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Hierarchical ZnCo 2 O 4 @NiCo 2 O 4 Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction
Author(s) -
Huang Yunpeng,
Miao YueE.,
Lu Hengyi,
Liu Tianxi
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201500924
Subject(s) - nanowire , supercapacitor , mesoporous material , materials science , catalysis , nanotechnology , electrospinning , bifunctional , electrochemistry , chemical engineering , capacitance , electrode , nanofiber , chemistry , composite material , biochemistry , polymer , engineering
Increasing energy demands and worsening environmental issues have stimulated intense research on alternative energy storage and conversion systems including supercapacitors and fuel cells. Here, a rationally designed hierarchical structure of ZnCo 2 O 4 @NiCo 2 O 4 core–sheath nanowires synthesized through facile electrospinning combined with a simple co‐precipitation method is proposed. The obtained core–sheath nanostructures consisting of mesoporous ZnCo 2 O 4 nanowires as the core and uniformly distributed ultrathin NiCo 2 O 4 nanosheets as the sheath, exhibit excellent electrochemical activity as bifunctional materials for supercapacitor electrodes and oxygen reduction reaction (ORR) catalysts. Compared with the single component of either ZnCo 2 O 4 nanowires or NiCo 2 O 4 nanosheets, the hierarchical ZnCo 2 O 4 @NiCo 2 O 4 core–sheath nanowires demonstrate higher specific capacitance of 1476 F g −1 (1 A g −1 ) and better rate capability of 942 F g −1 (20 A g −1 ), while maintaining 98.9 % capacity after 2000 cycles at 10 A g −1 . Meanwhile, the ZnCo 2 O 4 @NiCo 2 O 4 core–sheath nanowires reveal comparable catalytic activity but superior stability and methanol tolerance over Pt/C as ORR catalyst. The impressive performance may originate from the unique hierarchical core–sheath structures that greatly facilitate enhanced reactivity, and faster ion and electron transfer.