Fig. 7.

Structural variations and the density functional theory (DFT) calculation of COF in COF@CNTs anode. a XRD patterns of as-prepared COF@CNTs and the COF@CNTs anode after the first cycle and 500 cycles. b Reaction free energies (ΔG) at various stages of the lithiated COF monomer. Reaction free energies were determined by subtracting the minimized energies of the lithiated COF monomer at each lithiation stage from those of the initial compounds and lithium. c The structure evolution during the lithiation process. The binding sites between lithium and COF are highlighted with red, yellow, blue, orange, and purple colors, respectively