Strengthening the Interface between Flower‐Like VS4 and Porous Carbon for Improving Its Lithium Storage Performance

Carbon materials are frequently used to improve the cycle and rate performance of VS₄ as anode material for lithium ion batteries. However, the interfacial interaction between VS₄ and carbon has not been elucidated clearly. Various VS₄@C composites are prepared and the interface between VS₄ and porous carbon is investigated by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and first‐principles calculations. The interfacial structure between VS₄ and carbon and the mechanism of flower‐like VS₄ growth on carbon substrate are revealed clearly. The results indicate that C?V bonds and C?O?V bonds are formed when oxygen functional groups are introduced into the porous carbon, and the C?V bonds and C?O?V bonds accelerate the electron transport and enhance structural stability of the VS₄@C composite. Deriving from the unique structure and robust interfacial interaction, the electrochemical performances of VS₄@C composite are much better than that of pure VS₄. Moreover, through the study of lithium storage mechanism of VS₄ anode, it is found that there is an irreversible amorphization change of the original VS₄ in the first cycle, and that during the following electrochemical process, the main storage behavior of lithium ions derives from the insertion?extraction reactions in the amorphous VS₄ with the reaction between V⁴⁺ and V³⁺.