Interfacial Defect Engineering for Improved Portable Zinc-Air Batteries with a Broad Working Temperature

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing efficient bifunctional catalysts is crucial for advanced energy storage systems.
• Oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts often require distinct active sites, limiting their integrated application.
• Defect engineering in nanomaterials offers a promising strategy to enhance catalytic activity.

Purpose of the Study:

• To synthesize and characterize atomic-thick NiO/CoO transition interfacial nanowires (TINWs) as a bifunctional catalyst.
• To investigate the electrocatalytic performance of NiO/CoO TINWs for both OER and ORR.
• To evaluate the application of NiO/CoO TINWs in zinc-air batteries under various temperature conditions.

Main Methods:

• Synthesis of NiO/CoO transition interfacial nanowires (TINWs).
• Electrochemical characterization including cyclic voltammetry and polarization curves for OER and ORR.
• Density functional theory (DFT) calculations to understand the catalytic mechanism.
• Assembly and testing of zinc-air batteries using NiO/CoO TINWs as air electrodes.

Main Results:

• NiO/CoO TINWs exhibit abundant defect sites and an electron-rich interfacial region.
• Excellent electroactivity and durability were observed for both OER and ORR.
• DFT calculations revealed a fast-redox rate with a lower activation barrier for electron transfer due to interfacial effects and defects.
• Zinc-air batteries assembled with NiO/CoO TINWs achieved a high specific capacity (842.58 mAh g_Zn^-1) and energy density (996.44 Wh kg_Zn^-1).
• The air electrode demonstrated long-term stability (>33 h) and superior performance at temperatures ranging from -10°C to 80°C.

Conclusions:

• Atomic-thick interfacial engineering in NiO/CoO TINWs creates highly active sites for bifunctional OER/ORR catalysis.
• The synergistic effect between the NiO/CoO interface and defect sites significantly enhances electrocatalytic performance.
• NiO/CoO TINWs are promising candidates for high-performance, wide-temperature-range zinc-air batteries.