Zhang, Xiaojun and Shi, Wenhui and Zhu, Jixin and Zhao, Weiyun and Ma, Jan and Mhaisalkar, Subodh and Maria, Tuti Lim and Yang, Yanhui and Zhang, Hua and Hng, Huey Hoon and Yan, Qingyu (2010) Synthesis of porous NiO nanocrystals with controllable surface area and their application as supercapacitor electrodes. Nano Research, 3 (9). pp. 643-652.
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We report a facile way to grow various porous NiO nanostructures including nanoslices, nanoplates, and nanocolumns, which show a structure-dependence in their specific charge capacitances. The formation of controllable porosity is due to the dehydration and re-crystallization of β-Ni(OH)2 nanoplates synthesized by a hydrothermal process. Thermogravimetric analysis shows that the decomposition temperature of the β-Ni(OH)2 nanostructures is related to their morphology. In electrochemical tests, the porous NiO nanostructures show stable cycling performance with retention of specific capacitance over 1000 cycles. Interestingly, the formation of nanocolumns by the stacking of β-Ni(OH)2 nanoslices/plates favors the creation of small pores in the NiO nanocrystals obtained after annealing, and the surface area is over five times larger than that of NiO nanoslices and nanoplates. Consequently, the specific capacitance of the porous NiO nanocolumns (390 F/g) is significantly higher than that of the nanoslices (176 F/g) or nanoplates (285 F/g) at a discharge current of 5 A/g. This approach provides a clear illustration of the process–structure–property relationship in nanocrystal synthesis and potentially offers strategies to enhance the performance of supercapacitor electrodes.
|Subjects:||Material Science > Nanostructured materials|
|Deposited On:||24 Sep 2010 12:27|
|Last Modified:||24 Sep 2010 12:27|
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