Cation Segregation of A-Site Deficiency Perovskite La 0.85 FeO 3-δ Nanoparticles toward High-Performance Cathode Catalysts for Rechargeable Li-O 2 Battery.

Cation segregation of perovskite oxide is crucial to develop high-performance catalysts. Herein, we achieved the exsolution of α-Fe ₂ O ₃ from parent La _0.85 FeO _3-δ by a simple heat treatment. Compared to α-Fe ₂ O ₃ and La _0.85 FeO _3-δ , α-Fe ₂ O ₃ -LaFeO _{3- 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-Fe ₂ O ₃ and LaFeO _{3- x} . During the cycling test, α-Fe ₂ O ₃ -LaFeO _{3- 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 La _0.85 FeO _3-δ (51 cycles), α-Fe ₂ O ₃ (21 cycles), and mechanical mixing of LaFeO ₃ and α-Fe ₂ O ₃ (26 cycles). In general, these results suggest a promising method to develop efficient lithium-oxygen battery catalysts via segregation.