A NiFe/NiSe2 heterojunction bifunctional catalyst rich in oxygen vacancies introduced using dielectric barrier discharge plasma for liquid and flexible all-solid-state rechargeable Zn–air batteries

Abstract

Herein, a nitrogen doped carbon nanotube supported NiFe/NiSe₂ heterostructure rich in oxygen vacancies (DBD-NiFe/NiSe₂@NCNT) is successfully synthesized using atmospheric pressure dielectric barrier discharge plasma. It exhibits superior bifunctional catalytic activity towards the OER (η = 292 mV@10 mA cm⁻²) and ORR (E_1/2 = 0.811 V), with a ΔE as low as 0.711 V in 0.1 M KOH electrolyte, outperforming most of the ones previously reported in the literature. Through physical structure characterization, electrochemical properties and DFT calculation studies, the unique heterostructure and oxygen vacancies/defects that synergistically promote the catalytic process and greatly improve the catalytic performance were verified. Impressively, the as-assembled rechargeable ZAB based on DBD-NiFe/NiSe₂@NCNT as an electrocatalyst obtains a remarkable maximum power density of 131.61 mW cm⁻² and an exceptional stability for 1000 cycles at 10 mA cm⁻². Furthermore, the DBD-NiFe/NiSe₂@NCNT-based flexible all-solid-state ZAB revealed excellent performance with robust flexibility. This work provides worthy insights into the search for high-efficiency and low-cost energy storage and conversion devices.