One-step synthesis of free-standing α-Ni(OH)2 nanosheets on reduced graphene oxide for high-performance supercapacitors
One-step synthesis of free-standing α-Ni(OH)2 nanosheets on reduced graphene oxide for high-performance supercapacitors
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DOI：
10.1088/0957-4484/25/43/435403
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发表时间：
2014-10-31
期刊：
影响因子：
3.5
通讯作者：
Ding, Shujiang
中科院分区：
文献类型：
--
作者：
Dong, Bitao;Zhou, Han;Ding, Shujiang
在这项工作中，通过环境友好的一步溶液法成功地开发了还原氧化石墨烯（rGO）负载的α-Ni（OH）（2）纳米片（表示为α-Ni（OH）（2）@rGO NS）的分级混合结构。通过扫描电子显微镜、透射电子显微镜、x射线衍射、拉曼光谱、x射线光电子能谱和Brunauer-Emmett-Teller进一步表征所得的α-Ni（OH）（2）@rGO NS产物。在rGO衬底的两侧垂直地涂覆厚度约为6 nm的α-Ni（OH）（2）纳米片。当作为超级电容器的电极进行评估时，与自聚集的α-Ni（OH）（2）粉末相比，混合α-Ni（OH）（2）@rGO NS表现出优异的超级电容器性能和循环稳定性。即使在2000次循环后，混合电极在5A g（-1）的电流密度下仍然可以提供1300 F g（-1）的比电容，对应于初始循环的容量没有损失。这种优异的电化学性能应归功于α-Ni（OH）（2）的层状、自支撑和分级纳米片，其不仅促进有效的电荷传输和促进电解质扩散，而且有效地防止电活性材料在充放电过程中的聚集。
In this work, a hierarchical hybrid structure of reduced graphene oxide (rGO) supported ultrathin alpha-Ni(OH)(2) nanosheets (denoted as alpha-Ni(OH)(2)@rGO NSs) has been developed successfully via an environmentally friendly one-step solution method. The resulting product of alpha-Ni (OH)(2)@rGO NSs was further characterized by scanning electron microscope, transmission electron microscope, x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller. The ultrathin alpha-Ni(OH)(2) nanosheets of around 6 nm in thickness are uprightly coated on the double sides of rGO substrate. When evaluated as electrodes for supercapacitors, the hybrid alpha-Ni(OH)(2)@rGO NSs demonstrate excellent supercapacitor performance and cycling stability, compared with the self-aggregated alpha-Ni(OH)(2) powder. Even after 2000 cycles, the hybrid electrodes still can deliver a specific capacitance of 1300 F g(-1) at the current density of 5 A g(-1), corresponding to no capacity loss of the initial cycle. Such excellent electrochemical performance should be attributed to the ultrathin, free-standing, and hierarchical nanosheets of alpha-Ni(OH)(2), which not only promote efficient charge transport and facilitate the electrolyte diffusion, but also prevent aggregation of electro-active materials effectively during the charge-discharge process.