Molecularly chemical prelithiation of soft carbon towards high-performance lithium-ion capacitors

The crucial role of prelithiation in lithium-ion capacitor arises from the lithium-deficiency hurdle intrinsic to cathode. Although a multitude of efforts have been dedicated to investigating electrochemical compensation of lithium ions, the homogeneity and safety hazards limit the development of prelithiation. Herein, a molecularly chemical prelithiation of amorphous soft carbon is reported for the first time. Using 2-methyltetrahydrofuran (MTHF) as prelithiation solvent and a suitable prelithiation time of 5 min, prelithiated soft carbon (SC-5-MTHF) has a low potential of 0.21 V vs. Li/Li+. The structure of SC-5-MTHF is chemically stable, and the preformed solid electrolyte interface layer on the surface of soft carbon can ensure a high reversibility of lithium-ion during charge-discharge process. Lithium-ion capacitor constructed with SC-5-MTHF as anode and activated carbon as cathode exihibits a high capacitance retention of 96.7 % after 5000 cycles.