After confirming the structure of COF@bio and its composites, their electrochemical performances were evaluated within a voltage range of 0.005-3.0 V (vs. Li⁺/Li) in CR2032 coin cells. Cyclic voltammetry (CV) with a scan rate of 0.1 mV s -1 was initially employed to investigate the electrochemical processes of the anodes. As depicted in Fig. , several reduction peaks of COF@bio-40 during the first scan were observed, attributed to the irreversible reduction formed by the solid electrochemical interphase (SEI). In subsequent cycles, the CV curves gradually overlapped, indicating that the electrode material exhibited excellent cyclic reversibility. The oxidation/reduction peak pairs at 0.17/0.007 V and 1.18/0.76 V may correspond to the reversible lithiation/delithiation behavior of the benzene rings and furane rings. The other peak pair at 2.51/1.54 V was due to the electrochemical interaction of Li⁺ with the imine linkage. All these results indicated a multistep Li doping process within the active structure of COF@bio-40.