Surface modification of Li1.3Al0.3Ti1.7(PO4)3 ceramic electrolyte by Al2O3-doped ZnO coating to enable dendrites-free all-solid-state lithium-metal batteries

The Na super-ionic conductor (NASICON) type solid electrolytes Li1.3Al0.3Ti1.7(PO4)(3) (LATP) are of increasing interest because of their high total ionic conductivity and excellent stability against moist air. However, they are not stable when contacting with lithium metal because of the rapid Ti4+ reduction by Li metal, which greatly restrict their application in lithium batteries. Here, we propose a Al2O3-doped ZnO (AZO) surface coating method by magnetron sputtering to improve the stability of the Li1.3Al0.3Ti1.7(PO4)(3) electrolyte against the attack of lithium-metal anode and to avoid the growth of lithium dendrite. The Al2O3-doped ZnO coating of the electrolyte Li1.3Al0.3Ti1.7(PO4)(3) demonstrates high chemical stability against the attack of lithium-metal in a wide electrochemical potential ranges ( > 5 V), as well as an excellent performance of suppressing of lithium dendrites. Furthermore, the Al2O3-doped ZnO coated Li1.3Al0.3Ti1.7(PO4)(3) was found to be the candidate electrolyte for the all-solid-state lithium battery. An all-solid-state Li/LiFePO4 battery with Al2O3-doped ZnO coated Li1.3Al0.3Ti1.7(PO4)(3) as the solid electrolyte shows good cyclability and a high columbic efficiency for 50 charge/discharge cycles. Furthermore, the surface-modified electrolyte Li1.3Al0.3Ti1.7(PO4)(3) by Al2O3-doped ZnO coating also enables the lithium metal battery to exhibit extremely long cycling for nearly 1000 h due to the ability of suppressing of lithium dendrites.