Interface Modification and Halide Substitution To Achieve High Ionic Conductivity in LiBH4-Based Electrolytes for all-Solid-State Batteries

A fast solid-state Li-ion conductor Li-16(BH4)(13)I-3@g-C3N4 was synthesized using a simple ball-milling process. Because of the combined effect of halide substitution and the formation of an interface between Li-16(BH4)(13)I-3 and g-C3N4, Li-16(BH4)(13)I-3@g-C3N4 delivers a high ionic conductivity of 3.15 X 10(-4) S/cm at 30 degrees C, which is about 1-2 orders of / magnitude higher than that of Li-16(BH4)(13)I-3. Additionally, Li-16(BH4)(13)I-3@g-C3N4 exhibits good electrochemical stability at a wide potential window of 0-5.0 V (vs Li/Li+) and excellent thermal stability. The Li/Li symmetrical cell based on the Li-16(BH4)(13)I-3@g-C3N4 electrolyte achieves long-term cycling with a small increase in overpotential, confirming superior electrochemical stability against Li foil. More importantly, Li-16(BH4)(13)I-3@g-C3N4-based Li batteries are compatible with S-C and FeF3 cathodes and MgH2 anodes and can achieve long-term cycling with Li4Ti5O12 anodes at a temperature range from 30 to 60 degrees C. The developed strategy of coupling halide substitution together with interface modifications may open a new avenue toward the development of LiBH4-based high ionic conductivity electrolytes for room-temperature all-solid-state Li batteries.

Automated summary

By synthesizing Li-16(BH4)(13)I-3@g-C3N4 through a combination of halide substitution and interface modifications, researchers achieved high ionic conductivity and excellent electrochemical stability. This electrolyte is compatible with various cathodes and anodes, allowing for long-term cycling with superior performance. This study may pave the way for the development of LiBH4-based high ionic conductivity solid-state Li batteries at room temperature.