Origin of Superior Li-Ion Transport in Lamellar Lyotropic Liquid Crystals for Beyond-Liquid Electrolytes

Rational design of satisfactory electrolytes is of critical importance for efficient and sustainable energy devices. Herein, lamellar-nanostructured lyotropic liquid crystal (LLC) electrolytes showing beyond-liquid performance are designed for lithium-ion batteries (LIBs) by constructing desirable amphiphile/liquid interfaces for lithium ion (Li⁺) desolvation and transport. The lamellar LLC electrolytes are simply prepared by self-assembly of amphiphilic 1-hexadecyl-3-methylimidazoliumtetrafluoroborate ([C₁₆Mim][BF₄]) in conventional LiBF₄ liquid electrolytes, which forms periodic [C₁₆Mim][BF₄] nanolayers and liquid nanolayers. The interactions at the lamellar [C₁₆Mim][BF₄]/liquid interfaces facilitate Li⁺ desolvation for much higher transference numbers, and the lamellar interfaces provides ordered pathways for efficient transport of desolvated Li⁺. The Li⁺ transport along lamellar [C₁₆Mim][BF₄]/liquid interfaces in LLC electrolytes contributes 46% Li⁺ conductivities, which enables Li⁺ conductivities superior to those of liquid electrolytes. However, similar Li⁺ transport is lost at 1-hexadecyl-3-vinylimidazoliumtetrafluoroborate based lamellar LLC electrolytes because the high steric hindrance of rigid vinyl moieties. Original from Li⁺ transport along lamellar [C₁₆Mim][BF₄]/liquid interfaces, the LLC electrolytes show beyond-liquid performance in both efficiency and stability for LIBs. The work here provides fundamental guidance in the rational design of versatile nanostructured electrolytes with beyond-liquid performance for diverse energy devices.