1. Hierarchical NiCo2O4@NiCo2O4 Core/Shell Nanoflake Arrays as High-Performance Supercapacitor Materials
- Author
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X.Y. Liu, Changdong Gu, S.J. Shi, Jiangping Tu, Hong Tang, Lu Li, Yi-jun Zhang, Qin-qin Xiong, and Xiuli Wang
- Subjects
Supercapacitor ,Materials science ,Chemical engineering ,Electrode ,Shell (structure) ,General Materials Science ,Nanotechnology ,Capacitance ,Current density ,Hydrothermal circulation ,Ion ,Chemical bath deposition - Abstract
Hierarchical NiCo2O4@NiCo2O4 core/shell nanoflake arrays on nickel foam for high-performance supercapacitors are fabricated by a two-step solution-based method which involves in hydrothermal process and chemical bath deposition. Compared with the bare NiCo2O4 nanoflake arrays, the core/shell electrode displays better pseudocapacitive behaviors in 2 M KOH, which exhibits high areal specific capacitances of 1.55 F cm(-2) at 2 mA cm(-2) and 1.16 F cm(-2) at 40 mA cm(-2) before activation as well as excellent cycling stability. The specific capacitance can achieve a maximum of 2.20 F cm(-2) at a current density of 5 mA cm(-2), which can still retain 2.17 F cm(-2) (98.6% retention) after 4000 cycles. The enhanced pseudocapacitive performances are mainly attributed to its unique core/shell structure, which provides fast ion and electron transfer, a large number of active sites, and good strain accommodation.
- Published
- 2013
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