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

Authors: Sha Li, Jiande Lin, Huiqun Wang, Shiyuan Zhou, Xiangyang Guo, Xiao Zhan, Hongwei Tao, Haitao Hu, Zhengyou He, Honggang Liao, Dongping Zhan, Li Zhang*

Abstract: 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.

Full-Link: https://onlinelibrary.wiley.com/doi/10.1002/anie.202423186