摘要
Covalent organic frameworks(COFs)have garnered increasing attention as promising electrode materials for sodium-ion batteries(SIBs)due to their ordered backbones,uniform pore sizes,and high surface areas.However,they also face challenges,including low capacity,unsatisfactory rate performance,and limited cycling stability,which pose the primary obstacles to their practical use.Herein,a pyrenoimidazole-based COF,denoted as PyIm-COF,has been synthesized as a novel electrode material for highperformance SIBs using an efficient synthetic strategy.With extended fully conjugated backbones and readily accessible redox-active sites,PyIm-COF demonstrates remarkable high-rate performance,delivering around 250 m Ah g^(−1)and excellent cycling stability,retaining 97.2%of its capacity even after 2500 cycles at 5 A g^(−1),which is higher than that of most previously reported COF-based SIBs.This work provides valuable insights into the development of nitrogen-rich conjugated COF electrode materials for rechargeable SIBs.
基金
the Natural Science Foundation of Liaoning province(grant no.2019-MS-046)
W.Zhang thanks the University of Colorado Boulder for financial support of this work
W.Huang acknowledges the support from the National Natural Science Foundation of China(grant no.21875206)
The authors acknowledge the assistance of the Dalian University of Technology Instrumental Analysis Center.
