Pomegranate-like structured FeNi-nanodots@FeNi LDH composite as a high performance bifunctional catalyst for oxygen electrocatalytic reactions in zinc-air batteries

An efficient bifunctional oxygen catalyst for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial for the widespread application of rechargeable zinc-air batteries (ZABs) with high energy density and low-cost electrically. Herein, we report an effective pomegranate-like structured FeNi–N–C@FeNi LDH catalyst using Zeolitic Imidazolate Framework (ZIF-8) as precursor via pyrolysis and hydrothermal reactions. The as-prepared FeNi–N–C@FeNi LDH composite, consisting of FeNi-nanodots embedded in carbon matrix and metal layered double hydroxides (LDHs) as outer layer, exhibits preferable performance toward ORR (E_1/2 = 0.890V) and OER (E_{j = 10} = 1.535V) compared to precious metal-based catalysts. Moreover, when being applied in ZABs, the FeNi–N–C@FeNi LDH composite displays a high open-circuit voltage of 1.497 V and a durability of up to 100 h, demonstrating its great possibility in practical application.