Exploring Cu-Doped Co3O4 Bifunctional Oxygen Electrocatalysts for Aqueous Zn-Air Batteries

Behera, A and Seth, D and Agarwal, M and Haider, MA and Bhattacharyya, AJ (2024) Exploring Cu-Doped Co3O4 Bifunctional Oxygen Electrocatalysts for Aqueous Zn-Air Batteries. In: ACS Applied Materials and Interfaces, 16 (14). pp. 17574-17586.

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Abstract

The efficiency of oxygen electrocatalysis is a key factor in diverse energy domain applications, including the performance of metal-air batteries, such as aqueous Zinc (Zn)-air batteries. We demonstrate here that the doping of cobalt oxide with optimal amounts of copper (abbreviated as Cu-doped Co3O4) results in a stable and efficient bifunctional electrocatalyst for oxygen reduction (ORR) and evolution (OER) reactions in aqueous Zn-air batteries. At high Cu-doping concentrations (�5), phase segregation occurs with the simultaneous presence of Co3O4 and copper oxide (CuO). At Cu-doping concentrations �5, the Cu ion resides in the octahedral (Oh) site of Co3O4, as revealed by X-ray diffraction (XRD)/Raman spectroscopy investigations and molecular dynamics (MD) calculations. The residence of Cu@Oh sites leads to an increased concentration of surface Co3+-ions (at catalytically active planes) and oxygen vacancies, which is beneficial for the OER. Temperature-dependent magnetization measurements reveal favorable d-orbital configuration (high eg occupancy � 1) and a low � high spin-state transition of the Co3+-ions, which are beneficial for the ORR in the alkaline medium. The influence of Cu-doping on the ORR activity of Co3O4 is additionally accounted in DFT calculations via interactions between solvent water molecules and oxygen vacancies. The application of the bifunctional Cu-doped (�5) Co3O4 electrocatalyst resulted in an aqueous Zn-air battery with promising power density (=84 mW/cm2), stable cyclability (over 210 cycles), and low charge/discharge overpotential (=0.92 V). © 2024 American Chemical Society.

Item Type:	Journal Article
Publication:	ACS Applied Materials and Interfaces
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society.
Keywords:	Cobalt compounds; Copper oxides; Density functional theory; Electrocatalysis; Electrocatalysts; Electrolytic reduction; Heavy ions; Molecular oxygen; Molecules; Oxygen vacancies; Reaction kinetics; Zinc air batteries; Zinc compounds, Bi-functional; Cu-doped; Cu-doped co3O4, OER/ORR; Cu-doping; Density functional theory, molecular dynamic; Density-functional-theory; Doping concentration; Eg occupancy; Oxygen electrocatalysis; Zinc-air battery, Molecular dynamics, cobalt; copper; copper ion; copper oxide; oxygen; solvent; water; zinc, air; article; controlled study; density; density functional theory; electrocatalysis; molecular dynamics; Raman spectrometry; reduction (chemistry); temperature; X ray diffraction
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research
Date Deposited:	10 Jul 2024 07:46
Last Modified:	10 Jul 2024 07:46
URI:	http://eprints.iisc.ac.in/id/eprint/84786

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