熔盐法制备二氧化锰及其电化学性能

以高锰酸钾和醋酸锰为原料,用熔盐法在KCl-LiCl体系中合成了二氧化锰(MnO2)电极材料。用X射线衍射(XRD)对其结构进行了考察,结果表明,合成样品含α-MnO2和γ-MnO2的混合晶相。用扫描电子显微镜(SEM)对样品形貌进行了表征,照片显示样品为棒状纤维。在c〔(NH4)2SO4〕=2 mol/L电解液中采用三电极体系对样品进行循环伏安、交流阻抗和恒流充放电测试,结果显示该材料在0~1 V(SCE)的电位窗口内具有良好的矩形特征和动力学可逆性;其等效串联电阻(Rs)和电极反应电阻(Rr)分别为0.67Ω和0.72Ω;在电流密度为2 mA/cm2时,单电极放电比容量达到246.20 F/g,表现出优异的超级电容特性。

Molten Salt Synthesis and Electrochemical Properties of Manganese Dioxide

MnO2 was prepared with KMnO4 and Mn(CH3COO)2 by molten salt method in a system of KCl-LiCl then characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM).Results of XRD show that the crystal structures of the obtained sample consist of α-MnO2 and γ-MnO2.SEM images demonstrate that the sample has rod-like apparent structure.Cyclic voltammetry,AC impedance and constant current charge/discharge were carried out on the sample in three-electrode system.The results of electrochemical tests show that the sample exhibits good rectangle feature in 2 mol/L(NH4)2SO4 and kinetic reversibility in potential range of 0～1 V(SCE).Moreover,the values of Rs and Rr are 0.67 Ω and 0.72 Ω respectively.The specific discharge capacitance of the sample is 246.20 F/g at the current of 2 mA/cm2.The results indicate that the products have excellent supercapacitor properties.