Mechanochemical Synthesis of High Lithium Ion Conducting Materials in the System Li₃N−SiS₂

High lithium ion conducting materials were mechanochemically synthesized using Li 3 N and SiS 2 as starting materials. The obtained Li 3 N−SiS 2 materials were almost amorphous; the amorphous phases consisted of SiS 4 tetrahedral units with no edge sharing and the local structure was very similar to that of mechanically milled Li 2 S−SiS 2 amorphous materials. High lithium ion conducting Li 3 N−SiS 2 materials could be synthesized in very short milling periods, around 20 min, since explosive reactions occurred in this system. The mechanically milled 40Li 3 N·60SiS 2 (mol %) material exhibited excellent properties as solid electrolytes such as high conductivity around 10 - 4 S cm - 1 at room temperature, unity of lithium ion transport number, and a wide electrochemical window of about 10 V vs Li + /Li.