Energy Accumulation Enabling Fast Synthesis of Intercalated Graphite and Operando Decoupling for Lithium Storage

Metal chloride‐intercalated graphite with multiple/versatile functions is one of the promising categories for charge storage, especially in achieving high volumetric and gravimetric performance simultaneously. Herein, a novel field‐induced energy accumulation strategy is proposed and demonstrated to achieve minute‐level fast preparation of stage‐1 dominated FeCl 3 ‐graphite intercalation compounds (GICs). The microwave‐induced Joule heat and electron excitation from the graphite conjugated system produce the arc plasmas with high energy density in the limited microenvironment, accompanied by the enhanced internal energy of gaseous reactant molecules and the strengthened intercalation reaction kinetics. When evaluating the anode for lithium storage, the FeCl 3 ‐graphite intercalation compounds feature the promoted self‐activation characteristics and deliver a high volumetric capacity up to 1650 mAh cm −3 . In particular, with the assistance of the operando Raman technique, it is interesting to find that the electronic decoupling effect among graphite and FeCl 3 layers is responsible for the self‐activation process. Thus, it is reasonable to believe that this work can further offer an insightful and referable idea into the in‐depth investigation of metal chloride intercalated graphite, especially for applications in lithium storage.