Enhanced Oxygen Evolution and Zinc-Air Battery Performance via Electronic Spin Modulation in Heterostructured...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Optimizing electronic spin configuration is a key strategy for improving catalytic activity and selectivity, particularly in the oxygen evolution reaction (OER).
• Current methods for electronic spin modulation often rely on external magnetic fields, limiting their practical applicability.
• Developing intrinsic spin modulation strategies is crucial for advancing catalytic technologies.

Purpose of the Study:

• To engineer Ni/MnFe2O4 heterojunctions for intrinsic spin modulation in electrocatalysis.
• To investigate the surface reconstruction and electronic spin state of NiOOH/MnFeOOH during OER.
• To evaluate the electrocatalytic performance of the engineered heterojunctions for OER and their application in zinc-air batteries.

Main Methods:

• Fabrication of Ni/MnFe2O4 heterojunctions.
• In-situ surface reconstruction to NiOOH/MnFeOOH during OER.
• Electrochemical characterization of OER performance (overpotential measurements).
• Fabrication and testing of rechargeable zinc-air batteries.
• Density Functional Theory (DFT) calculations to rationalize performance.

Main Results:

• The NiOOH/MnFeOOH surface exhibits a high spin state of Ni, regulating adsorption energies and enabling spin alignment of oxygen intermediates.
• The engineered electrocatalysts achieved excellent OER performance with a low overpotential of 261 mV at 10 mA cm-2.
• Zinc-air batteries based on Ni/MnFe2O4 demonstrated a high open circuit potential of 1.56 V and over 1000 cycles of stability.
• DFT calculations confirmed that optimal spin states facilitate spin-selected charge transport and reduce the oxygen evolution energy barrier.

Conclusions:

• Intrinsic spin modulation via Ni/MnFe2O4 heterojunction engineering is an effective strategy for boosting OER performance.
• The high spin state of Ni in NiOOH/MnFeOOH plays a critical role in optimizing reaction kinetics and intermediates.
• This work offers valuable insights for designing next-generation electrocatalysts by leveraging spin polarization modulation.