Lithium intercalated graphite with preformed passivation layer as superior anode for Lithium ion batteries

Graphite has been the most common anode materials in the Li-ion batteries (LIBs). However, it has a limited Coulombic efficiency and cycling stability which are crucial for the practical use of LIBs. Here, we present a lithium (Li)-intercalated graphite (LIG) electrode with a stable passivating layer on the surface for an improved electrochemical performance. The LIG was prepared by thermal treatment of commercial graphite in the presence of Li metal vapor and subsequent exposure to air. Characterization revealed that the surface of LIG was passivated by a thin inorganic compound (Li2CO3). This passivation layer on the graphite surface function as a preformed stable solid electrolyte interphase (SEI) films and allows the graphite electrode to deliver a high reversible capacity, high Coulombic efficiency, and stable cycle life.