MnO_2纳米空心球的制备及其电化学性能

Synthesis and electrochemical properties of MnO_2 hollow nanospheres

采用水热法通过添加Ce离子制备了Mn O2纳米空心球电极材料。Ce离子对Mn O2的形貌和结晶程度有很大的影响,添加Ce离子后生成由纳米棒组成的中空球,中空球比表面积(BET)达到315.2 m2·g-1。MnO2电极电化学测试结果表明:当铈锰摩尔比为0.2时电极材料具有较好的电化学性能,其比电容达到178.6 F·g-1,与未加Ce离子相比其比电容提高了2.6倍,而且经过1000次循环稳定性测试后比电容仍保留了90.5%。这些结果表明添加Ce离子有利于形成中空结构,并提高了Mn O2电极的比电容。

Electrode material of MnO2 hollow nanosphere was synthesized via a simple hydrothermal process in the presence of Ce ion. Ce ion played a crucial role in controlling the morphology and crystalline structure of MnO2. The hollow nanosphere consisted of nanorods, and Brunauer-Emmet-Teller （BET） specific surface area of the hollow nanosphere was 315.2 m2·g^-1. Electrochemical behavior of MnO2 electrode material was measured by cyclic voltammetry and galvanostatic charge-discharge. Better electrochemical properties of MnO2 electrode could be obtained when mole ratio of Ce to Mn was 0.2, and specific capacitance of as-prepared MnO2 electrode was 178.6 F·g^-1, 2.6 times higher than MnO2 electrode without Ce ions. Moreover, MnO2 electrode exhibited remarkable cyclability, and specific capacitance retained 90.5%even after 1000 cycles. Ce ion was favorable for forming a hollow structure, and improved specific capacitance of MnO2 electrode.