Production of Electrolyte Membranes for Sodium-beta Alumina Batteries

The increasing boost towards renewable energy and sustainable mobility have grown the research interest in sodium-beta alumina batteries owing to their high theoretical energy density, high round trip efficiency and good cycle life. These electrochemical devices store electrical energy via sodium ion transport across a ?''-Al2O3 solid electrolyte at relative high temperatures (250-350°C). The ceramic membrane acts simultaneously as both the electrolyte and the separator between the anode, molten metallic sodium, and the cathode, molten-sulfur (Na-S battery) or metal halide plus NaAlCl4 (ZEBRA battery). The ceramic electrolyte is a component of crucial importance for sodium-beta alumina batteries. The process needed to produce the electrolytic compartment has a key role to enhance and adapt the batteries performances to the specific requirements for stationary regime applications. Each minimal composition or process deviation strongly influences the final properties of the device. In this work, ?"-alumina membranes were produced by die pressing and tape casting. Each process was carefully optimized in order to obtain electrolytic membranes with suitable characteristics. The critical issues and advantages linked to the two shaping processes were underlined and compared.