Formation Energy‐Dominated AB‐Stacking Structure Promotes Metal‐Covalent Organic Frameworks for High‐Performance Dual‐Ion Storage Potassium‐Ion Batteries

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Abstract
The long‐range AA‐stacking structures present in most covalent organic frameworks (COFs) result in poor utilization of redox‐active sites and suboptimal electrochemical performance. Herein, we report a metallized COF (Cu@MCOF‐D) by pre‐synthesizing cyclic trinuclear copper clusters (Cu 3 ) and integrating them with 2,6‐diaminoanthraquinone (DAAQ). Formation energy calculations confirm that the material possesses a thermodynamically stable AB‐stacking structure, which effectively alleviates interlayer K + adsorption shielding and optimizes the interlayer K + diffusion kinetics. Results from ex situ transmission electron microscopy analyses under different charge/discharge states indicate that Cu 3 exhibits strong adsorption capability toward FSI − , while the ‒C═O/‒C═N‒ groups chemically bind K + , and together they synergistically enable dual‐ion storage. When applied as potassium‐ion battery (PIB) anode, the reduced diffusion barrier allows a high reversible capacity of 153.8 mAh g −1 at 20.0 A g −1 , and delivers 96.8% capacity retention after 6500 cycles at 5.0 A g −1 , demonstrating exceptional long‐term K + storage stability. In PIB full cells using potassium iron hexacyanoferrate as the cathode, a high energy density of up to 197.5 Wh kg −1 is achieved. Furthermore, by employing 3,4,9,10‐perylenetetracarboxylic dianhydride heat‐treated at 450°C as the cathode, outstanding cycling stability is realized, with a capacity retention of 93.2% after 2000 cycles.
Funding Information
  • National Natural Science Foundation of China (22479078)
  • National Natural Science Foundation of China (22179063)

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