NiFe-LDH Loaded on N-doped Paulownia-Derived Carbon as Bifunctional Oxygen Electrocatalyst for Rechargeable Zinc-Air Batteries

Abstract

Rational design of low-cost and high active bifunctional oxygen electrocatalysts is necessary for advancing the performance of rechargeable Zn-air batteries (RZABs).Herein, 2D NiFe layered double hydroxide (NiFe-LDH) nanosheets supported on 3D N-doped biomass(Paulownia wood)-derived carbon (NBC), NiFe-LDH@NBC, was prepared by pyrolysis and in-situ electric field assistant deposit. The half-wave potential (E1/2) of oxygen reduction reaction (ORR) on NiFe-LDH/NBC is 0.85 V, with a maximum current density of 5.90 mA cm -2 . The potential of oxygen evolution reaction (OER) at j = 10 mA cm -2 (Ej=10) is 1.47 V. The potential difference (ΔE) between E1/2 of ORR and Ej=10 of OER reaches to 0.62 V, lower than most similar catalysts previously reported. The aqueous RZABs assembled with NiFe-LDH/NBC as cathode electrocatalyst show a high peak power density of 155.9 mW cm -2 and excellent durability of over 360 h. The hierarchical porous structure of the carbon support accelerates electron transfer and mass transport during the reaction, and the strong coupling interaction between NBC and NiFe-LDH enhances the overall catalytic performance. This work provides a strategy for rational design of highly efficient and durable non-noble metal catalysts for RZAB technologies.