Effect of Chromium on electrochemical and mechanical properties of beta-Al2O3 solid electrolyte

Abstract

Abstract In order to improve the performance of the beta-Al2O3 solid electrolyte, the influence of Cr doping during the preparation of Na-beta-Al2O3 by solid state method was studied, the α-Al2O3 and Na2C2O4 was used as raw materials, and Li+ was added to stabilize β″ phase. The results showed that without Cr2O3 doping, the β″ phase content of the electrolyte was 92.28%, and the relative density was 99.07% of the theoretical density. The appropriate amount of Cr element could stabilize the β″ phase and refine the grain, when the doping amount of Cr2O3 was 0.15 wt%, the content of β″ phase could reach 97.93%, the relative density was 99.07%, the ionic conductivity was 0.082 S · cm−1 at 350 °C, and the bending strength was 253 Mpa. In addition, the excessive Cr element tends to gather in the grain boundary, resulting in the melting state and non-uniform size of the grains, and it will also hinder the formation of the β″ phase.