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Ultrathin Cobalt Oxide Layers as Electrocatalysts for High‐Performance Flexible Zn–Air Batteries
Author(s) -
Zhou Tianpei,
Xu Wanfei,
Zhang Nan,
Du Zhiyi,
Zhong Chengan,
Yan Wensheng,
Ju Huanxin,
Chu Wangsheng,
Jiang Hong,
Wu Changzheng,
Xie Yi
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201807468
Subject(s) - materials science , overpotential , graphene , electrocatalyst , battery (electricity) , oxygen evolution , catalysis , substrate (aquarium) , bifunctional , oxide , cobalt , chemical engineering , cobalt oxide , nanotechnology , electrochemistry , electrode , chemistry , metallurgy , power (physics) , physics , quantum mechanics , geology , engineering , biochemistry , oceanography
Synergistic improvements in the electrical conductivity and catalytic activity for the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) are of paramount importance for rechargeable metal–air batteries. In this study, one‐nanometer‐scale ultrathin cobalt oxide (CoO x ) layers are fabricated on a conducting substrate (i.e., a metallic Co/N‐doped graphene substrate) to achieve superior bifunctional activity in both the ORR and OER and ultrahigh output power for flexible Zn–air batteries. Specifically, at the atomic scale, the ultrathin CoO x layers effectively accelerate electron conduction and provide abundant active sites. X‐ray absorption spectroscopy reveals that the metallic Co/N‐doped graphene substrate contributes to electron transfer toward the ultrathin CoO x layer, which is beneficial for the electrocatalytic process. The as‐obtained electrocatalyst exhibits ultrahigh electrochemical activity with a positive half‐wave potential of 0.896 V for ORR and a low overpotential of 370 mV at 10 mA cm −2 for OER. The flexible Zn–air battery built with this catalyst exhibits an ultrahigh specific power of 300 W g cat −1 , which is essential for portable devices. This work provides a new design pathway for electrocatalysts for high‐performance rechargeable metal–air battery systems.