Cation Segregation of A-Site Deficiency Perovskite La0.85FeO3-δ Nanoparticles toward High-Performance Cathode Catalysts for Rechargeable Li-O2 Battery.

Cation segregation of perovskite oxide is crucial to develop high-performance catalysts. Herein, we achieved the exsolution of α-Fe2O3 from parent La0.85FeO3-δ by a simple heat treatment. Compared to α-Fe2O3 and La0.85FeO3-δ, α-Fe2O3-LaFeO3- x achieved a significant improvement of lithium-oxygen battery performance in terms of discharge specific capacity and cycling stability. The promotion can be attributed to the interaction between α-Fe2O3 and LaFeO3- x. During the cycling test, α-Fe2O3-LaFeO3- x can be stably cycled for 108 cycles at a limited discharge capacity of 500 mAh g-1 at a current density of 100 mA g-1, which is remarkably longer than those of La0.85FeO3-δ (51 cycles), α-Fe2O3 (21 cycles), and mechanical mixing of LaFeO3 and α-Fe2O3 (26 cycles). In general, these results suggest a promising method to develop efficient lithium-oxygen battery catalysts via segregation.