthesized. Experimental characterizations and first‐principles calculations have verified the occurrence of a reversible electrochemical reaction involving a total of 51 electrons among the NTTA ligands, cobalt cations, and Li+ ions. Unlike the traditional concept of superlithiation, the three inner aromatic rings are selectively activated by π‐aromatic conjugation networks and π···π stacking, contributing to a reversible 6‐electron pseudocapacitive Li+ intercalation reaction. Conversely, the three outer aromatic rings remain inert toward Li+ ions. Impressively, the Co‐NTTA MOF anode, with selectively activated aromatic rings, delivers a reversible capacity of up to 956 mAh g−1 at 200 mA g−1 and demonstrates exceptional high‐rate durability, further supporting a 4.3 V lithium‐ion hybrid electrochemical capacitor with high energy/power density.