Interfacial engineering of a MoS2–FeCoS2@NG nanocomposite: an efficient electrocatalyst for enhanced flexible zinc–air battery performance

Abstract

The efficient rational design, and prolonged and affordable catalyst synthesis from non-precious metals for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) pose a considerable obstacle in the development of future rechargeable zinc–air batteries. Herein, an interfacial engineering strategy is employed to construct a MoS₂–FeCoS₂ heterostructure decorated on a N-doped graphene sheet nanocomposite, which was synthesized by a simple and facile hydrothermal method. The optimal bifunctional electrocatalyst (MoS₂–FeCoS₂@NG) exhibits outstanding electrocatalytic performances for the OER (η₁₀ = 217 mV) and the ORR (0.65 V vs. RHE) with prolonged durability due to the interfacial synergistic effect. Furthermore, the MoS₂–FeCoS₂@NG catalyst was applied as an air cathode in both a rechargeable liquid and a flexible zinc–air battery. The liquid device exhibits an excellent power density of 130 mW cm⁻² at 217 mA cm⁻² and an ultralong cycle life of 1200 cycles. Most interestingly, the flexible quasi-solid-state zinc–air battery delivers improved power density and prolonged cycling stability over 1500 cycles at 5 mA cm⁻². This study presents a novel approach to develop a highly reversible bifunctional electrocatalyst for future rechargeable zinc–air batteries.