Method for increasing the crystal phase fraction of Na--alumina by control of firing schedule in the production process of Na-beta-alumina solid electrolyte tube

摘要

The present invention relates to a method of solid electrolyte of a secondary bettery with increased beta''-alumina crystal phase fraction by sintering NaAlO2 and beat-Al2O3 at a temperature greater than the eutectic point and by annealing at a low temperature during a plasticizing process for producing Na+-beta-alumina, and the solid electrolyte produced by the method. More specifically the present invention provides a method to produce a Na+-beta-alumina sintered body which comprises the following steps: mixing Na2CO3 and Li2CO3 using alpha-alumina and a ball-milling process; calcining the mixture to synthesize sodium aluminate and lithium aluminate, and mixing; molding the mixture through a cold isostatic press; sintering the molded mixture at a temperature greater than the eutectic point f the NaAlO2 and beta-Al2O3; and annealing the mixture.