Rahimi Seyed Abbas, Norouzi Parviz, Ganjali Mohammad Reza
Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran Tehran Iran
Biosensor Research Center, Endocrinology & Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences Tehran Iran.
RSC Adv. 2018 Jul 27;8(47):26818-26827. doi: 10.1039/c8ra04105a. eCollection 2018 Jul 24.
In this study, Co(OH)-reduced graphene oxide has been synthesized using a simple and rapid one-step cathodic electrodeposition method in a two electrode system at a constant current density on a stainless steel plate, and then characterized as a supercapacitive material on Ni foam. The composites were characterized by FT-IR, X-ray diffraction, scanning electron microscopy, and cyclic voltammetry using a galvanostatic charge/discharge test. The feeding ratios of the initial components for electrodeposition had a significant effect on the structure and electrochemical performance of the Co(OH)-reduced graphene oxide composite. The results show that the 1 : 4 (w/w) ratio of GO : CoCl·6HO was optimum and produced an intertwined composite structure with impressive supercapacitive behavior. The specific capacitance of the composite was measured to be 734 F g at a current density of 1 A g. Its rate capability was ∼78% at 20 A g and its capacitance retention was 95% after 1000 cycles of charge-discharge. Moreover, its average energy density and power density were calculated to be 60.6 W h kg and 3208 W kg, respectively. This green synthesis method enables a rapid and low-cost route for the large scale production of Co(OH)-reduced graphene oxide nanocomposite as an efficient supercapacitor material.
在本研究中，采用简单快速的一步阴极电沉积法，在两电极体系中于不锈钢板上以恒定电流密度合成了氢氧化钴还原氧化石墨烯，然后将其作为泡沫镍上的超级电容材料进行表征。通过傅里叶变换红外光谱、X射线衍射、扫描电子显微镜以及使用恒电流充放电测试的循环伏安法对复合材料进行了表征。电沉积初始组分的进料比例对氢氧化钴还原氧化石墨烯复合材料的结构和电化学性能有显著影响。结果表明，氧化石墨烯与六水合氯化钴的质量比为1∶4时最为适宜，制得的复合结构相互缠绕，具有令人印象深刻的超级电容性能。在电流密度为1 A g时，该复合材料的比电容测得为734 F g。在20 A g时其倍率性能约为78%，经过1000次充放电循环后其电容保持率为95%。此外，计算得出其平均能量密度和功率密度分别为60.6 W h kg和3208 W kg。这种绿色合成方法为大规模生产作为高效超级电容器材料的氢氧化钴还原氧化石墨烯纳米复合材料提供了一条快速且低成本的途径。
