Study on lithium/air secondary batteries-Stability of NASICON-type lithium ion conducting glass-ceramics with water

The water stability of the fast lithium ion conducting glass-ceramic electrolyte, Li1+x+yAlxTi2-xSiyP3-yO12 (LATP), has been examined in distilled water, and aqueous solutions of LiNO3, LiCl, LiOH, and HCl. This glass-ceramics are stable in aqueous LiNO3 and aqueous LiCl, and unstable in aqueous 0.1 M HCl and 1 M LiOH. In distilled water, the electrical conductivity slightly increases as a function of immersion time in water. The Li-Al/Li3-xPO4-yNy/LATP/aqueous 1 M LiCl/Pt cell, where lithium phosphors oxynitrides Li3-xPO4-yNy (LiPON) are used to protect the direct reaction of Li and LATP, shows a stable open circuit voltage (OCV) of 3.64V at 25 degrees C, and no cell resistance change for I week. Lithium phosphors oxynitride is effectively used as a protective layer to suppress the reaction between the LATP and Li metal. The waterstable Li/LiPON/LATP system can be used in Li/air secondary batteries with the air electrode containing water. (C) 2008 Elsevier B.V. All rights reserved.