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Hierarchical Core–Shell Nickel Cobaltite Chestnut‐like Structures as Bifunctional Electrocatalyst for Rechargeable Metal–Air Batteries
Author(s) -
Lee Dong Un,
Park Moon Gyu,
Cano Zachary Paul,
Ahn Wook,
Chen Zhongwei
Publication year - 2018
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201701832
Subject(s) - cobaltite , electrocatalyst , bifunctional , oxygen evolution , catalysis , nickel , chemical engineering , materials science , inorganic chemistry , electrochemistry , chemistry , spinel , electrode , metallurgy , organic chemistry , engineering
Nano‐engineered hierarchical core–shell nickel cobaltite chestnut‐like structures were successfully synthesized as a bifunctionally active electrocatalyst for rechargeable metal–air battery applications. Both the morphology and composition of the catalyst were optimized by a facile hydrothermal reaction, resulting in a 10 h reacted sample demonstrating significantly enhanced activity toward both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in 0.1 m KOH. Specifically, the catalyst demonstrated −0.28 and 0.60 V versus SCE (saturated calomel electrode) at the ORR half‐wave potential and an OER current density of 10 mA cm −2 , respectively. The resulting ORR/OER potential difference of 0.90 V was the smallest compared to the catalysts synthesized using 2, 6, and 12 h of hydrothermal reaction time. The excellent bifunctional activity of the catalyst is attributed to the nanoscale porous morphology and the spinel nickel cobaltite composition, which improved the active site exposure and transport of reactants and charges during the oxygen reactions.