Improving intermediate-temperature stability of BSCF by constructing high entropy perovskites

Abstract

High entropy perovskites bring more space for materials design in many fields. The stability of materials in thermodynamics can be improved by increasing the mixed entropy. In this work, a series of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) based high entropy perovskite (HEBSCF) were designed to improve the stability of BSCF at intermediate temperatures. The influence of high entropy composition on the lattice parameter, microstructure and stability of HEBSCF were investigated. The results show that HEBSCF can accommodate cations with large size differences. Compared with BSCF, doping elements at A site (HEBSCF-A), B site (HEBSCF-B) or both sites (HEBSCF-AB) can improve the mixed entropy. Among the three doped BSCF, HEBSCF-AB has the highest mixed entropy and shows stable oxygen permeation flux at 750 and 800 °C up to 300 h. No phase transition was observed on HEBSCF-AB after the long-term tests at intermediate temperatures. This research indicates that the high entropy stabilization strategy is feasible to improve the permeation stability of perovskite membranes by inhibiting phase transition.