A High-Performance Li-B-H Electrolyte for All-Solid-State Li Batteries

Highly Li-ion conductive Li-4(BH4)(3)I@SBA-15 is synthesized by confining the LiI doped LiBH4 into mesoporous silica SBA-15. Uniform nanoconfinement of P6(3)mc phase Li-4(BH4)(3)I in SBA-15 mesopores leads to a significantly enhanced conductivity of 2.5 x 10(-4) S cm(-1) with a Li-ion transference number of 0.97 at 35 degrees C. The super Li-ion mobility in the interface layer with a thickness of 1.2 nm between Li-4(BH4)(3)I and SBA-15 is believed to be responsible for the fast Li-ion conduction in Li-4(BH4)(3)I@SBA-15. Additionally, Li-4(BH4)(3)I@SBA-15 also exhibits a wide apparent electrochemical stability window (0 to 5 V vs Li/Li+) and a superior Li dendrite suppression capability (critical current density 2.6 mA cm(-2) at 55 degrees C) due to the formation of stable interphases. More importantly, Li-4(BH4)(3)I@SBA-15-based Li batteries using either high-capacity sulfur cathode or high-voltage oxide cathode show excellent electrochemical performances, making Li-4(BH4)(3)I@SBA-15 a very attractive electrolyte for next-generation all-solid-state Li batteries.