Lattice oxygen activation enabled by Fe doping in double perovskite oxides for efficient zinc–air batteries

Abstract

Developing efficient and durable electrocatalysts for the oxygen evolution reaction (OER) is crucial to advancing rechargeable zinc–air batteries (ZABs). In this work, we rationally design a series of Fe-doped double perovskite oxides (BaPrCo_2−xFe_xO_5+δ, denoted BPCF-x) to elucidate the interplay among Fe incorporation, lattice oxygen activity, and OER performance. Comprehensive structural and spectroscopic analysis reveal that Fe doping effectively tailors the electronic configuration and modulates the oxygen vacancy concentration, thereby accelerating charge transfer kinetics. Notably, BPCF-0.8 exhibits the lowest overpotential of 295 mV at 10 mA cm⁻² and a Tafel slope of 45 mV dec⁻¹, outperforming the pristine BPC catalyst. Optimized Fe incorporation promotes the lattice oxygen mechanism pathway while preserving structural integrity, as confirmed by OER tests in various pH electrolytes. Furthermore, the ZAB using BPCF-0.8 as the air cathode catalyst delivers high power density and excellent long-term durability, sustaining stable operation for over 500 h. This work elucidates how Fe doping activates lattice oxygen and balances oxygen vacancies, providing valuable insights into cation substitution engineering and lattice oxygen regulation in perovskite electrocatalysts.