Electronic Structure Engineering in NiFe Sulfide via A Third Metal Doping as Efficient Bifunctional OER/ORR Electrocatalyst for Rechargeable Zinc‐Air Battery

Abstract

Ti, V, Cr, Mn, Co, and Cu, have been investigated as a third dopant in NiFe sulfide for enhanced oxygen evolution reaction (OER)/oxygen reduction reaction (ORR). The effects of dopant on surface electronic structure, conductivity, and thermodynamic barrier of reaction are addressed and discussed. For the OER, X‐ray photoelectron spectroscopy analysis shows that electron transferring from the Ni to the dopants enhances the catalytic performance of the sulfide. Cu doped NiFe sulfide exhibits the best OER performance. For the ORR, density functional theory calculation indicates that Ti, V, Mn, Co, and Cu upshift the d‐band center (ɛd), while Cr downshifts the ɛd. Among the dopants, V leads to optimized electronic structure modification, giving optimized adsorption energy of *O on the Ni, the lowest rate determining step ΔG1, and the best ORR activity. By considering E10‐E1/2 together with the maximum current density of the OER and limited diffusion current density of the ORR, NiFeVS exhibits the best OER/ORR bifunctionality. The performance of NiFeVS as a cathodic catalyst has also been evaluated in a zinc air battery, demonstrating a specific capacity of 698 mAh g−1, maximum power density of 190 mW cm−2, and a superior cycle stability of 2400 cycles (400 h).

Hierarchical Porous Carbon Supported Co2P2O7 Nanoparticles for Oxygen Evolution and Oxygen Reduction in a Rechargeable Zn–Air Battery

“…In light of growing global demand for energy and the heightened attention to environmental pollution issues, energy conversion and storage technologies, particularly fuel cells and metal-air batteries, have garnered significant interest due to their notable energy efficiency and environmental protection characteristics. − However, the most formidable challenge associated with these technologies is the relatively slow kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which occur alternately during the discharge and charge processes. Furthermore, the multistep four-electron transfer in the electrochemical process of zinc–air batteries (ZABs) has typically been constrained by a large potential gap (>0.85 V) and low energy efficiency. − Currently, the majority of commercial ORR and OER catalysts are based on noble metal materials, such as Pt and RuO 2 . However, the scarcity, high cost, and stability issues of precious metals limit their large-scale application.…”

Cu Regulating the Bifunctional Activity of Co-O Sites for the High-Performance Rechargeable Zinc-Air Battery

“…Consequently, the ORR E 1/2 was increased from 0.77 to 0.84 V. The OER overpotential was reduced to 268 from 329 mV 17. Sari et al showed that V reduced the Ni 2+ /Ni 3+ ratio to optimize the electronic structure of the Ni active site and obtain a ZAB's superior cycle stability of 2400 cycles at a current density of 10 mA cm −2 18. Zhang et al proposed a model etching strategy to increase the Co 2+ /Co 3+ ratio of Co 3 O 4 19.…”