Synthesis of Fe2O3 Nanoparticle-Decorated N-Doped Reduced Graphene Oxide as an Effective Catalyst for Zn-Air Batteries

The advancement of Zn-air batteries requires effective and inexpensive electrocatalysts that facilitate the oxygen reduction reaction (ORR) and evolution reaction (OER). Herein, we report an effective electrocatalyst of Fe 2 O 3 nanoparticle-decorated N-doped reduced graphene oxide (Fe 2 O 3 /N-rGO), in which porous Fe 2 O 3 nanoparticles of ∼37 nm are anchored on the N-rGO surface uniformly. In an alkaline solution, the synthesized Fe 2 O 3 /N-rGO affords superior ORR and OER activity in comparison with Fe 2 O 3 and N-rGO, demonstrating the reinforced synergistic effect. Moreover, it exhibits a comparable limiting current density and a higher current retention ratio in the ORR than commercial Pt/C. A Zn-air battery with Fe 2 O 3 /N-rGO delivers a peak power density of 80.1 mW cm −2 , and the energy density reaches 730.2 Wh kg Zn −1 . In addition, stable voltage gaps of ∼0.91 V during discharge and charge are achieved at 5 mA cm −2 , and the energy efficiency is maintained at ∼60% over 120 cycles, illustrating the remarkable stability for rechargeable Zn-air batteries.