Verification of the Fracture Mechanism of β"-Aluminas Caused by Large Current Density

Abstract

β"-Aluminas which transmit sodium ions and do not conduct electrons are expected to be practically applied for solid electrolytes and separators in sodium-sulfur batteries. It is known that large sodium-ion current density fractures β"-Aluminas instantly. For making this fracture mechanism clear, the temperature and thermal stress distribution in β"-Alumina occurred by transmitting sodium ions were calculated. Then using β"-Alumina tubes, experiments in which they were cracked by large current density were carried out. The values of thermal stress at these experiments were solved using upper calculation. These values were almost equal to those of β"-Aluminas' mechanical strength. The fracture mechanism of β"-Aluminas by transmitting large sodium-ion current density is supposed to be thermal stress occured by Joules' loss in β"-Aluminas.