Enhancing the lithium compatibility of superior ionic conducting LGPS solid electrolyte via silane-coupling agent modification

Sulfide solid electrolytes have garnered increasing attention due to their remarkable ionic conductivity and facile cold-pressing fabrication process. However, their poor chemical and electrochemical compatibility with lithium metal anodes severely limits their practical application in lithium metal batteries. In this work, we propose an innovative strategy to improve the interfacial compatibility of Li 10 GeP 2 S 12 (LGPS) solid electrolytes with lithium metal anodes by grafting a thin silane-coupling agent (SiA) layer onto LGPS particles. This SiA layer functions as the artificial solid electrolyte interphase, preventing direct physical contact with lithium metal, and thus preventing undesirable interfacial reactions. On the other hand, the formed Si–S bonds between SiA and LGPS prevents the decomposition and reduction of (Ge, P) S₄ tetrahedra by lithium metal. Benefiting from the enhanced interfacial stability, our high-performance SiA-LGPS electrolyte exhibits a comparable ionic conductivity of 1.12 mS cm −1 , a critical current density of 2.2 mA cm −2 at room temperature, and stable cycling performance for over 600 h at a current density of 0.1 mA cm −2 . Furthermore, LiNi 0.8 Mn 0.1 Co 0.1 O 2 /SiA-LGPS/Li cells achieve stable discharge capacities and desirable cycling stability at room temperature. Our approach provides an innovative solution for the practical application of sulfide solid electrolytes in high-energy-density lithium-metal batteries.