On the way to transform lithium amide (LiNH2) into lithium imide (Li2NH) by releasing H2, the 1:1 molar mixture of LiNH2-LiH forms cubic (F m 3 m) non-stoichiometric complex hydride phases (Li1+ xNH2- x; 0 < x < 1) that co-exist with the tetragonal (I 4) LiNH2 and with the cubic (F d 3 m) Li2NH, respectively, at the early and at the advanced stage of the dehydrogenation. The change in LiNH2 → Li2NH may be viewed as a mechanism which continuously fills up the vacant Li sites of the tetragonal structure and, in a parallel process, transforms the anions [NH2]- → [NH]2-. The Li-N-H system, thus formed, by releasing >6 wt. % H2 can offer high Li-ionic conductivity (>10-4 S·cm-1 at room temperature) having an electrochemical stability window >5 V. The study suggests that the Li-N-H system may be a prospective electrolyte in the all-solid-state Li-ion battery, in addition to its use as a reversible hydrogen storage material.
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