Ni3Fe/Ni3Fe(OOH)x dynamically coupled on wood-derived nitrogen doped carbon as a bifunctional electrocatalyst for rechargeable zinc–air batteries

Abstract

Advances in rechargeable zinc–air batteries are hindered by the lack of efficient and economical oxygen electrocatalysts. Herein, a monolithic bifunctional catalyst is rationally constructed via an in situ growth of a FeNi₃ alloy on nitrogen-doped wood-derived carbon (FeNi₃@NWC). FeNi₃ alloy nanoparticles coupled with nitrogen-doped carbon expedite the catalytic activity toward oxygen reduction reaction (ORR) by promoting proton generation on FeNi₃ and transfer to nitrogen-doped carbon. The actual formation of Ni_1–xFe_xOOH on the surface of the FeNi₃ alloy effectively accelerates oxygen evolution reaction (OER) via the charge transfer with outstanding activity. The potential gap of only 0.68 V between ORR and OER of FeNi₃@NWC is achieved. The liquid zinc–air batteries (ZABs) with FeNi₃@NWC convey a robust lifetime of ∼266 h (800 cycles) with stable charging and discharging. Theoretical calculations manifest that the construction of double active sites through a synergistic mechanism between the FeNi₃ alloy and catalytically active carbon ignites the prominent catalytic activity with superior stability. This work provides remarkable inspiration for the rational design of biomass-derived efficient electrocatalysts and will facilitate the practical application of energy storage and conversion devices.