Fig. 1: Structure and characterizations of TQBQ-COF materials.

a The chemical structure and possible electrochemical redox mechanism of TQBQ-COF with a theoretical capacity of 515 mAh g−1. b Top and side views of the schematic AB stacking model of TQBQ-COF layers with a packing distance of 3.07 Å. c PXRD pattern and the simulated AB/AB' stacking models of TQBQ-COF powder. d High-resolution TEM image of TQBQ-COF with a multilayer stacking space of ~0.30 nm. Scale bar, 5 nm. e SAED pattern of (002), (201), and (600) facets of TQBQ-COF from d. Scale bar, 5 nm−1.