Graphene‐Encapsulated Bifunctional Catalysts with High Activity and Durability for Zn–Air Battery

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2023-07, Vol.19 (29), p.e2300551-n/a
• Main Authors: Ha, Seong‐Ji, Hwang, Jongha, Kwak, Myung‐Jun, Yoon, Jong‐Chul, Jang, Ji‐Hyun
• Format: Article
• Language: English
• Subjects: bifunctional catalysts; Carbon; carbon corrosion reaction; Catalysts; Chemical reduction; Durability; Electrocatalysts; Encapsulation; Energy conversion; Energy storage; Graphene; Graphitization; Hydrogels; Metal air batteries; Nanotechnology; oxygen catalysts; Oxygen evolution reactions; Oxygen reduction reactions; Rechargeable batteries; Transition metal alloys; transition metal nitrogen carbon; Zinc-oxygen batteries; Zn‐air batteries (ZABs)
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202300551

Carbon‐based electrocatalysts with both high activity and high stability are desirable for use in Zn–air batteries. However, the carbon corrosion reaction (CCR) is a critical obstacle in rechargeable Zn–air batteries. In this study, a cost‐effective carbon‐based novel material is reported with a high catalytic effect and good durability for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), prepared via a simple graphitization process. In situ growth of graphene is utilized in a 3D‐metal‐coordinated hydrogel by introducing a catalytic lattice of transition metal alloys. Due to the direct growth of few‐layer graphene on the metal alloy decorated 3d‐carbon network, greatly reduced CCR is observed in a repetitive OER test. As a result, an efficient bifunctional electrocatalytic performance is achieved with a low ΔE value of 0.63 V and good electrochemical durability for 83 h at a current density of 10 mA cm−2 in an alkaline media. Moreover, graphene‐encapsulated transition metal alloys on the nitrogen‐doped carbon supporter exhibit an excellent catalytic effect and good durability in a Zn–air battery system. This study suggests a straightforward way to overcome the CCR of carbon‐based materials for an electrochemical catalyst with wide application in energy conversion and energy storage devices. This study presents 3D graphene‐encapsulated alloys (Fe, Co, and Ni) onto a nitrogen‐doped carbon support (3d‐GMC) as a bifunctional electrocatalyst with much suppressed carbon corrosion for Zn–air batteries (ZABs). Excellent bifunctionality (ΔE = 0.63 V) and long‐term stability are demonstrated for the 3d‐GMC material.