Interface Electronic Modulation of Monodispersed Co Metal-Co₇Fe₃ Alloy Heterostructures for Rechargeable Zn–Air Battery

Abstract

Engineering heterointerfaces between metal and alloy to facilitate charge transfer would be an attractive strategy for superefficient electrocatalysis. Herein, a simple xerogel-pyrolysis strategy has been designed to prepare an advanced bifunctional electrocatalyst, Co/Co 7 Fe 3 confined by a porous N-doped carbon nanosheets/CNTs composite (Co/Co 7 Fe 3 @PNCC). The formative Co/ Co 7 Fe 3 heterostructure promoted the charge transfers from metal Co to active alloy Co 7 Fe 3 , thus reducing the energy barrier of the oxygen reduction reaction and improving the catalytic kinetics and active surface area for the oxygen evolution reaction. The PNCC provided monodispersed confined space for Co/Co 7 Fe 3 particles, which also owned a high specific surface area for ions/gases diffusion. Therefore, Co/Co 7 Fe 3 @PNCC exhibited excellent bifunctional oxygen catalysis activities and durability with an ultralow polarization gap (ΔE) of only 0.64 V. When practically adopted as an air electrode in ZAB, a large open-circuit voltage of 1.534 V, a maximum power density of 211.82 mW cm −2 , an ultrahigh specific capacity of 807.33 mAh g −1 , and superior durability over 800 h were obtained. This catalyst design concept offers a facile strategy toward modulating electronic structure to achieve efficient bifunctional electrocatalysts for ZAB.

Microenvironment Tailoring of NiCo Alloys Coupled with FePc as Efficient Bifunctional Catalysts for High-Rate Zn-Air Batteries

“…Non-noble metal alloy materials (such as NiCo, − FeCo, , NiFe, , and CoCu) have become promising cost-effective alternative oxygen electrocatalysts due to their high electron mobility, high catalytic selectivity, and activity in OER. , Although the abundant valence-state changes are facilitated by the lattice strain differences on the two different metals in the alloy catalyst, , the regulation ability is limited and even uncontrollable due to the natural feature of the surface oxidation. In addition, the catalytic activity and stability of the metal alloy electrocatalyst are greatly impacted due to the corrosive environment of acidic or alkaline electrolytes .…”