Effects of aluminum source on nonaqueous precipitation synthesis of β''-Al2O3 and its mechanism research

Abstract

β''-Al₂O₃ solid electrolyte (Beta'' Alumina Solid Electrolyte, BASE) ionic migration channels forming main methods typically rely on poreforming agents, freeze casting, and intermediate-stage sintering. However, it is difficult to form uniformly distributed ionic migration channels. This work designs a novel facile nonaqueous precipitation method to promote the formation of uniform ionic migration channels in BASE. In situ formed aluminum isopropoxide acts as polymerization self catalytic promoter to promote the de-etherification heterogeneous polymerization reaction between aluminum isopropoxide and sodium ethoxide, with the formation of a polymer product with Na-O-Al as the skeleton and uniform elemental distribution. The uniform distributed in-situ carbon at 1150 °C with a mass fraction of about 4.11 % promotes the formation of uniformly distributed Na-ions migration channels with a diameter of 0.005–1 μm when sintered at 1600 °C. These migration channels ensure migration rate of Na-ions with the ionic conductivity of BASE of 0.029 S/cm at 300 °C.