Rhombohedral Li1+xYxZr2-x(PO4)3 Solid Electrolyte Prepared by Hot-Pressing for All-Solid-State Li-Metal Batteries

摘要

NASICON-type solid electrolytes with excellent stability in moisture are promising in all-solid-state batteries and redox flow batteries. However, NASIOCN LiZr (PO ) (LZP), which is more stable with lithium metal than the commercial Li Al Ti (PO ) , exhibits a low Li-ion conductivity of 10 S cm because the fast conducting rhombohedral phase only exists above 50 °C. In this paper, the high-ionic conductive rhombohedral phase is stabilized by Y doping at room temperature, and the hot-pressing technique is employed to further improve the density of the pellet. The dense Li Y Zr (PO ) pellet prepared by hot-pressing shows a high Li-ion conductivity of 9 × 10 S cm , which is two orders of magnitude higher than that of LiZr (PO ) . The in-situ formed Li P layer on the surface of Li Y Zr (PO ) after contact with the lithium metal increases the wettability of the pellet by the metallic lithium anode. Moreover, the Li Y Zr (PO ) pellet shows a relatively small interfacial resistance in symmetric Li/Li and all-solid-state Li-metal cells, providing these cells a small overpotential and a long cycling life.