Sonochemical assisted synthesis MnO2/RGO nanohybrid as effective electrode material for supercapacitor
Sonochemical assisted synthesis MnO2/RGO nanohybrid as effective electrode material for supercapacitor
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DOI：
10.1016/j.ultsonch.2017.08.013
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发表时间：
2018-01-01
影响因子：
8.4
通讯作者：
Boore-talari, Omid
中科院分区：
文献类型：
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作者：
Ghasemi, Shahram;Hosseini, Sayed Reza;Boore-talari, Omid
以溴酸钾和硫酸锰为原料，采用声化学法成功地合成了二氧化锰针状纳米结构。此外，通过静电共沉淀法制备了二氧化锰纳米颗粒与氧化石墨烯纳米片的杂化材料。调节pH值为3.5时，MnO_2和GO_2上分别产生正电荷和负电荷，相互吸引，形成共沉淀。然后将粘贴在不锈钢网上的MnO2/GO通过施加-1.1V的电压进行电化学还原，得到MnO2/RGO纳米杂化材料。用拉曼光谱、X射线衍射(XRD)、原子力显微镜(AFM)、场发射扫描电子显微镜(FE-SEM)、能谱(EDX)和热重分析(TGA)对MnO2和MnO2/RGO纳米杂化材料的结构和形貌进行了表征。用循环伏安(CV)、恒电流充放电测试和交流阻抗法(EIS)研究了MnO_2和MnO_2/RGO活性材料在0.0V~1.0V的0.5M硫酸钠水溶液中的电容行为。电化学研究表明，MnO_2/RGO在1Ag(-1)的电流密度下表现出375Fg(-1)的高比电容(C-S)和良好的循环稳定性(在200 mV S(-1)的扫描速率下500次循环后的容量保持率为93%)。研究结果为静电共沉淀法制备石墨烯/金属氧化物纳米杂化材料作为超级电容器的有效电极材料提供了良好的应用前景。
Manganese dioxide (MnO2) needle-like nanostructures are successfully synthesized by a sonochemical method from an aqueous solution of potassium bromate and manganese sulfate. Also, hybride of MnO2 nanoparticles wrapped with graphene oxide (GO) nanosheets are fabricated through an electrostatic coprecipitation procedure. With adjusting pH at 3.5, positive and negative charges are created on MnO2 and on GO, respectively which can electrostatically attract to each other and coprecipitate. Then, MnO2/GO pasted on stainless steel mesh is electrochemically reduced by applying -1.1 V to obtain MnO2/RGO nanohybrid. The structure and morphology of the MnO2 and MnO2/RGO nanohybrid are examined by Raman spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), field emission-scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDX), and thermal gravimetric analysis (TGA). The capacitive behaviors of MnO2 and MnO2/RGO active materials on stainless steel meshes are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge test and electrochemical impedance spectroscopy (EIS) by a three-electrode experimental setup in an aqueous solution of 0.5 M sodium sulfate in the potential window of 0.0-1.0 V. The electrochemical investigations reveal that MnO2/RGO exhibits high specific capacitance (C-s) of 375 F g(-1) at current density of 1 A g(-1) and good cycle stability (93% capacitance retention after 500 cycles at a scan rate of 200 mV s(-1)). The obtained results give good prospect about the application of electrostatic coprecipitation method to prepare graphene/metal oxides nanohybrids as effective electrode materials for supercapacitors.