Electronic Structure of Graphite Dictates Interfacial Stability in Propylene Carbonate Electrolytes Beyond SEI Formation

Abstract The long‐standing incompatibility between graphite anodes and propylene carbonate (PC)‐based electrolytes has been conventionally attributed to the failure to form a protective solid‐electrolyte interphase (SEI). Herein, it is demonstrated that the interfacial electrochemical behavior is fundamentally governed by the electronic structure of graphite, rather than the SEI itself. Through comparative studies of 3R/2H‐phase and 2H‐phase graphite, it is revealed that a pre‐formed SEI effectively suppresses Li + –PC co‐intercalation in 3R/2H graphite, while it fails in the 2H counterpart. With the addition of vinylene carbonate (VC), the 3R/2H graphite achieves a high initial Coulombic efficiency of 94.7%, far exceeding that of 2H graphite (60.8%). Although a uniform and fluorine‐rich SEI forms on the 3R/2H graphite, it is established that this SEI is a consequence—not the cause—of interfacial compatibility. Instead, the higher ionization energy and lower surface conductivity of 3R/2H graphite impede electron transfer to Li + –(PC) x complexes, thereby elevating the reduction overpotential and mitigating solvent decomposition. This work shifts the paradigm from SEI‐centric views to a holistic understanding of graphite–electrolyte interplay, offering new principles for designing compatible PC‐based electrolytes for low‐temperature and high‐voltage lithium‐ion batteries.