Li/Polymer Electrolyte/Water Stable Lithium-Conducting Glass Ceramics Composite for Lithium-Air Secondary Batteries with an Aqueous Electrolyte

A water-stable Li metal anode with water-stable lithium-conducting glass ceramics, Li(1+x+y)Ti(2-x)Al(x)Si(y)P(3-y)O(12) (LTAP), and a lithium-conducting polymer electrolyte, PEO(18)Li(CF(3)SO(2))(2)N (PEO(18)LiTFSI), was proposed as the lithium anode for lithium-air batteries with an aqueous solution at the air electrode. LTAP was unstable when in direct contact with Li metal, and the cell resistance of Li/LTAP/Li rapidly increased as a function of the contact time. The Li/PEO(18)LiTFSI/LTAP/PEO(18)LiTFSI/Li symmetrical cell showed no change in the total resistance (around 800 Omega cm(2) at 60 degrees C) over a period of 1 month. The PEO(18)LiTFSI membrane served as a protective interlayer to suppress the reaction between the water-stable glass ceramics LTAP and Li metal effectively. The Li/PEO(18)LiTFSI/LTAP/aqueous LiCl/Pt air cell showed a stable open-circuit voltage of 3.70 V at 60 degrees C for 2 months. The open-circuit voltage was comparable with that calculated from the cell reaction of 2Li+1/2O(2)+H(2)O=2LiOH. The cell exhibited a favorable discharge and charge performance at 0.25 mA cm(-2) and 60 degrees C. (c) 2008 The Electrochemical Society. [DOI: 10.1149/1.2990717] All rights reserved.