纳米花
材料科学
超级电容器
电化学
电容
电极
循环伏安法
化学工程
介电谱
分析化学(期刊)
纳米技术
纳米结构
化学
色谱法
物理化学
工程类
作者
Gomaa A. M. Ali,Mashitah M. Yusoff,E.R. Shaaban,Kwok Feng Chong
标识
DOI:10.1016/j.ceramint.2017.03.195
摘要
MnO2 nanoflower is prepared by electrochemical conversion of Mn3O4 obtained by heat treatment of spent zinc‒carbon batteries cathode powder. The heat treated and converted powders were characterized by TGA, XRD, FTIR, FESEM and TEM techniques. XRD analyses show formation of Mn3O4 and MnO2 phases for the heat treated and converted powders, respectively. FESEM images indicate the formation of porous nanoflower structure of MnO2, while, condensed aggregated particles are obtained for Mn3O4. The energy band gap of MnO2 is obtained from UV‒Vis spectra to be 2.4 eV. The electrochemical properties are investigated using cyclic voltammetry, galvanostatic charge‒discharge and electrochemical impedance techniques using three-electrode system. The specific capacitance of MnO2 nanoflower (309 F g−1 at 0.1 A g−1) is around six times higher than those obtained from the heat treated one (54 F g−1 at 0.1 A g−1). Moreover, it has high capacitance retention up to 93% over 1650 cycles. Impedance spectra of MnO2 nanoflower show very small resistances and high electrochemical active surface area (340 m2 g−1). The present work demonstrates a novel electrochemical approach to recycle spent zinc-carbon batteries into high value supercapacitor electrode.
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