The role, formation and characterization of LiC₆ in composite lithium anodes

To solve the problems of large volume changes and the formation of lithium dendrites in lithium metal batteries, the incorporation of carbon into the lithium metal anodes has gained considerable attention due to its excellent chemical and electrochemical stability, as well as its exceptional mechanical strength that allows repeated cycling. This review provides a comprehensive overview of the formation of lithiated graphite (LiC₆) and its role in both bulk and electrode-electrolyte interface regions during lithium plating and stripping. In bulk form, LiC₆ has excellent lithiophilic properties, reducing the overpotential for lithium nucleation and promoting uniform lithium deposition. Additionally, when LiC₆ is introduced at the electrode-electrolyte interfaces, it improves contact between the electrode and electrolyte by acting as a buffering layer, thereby reducing interfacial impedance. Finally, prospects and challenges for the development of Li/C composite anodes are discussed.