Ultrathin Nickel Hydroxide and Oxide Nanosheets: Synthesis, Characterizations and Excellent Supercapacitor Performances

• Published in: Scientific reports Vol. 4; no. 1; p. 5787
• Main Authors: Zhu, Youqi, Cao, Chuanbao, Tao, Shi, Chu, Wangsheng, Wu, Ziyu, Li, Yadong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29-08-2014; Nature Publishing Group
• Subjects: 639/301/299/161; 639/638/298/917; Atmospheric conditions; Capacitance; conference-proceeding; Electrochemistry; Energy storage; Graphene; Heat; Heat treatment; Humanities and Social Sciences; Low temperature; Morphology; multidisciplinary; Nanocrystals; Nanomaterials; Nickel; Science; Temperature effects
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep05787

High-quality ultrathin two-dimensional nanosheets of α-Ni(OH)
2
are synthesized at large scale via microwave-assisted liquid-phase growth under low-temperature atmospheric conditions. After heat treatment, non-layered NiO nanosheets are obtained while maintaining their original frame structure. The well-defined and freestanding nanosheets exhibit a micron-sized planar area and ultrathin thickness (<2 nm), suggesting an ultrahigh surface atom ratio with unique surface and electronic structure. The ultrathin 2D nanostructure can make most atoms exposed outside with high activity thus facilitate the surface-dependent electrochemical reaction processes. The ultrathin α-Ni(OH)
2
and NiO nanosheets exhibit enhanced supercapacitor performances. Particularly, the α-Ni(OH)
2
nanosheets exhibit a maximum specific capacitance of 4172.5 F g
−1
at a current density of 1 A g
−1
. Even at higher rate of 16 A g
−1
, the specific capacitance is still maintained at 2680 F g
−1
with 98.5% retention after 2000 cycles. Even more important, we develop a facile and scalable method to produce high-quality ultrathin transition metal hydroxide and oxide nanosheets and make a possibility in commercial applications.