Water Durable Lithium Ion Conducting Composite Membranes from the Li[sub 2]O-Al[sub 2]O[sub 3]-TiO[sub 2]-P[sub 2]O[sub 5] Glass-Ceramic

Abstract

In this paper, processing and properties of water durable solid electrolyte membranes prepared from a glass-ceramic powder in the Li2O-Al2O3-TiO2-P2O5Li2O-Al2O3-TiO2-P2O5 system are reported. Specifically, ionic conductivity, microstructure, and water stability of 150to350μm150to350μm thick membranes of the glass-ceramic and its composite with polyethylene are investigated and discussed. The grains (crystallites) of the glass-ceramic show liquidlike conductivity at ambient temperature, whereas the grain boundary conductivity is lower by a factor of about 3. The ratio between the grain and grain boundary conductivities in the temperature range of 213to300K213to300K varies by a factor of 3 to 14. The lower the temperature, the larger the ratio. The difference in conductivities is explained on the basis of crystallographic mismatch and the existence of crystalline AlPO4AlPO4 at the grain boundary. The membranes were very stable in tap water. The polyethylene infiltration further improved water stability with little impact on conductivity.