Designing High-Quality Electrocatalysts Based on CoO:MnO2@C Supported on Carbon Cloth Fibers as Bifunctional Air Cathodes for Application in Rechargeable Zn-Air Battery

Mohammad-Reza Zamani-Meymian; Karim Khanmohammadi Chenab; Hamed Pourzolfaghar

doi:10.1021/acsami.2c16826

Designing High-Quality Electrocatalysts Based on CoO:MnO₂@C Supported on Carbon Cloth Fibers as Bifunctional Air Cathodes for Application in Rechargeable Zn-Air Battery

ACS Appl Mater Interfaces. 2022 Dec 21;14(50):55594-55607. doi: 10.1021/acsami.2c16826. Epub 2022 Dec 7.

Authors

Mohammad-Reza Zamani-Meymian¹, Karim Khanmohammadi Chenab^{1

2}, Hamed Pourzolfaghar^{1

3}

Affiliations

¹ Department of Physics, Iran University of Science and Technology, Tehran16846-13114, Iran.
² Department of Chemistry, Iran University of Science and Technology, Tehran16846-13114, Iran.
³ Department of Chemical Engineering, National Chung Cheng University, Min-Hsiung, Chia-yi62102, Taiwan.

PMID: 36475585
DOI: 10.1021/acsami.2c16826

Abstract

To achieve the requirements of rechargeable Zn-air batteries (ZABs), designing efficient, bifunctional, stable, and cost-effective electrocatalysts is vital for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which still are struggling with unsolved challenges. The present research provides a concept based on the nanoscale composites which were engineered by using MnO₂@C, CoO@C, and CoO:MnO₂@C bifunctional electrocatalysts for fabrication of uniform carbon cloth (CC)-based electrodes. The CoO:MnO₂@C electrocatalyst represented more efficient electrochemical properties through ORR and OER processes with superior positive half-wave potential (E_1/2 = 0.78 V) and better limiting current density (i = 1.10 mA cm^-2) in comparison with MnO₂@C (E_1/2 = 0.71 V, i = 0.92 mA cm^-2) and CoO@C (E_1/2 = 0.69 V, i = 0.86 mA cm^-2) electrocatalysts. For the rechargeable ZABs fabricated by using CoO:MnO₂@C-CC as an O₂-breathing cathode, the specific capacity (SC), peak power density (P), open-circuit voltage (E_OCV), and gap of charge/discharge voltage resulted in values of 520 mAh g_Zn^-1, 210.0 mW cm^-2, and 1.45 and 0.45 V, respectively, that afforded greater electrochemical characters than what was obtained for ZABs based on MnO₂@C-CC (410 mAh g_Zn^-1, 195.0 mW cm^-2, 1.38 and 0.44 V) and CoO@C-CC (440 mAh g_Zn^-1, 165.0 mW cm^-2, 1.15 and 0.54 V). At the same time, lower E_i=10 (= 1.45 V) implied a more efficient OER in alkaline electrolyte solution for CoO:MnO₂@C than MnO₂@C (E_i=10 = 1.50 V) and CoO@C (E_i=10 = 1.39 V). Based on cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and X-ray photoelectron spectroscopy (XPS) results, it could be stated that the CoO:MnO₂@C catalytic surface could experience 30 and 32% lower charge transfer resistance (R_ct = 13.9 Ω) than MnO₂@C (R_ct = 20.1 Ω) and CoO@C (R_ct = 29.7 Ω), respectively, which empowers an enhancement in ORR/OER performance. Prominently, the design concept of proposed electrocatalysts could suggest clear horizon for the synthesis and development paradigms of bifunctional catalysts for energy storage materials and devices.

Keywords: bifunctional electrocatalyst; charge transfer; oxygen evolution reaction; oxygen reduction reaction; rechargeable Zn-air battery.