writer：Y. P. Huang, Y. E. Miao, H. Y. Lu, T. X. Liu*
keywords：ZnCo2O4@NiCo2O4 Core-Sheath Nanowires, Bifunctionality, Supercapacitors, Oxygen Reduction Reaction.
source：期刊
specific source：Chem. Eur. J., 2015, 21(28), 10100-10108.
Issue time：2015年
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 ZnCo₂O₄@NiCo₂O₄ core–sheath nanowires synthesized through facile electrospinning combined with a simple co-precipitation method is proposed. The obtained core–sheath nanostructures consisting of mesoporous ZnCo₂O₄ nanowires as the core and uniformly distributed ultrathin NiCo₂O₄ 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 ZnCo₂O₄ nanowires or NiCo₂O₄ nanosheets, the hierarchical ZnCo₂O₄@NiCo₂O₄ 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 ZnCo₂O₄@NiCo₂O₄ 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.