Systematically controlled synthesis of rGO/nano-MnOx materials for supercapacitors

Publication date: Available online 10 December 2019Source: Progress in Natural Science: Materials InternationalAuthor(s): Xiaoyu Zhao, Haocun Yang, Yongdan Hou, Lemuel Gbologah, Liang Zhu, Yanfei WangAbstractThe effects of hydrothermal production conditions on crystal forms, morphology and electrochemical performance of in situ reduced graphene oxide/manganese oxides (rGO/MnOx) hybrid electrode materials were studied. The XRD/SEM results show that the ratio of precursors, reaction temperature and type of solvent significantly affected the crystal form obtained and nano-structure of MnOx. Varied precursor ratios of KMnO4:GO (5:1, 7:1, 9:1 and 11:1) yielded the hybrids of rGO/Mn7O135H2O, rGO/β-MnO2, rGO/Mn.98O2, and rGO/K0.27MnO2(H2O)0.54, respectively, having corresponding nano structures of nano-sheets composed petal-like shape, petal-like shape based nano-wire clusters, petal-like shape with backwardly arched top and bigger mesoporous petal-like nano structures. Hybrid prepared precursor with the ratio of 5:1 exhibited the highest specific capacitance of 320 F/g at 0.2 A/g and the smallest diffusion impedance. However, hybrid prepared precursor with the ratio of 7:1 presented the lowest electron transfer impedance. Varying hydrothermal treatment temperatures (140, 160 and 200 °C) yielded hybrids: rGO/MnO(OH), rGO/Mn0.91O1,82(H2O)0.18, and rGO/Mn7O135H2O, respectively. The nano structures of the hybrids were nano-sheets having petal-like mesoporous structure, but having...
Source: Progress in Natural Science: Materials International - Category: Materials Science Source Type: research