NASICON Li1.2Mg0.1Zr1.9(PO4)3 Solid Electrolyte for an All-Solid-State Li-Metal Battery

A thin solid electrolyte with a high Li(+)conductivity is used to separate the metallic lithium anode and the cathode in an all-solid-state Li-metal battery. However, most solid Li-ion electrolytes have a small electrochemical stability window, large interfacial resistance, and cannot block lithium-dendrite growth when lithium is plated on charging of the cell. Mg(2+)stabilizes a rhombohedral NASICON-structured solid electrolyte of the formula Li1.2Mg0.1Zr1.9(PO4)(3)(LMZP). This solid electrolyte has Li-ion conductivity two orders of magnitude higher at 25 degrees C than that of the triclinic LiZr2(PO4)(3).Li-7 and(6)Li NMR confirm the Li-ions in two different crystallographic sites of the NASICON framework with 85% of the Li-ions having a relatively higher mobility than the other 15%. The anode-electrolyte interface is further investigated with symmetric Li/LMZP/Li cell testing, while the cathode-electrolyte interface is explored with an all-solid-state Li/LMZP/LiFePO(4)cell. The enhanced performance of these cells enabled by the Li1.2Mg0.1Zr1.9(PO4)(3)solid electrolyte is stable upon repeated charge/discharge cycling.