A facile strategy to achieve high conduction and excellent chemical stability of lithium solid electrolytes

Lithium solid electrolytes have shown their potential for high-energy density batteries. The use of solid electrolytes will also be able to overcome safety issues associated with conventional carbonate-based electrolytes. However, achieving the combination of high ionic conductivity and excellent electrochemical stability in lithium solid electrolytes is still a major challenge. Herein we report a facile strategy to achieve high conduction and excellent electrochemical stability by the substitution of Cl for O based on the concept of bottleneck size and binding energy. The ionic conductivities of Li10.42Si1.5P1.5Cl0.08O11.92 and Li10.42Ge1.5P1.5Cl0.08O11.92 are 1.03 x 10(-5) S cm(-1) and 3.7 x 10(-5) S cm(-1) at 27 degrees C, respectively, which are 13 orders of magnitude higher than that of the pure Li3PO4, and 1 order of magnitude higher than that of the pristine Li10.5Si1.5P1.5O12. The electrochemical stability with metallic lithium is up to 9 V vs. Li+/Li, which is one of the widest electrochemical windows of solid electrolytes. This research also addresses the crystal structure, lithium ion migration mechanism, and battery performance.