Fluorinated Composite Electrolyte for Stable Sulfide Battery Interfaces

A solid electrolyte interface (SEI) layer is formed at the interface between the liquid electrolyte and sulfide-based solid electrolyte. This SEI layer acts as an intermediary that prevents direct contact and chemical side reactions between the liquid electrolyte and solid electrolyte, while still allowing lithium ion transport. The SEI layer is created through preliminary reaction or coating processes, establishing a protective barrier that resolves the contradiction between maintaining ionic conductivity and preventing harmful chemical reactions.

The invention creates a composite electrolyte system combining liquid electrolyte and sulfide-based solid electrolyte in a controlled manner. The liquid electrolyte component provides high ionic conductivity, while the solid electrolyte component maintains flame retardancy and thermal stability. The composite structure allows the system to benefit from both materials' advantages, achieving high conductivity without sacrificing safety properties like flame retardancy.

The invention modifies the chemical composition and physical parameters of the liquid electrolyte to achieve compatibility with sulfide-based solid electrolyte. By adjusting parameters such as electrolyte concentration, additives, and molecular structure, the liquid electrolyte is optimized to prevent oxidation reactions at high voltages while maintaining high ionic conductivity. This parameter optimization allows the composite electrolyte to operate stably at high voltages without deterioration.