In addition, the bandgap of COF@bio was analyzed (Fig. ), demonstrating its semiconductor properties and limited electronic conductivity. Therefore, doping with highly conductive materials, such as CNT, is necessary to improve electronic conductivity. DFT calculations were then conducted to evaluate the binding energy and adsorption energies of lithium atoms during various stages of the lithiation process within COF@bio. From Fig. and Fig. , the total energy of the pristine COF@bio was -7.99 × 10³ eV. After lithiation of the imine bond, the total energy of COF@bio-6Li decreased to -9.21 × 10³ eV, with a minimum binding energy (BE1) of -20.90 eV. Meanwhile, the adsorption energy per lithium atom at site 1 was lower than at other sites (Fig. ), indicating that the imine bonds preferentially adsorb lithium. Subsequently, the benzene ring, which exhibited a negative ESP, absorbed a Li atom, resulting in a total energy of -9.62 × 10³ eV for COF@bio-8Li. This lithiation step had a BE2 of -6.37 eV, and the adsorption energy per lithium atom at site 2 was -2.31 eV. Finally, COF@bio-11Li achieved a total energy of -1.02 × 10⁴ eV, with the binding energy, BE3, of -6.09 eV. This process also showed an adsorption energy per lithium atom of -2.03 eV. These results illustrated that, in theory, the imine bonds, benzene rings, and furan rings within COF@bio can store lithium ions. Based on the capacity contribution, XPS, and DFT analyses, it was suggested that the benzene rings, imine linkages, and furan rings were involved in the lithium storage process, indicating an 11-lithium storage capacity for a single COF monomer. The proposed redox mechanism of COF@bio in the composite is illustrated in Fig. . b) Band structure of the COF@bio. c) The lithiation pathway of COF@bio and the reaction free energies (ΔG) at various stages of the lithiated COF@bio. d) The adsorption energy per Li + ion at different sites of COF@bio. e) Schematic gradual lithiation and delithiation of COF@bio in the complex during the discharge and charge cycles.