Fe-MOF-Derived Efficient ORR/OER Bifunctional Electrocatalyst for Rechargeable Zinc–Air Batteries

Abstract

The construction of an efficient oxygen reduction reaction and oxygen evolution reaction (ORR/OER) bifunctional electrocatalyst is of great significance but still remains a giant challenge for high-performance metal-air batteries. In this study, uniform FeS/Fe₃C nanoparticles embedded in a porous N,S-dual doped carbon honeycomb-like composite (<i>abbr.</i> FeS/Fe₃C@NS-C-900) have been conveniently fabricated by pyrolysis of a single-crystal <b>Fe-MOF</b>, which has a low potential gap Δ<i>E</i> of ca. 0.72 V, a competitive power density of 90.9 mW/cm², a specific capacity as high as 750 mAh/g<i>_Zn</i>, and excellent cycling stabilities over 865 h (1730 cycles) at 2 mA/cm² when applied as a cathode material for rechargeable zinc-air batteries. In addition, the two series-linked Zn-air batteries successfully powered a 2.4 V LED light as a real power source. The efficient ORR/OER bifunctional electrocatalytic activity and long-term durability of the obtained composite might be attributed to the characteristic honeycomb-like porous structure with sufficient accessible active sites, the synergistic effect of FeS and Fe₃C, and the N,S codoped porous carbon, which provides a promising application potential for portable electronic Zn-air battery related devices.