Boosting the Li|LAGP interfacial compatibility with trace nonflammable all‐fluorinated electrolyte: The role of solid electrolyte interphase

Abstract NASCION‐type lithium (Li) conductors provide a great chance to break the challenges of solid‐state lithium batteries (SSLBs) emphasizing superior safety and high energy density. Nonetheless, their practical employment has been hampered by the poor interfacial compatibility. Herein, we successfully block interfacial side reactions by in situ constructing a LiF‐enrich solid electrolyte interphase (SEI) layer between Li metal and LAGP (Li_1.5Al_0.5Ge_1.5(PO₄)₃) through dropping trace fluoroacetonitrile‐based all‐fluorinated electrolyte. Noted that the formed high Young's modulus but fast‐kinetics LiF‐rich SEI layer successfully suppresses growth of Li dendrite, further tailoring the superior interfacial chemistry. Consequently, such robust SEI upgrades critical current density of LAGP to a record‐high value of >1.5 mA cm⁻². Furthermore, a hybride full cells assembled with the commercial‐level cathode deliver prominently cycling lifespan (>250 cycles) and outstanding rate performance. The present SEI engineering strategy enables a huge leap toward the industrialized deployments of SSLBs. image