Y and Fe co-doped LaNiO3 perovskite as a novel bifunctional electrocatalyst for rechargeable zinc-air batteries

Abstract

Perovskite oxides are widely regarded as the promising air electrode catalytic materials for zinc-air batteries (ZABs). In the present work, A-site Y and B-site Fe co-doped La0.85Y0.15Ni0.7Fe0.3O3 perovskite catalyst was prepared by self-propagating high-temperature synthesis, and this material was evaluated as a bifunctional electrocatalyst for ZABs. The effect of co-doping on crystal structure and reaction activities, which can promote oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), was investigated. Results show that Y and Fe co-doping substantially improved the ORR and OER of LaNiO3. In comparison with LaNiO3, the ORR performance of La0.85Y0.15Ni0.7Fe0.3O3 exhibited a higher limiting current density (3.8 mA cm−2 at 0.4 V vs. RHE) and more positive onset potential (0.75 V vs. RHE) at 1600 rpm. It also had an excellent OER performance of 1.74 V vs. RHE at 10 mA cm−2. When La0.85Y0.15Ni0.7Fe0.3O3 was used as an air electrode catalyst for ZABs, it exhibited a high power density of 93.6 mW cm−2, which increased by 84.8% compared with that of LaNiO3. Moreover, the full cell with La0.85Y0.15Ni0.7Fe0.3O3 air electrode catalyst was operated for more than 80 h, maintaining good stability. Therefore, La0.85Y0.15Ni0.7Fe0.3O3 can be used as a promising bifunctional air electrode catalyst for ZABs. The characterization analysis reveals that A-site Y and B-site Fe co-doped catalyst transforms crystal structure from trigonal system to cubic system, retain the valence state of Ni3+ and increases the contents of O22−/O−, and these properties are more conducive for LaNiO3 catalysis.