Journal of Power Sources, Vol.295, 167-174, 2015
Enhanced sintering of beta"-Al2O3/YSZ with the sintering aids of TiO2 and MnO2
beta-Al2O3 has been the dominated choice for the electrolyte materials of sodium batteries because of its high ionic conductivity, excellent stability with the electrode materials, satisfactory mechanical strength, and low material cost. To achieve adequate electrical and mechanical performance, sintering of beta-Al2O3 is typically carried out at temperatures above 1600 degrees C with deliberate efforts on controlling the phase, composition, and microstructure. Here, we reported a simple method to fabricate beta-Al2O3/YSZ electrolyte at relatively lower temperatures. With the starting material of boehmite, single phase of "-Al2O3 (3 can be achieved at as low as 1200 degrees C. It was found that TiO2 was extremely effective as a sintering aid for the densification of beta-Al2O3 and similar behavior was observed with MnO2 for YSZ. With the addition of 2 mol% TiO2 and 5 mol% MnO2, the beta-Al203/YSZ composite was able to be densified at as low as 1400 degrees C with a fine microstructure and good electrical/mechanical performance. This study demonstrated a new approach of synthesis and sintering of beta-Al2O3/YSZ composite, which represented a simple and low-cost method for fabrication of high-performance beta-Al2O3/YSZ electrolyte. Published by Elsevier B.V.