Chemical Expansivity of Electrochemical Ceramics

Abstract

To better understand thermal strain in electrochemical ceramics, the temperature and oxidation‐state dependence of lattice volume in La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ (LSCF) were measured. Large values in the apparent thermal expansion coefficient at high temperature (>50 ppm/°C) were caused by changes in oxygen content, not increases in thermal expansivity. This material can be described using an improved thermodynamic formalism that incorporates a new physical property, the chemical expansivity . Our approach opens new avenues for modeling stress and strain in materials, probing defect structure, and analyzing transport and kinetic properties.