水热合成时间对纳米MnO_2超电容性能的影响  

Influence of hydrothermal synthesis time on pseudocapacitive properties of nano-sized MnO_2 by hydrothermal method

作　　者：王爱萍[1] 周爱华[2] WANG Aiping;ZHOU Aihua(School of Materials Science and Engineering, Ocean University of China, Qingdao 266100, China;Qingdao Technical College, Qingdao 266555, China)

机构地区：[1]中国海洋大学材料科学与工程学院,山东青岛266100 [2]青岛职业技术学院,山东青岛266555

出　　处：《功能材料》2017年第12期12005-12010,共6页Journal of Functional Materials

基　　金：国家青年科学基金资助项目(51202229)

摘　　要：以KMnO_4和MnSO_4·H_2O为原料,利用水热合成纳米MnO_2。采用X射线衍射(XRD)、场发射扫描电镜(SEM)、比表面积测试(BET)、循环伏安(CV)、恒流充放电以及交流阻抗(EIS)等方法研究水热合成时间对产物结构以及电化学性能的影响。结果表明水热合成为棒状纳米级α-MnO_2,随着水热合成时间增加,结晶度增加;水热合成纳米α-MnO_2在1 mol/L Na_2SO_4水溶液中具有良好的电化学电容性能,其中水热合成24 h制备棒状纳米MnO_2具有较高比电容,其真实电容量达到189 F/g;交流阻抗测试表明水热合成24 h制备的纳米MnO_2样品法拉第电荷传递能力和离子在电解液与活性材料界面的扩散能力得到提高,具有良好的电化学性能。Rod likeα-MnO2nanostructures were prepared via hydrothermal process by using KMnO4and MnSO4·H2O for different time.The effects of hydrothermal reaction time on physical and electrochemical properties of obtained MnO2were studied by using X-ray diffraction(XRD),scanning electron microscope(SEM),specific surface measurement(BET),cyclic voltammetry(CV),galvanostatic charge discharge method and electrochemical impedance spectroscopy(EIS).Results indicated that the crystallinity degree of MnO2increased with the increasing of synthesis time.Theα-MnO2nanorods prepared by hydrothermal synthesis method showed fine capacitive behavior in1mol/L Na2SO4solution.With the increasing of synthesis time,the specific capacitance increased to a maximum value and then decreased.The composite prepared by hydrothermal conditions for24h has the highest specific capacitance of189F/g.The EIS tests showed that the MnO2sample prepared via hydrothermal process for24h promoted the ability of faradic charger transfer and the diffusion of ion on the interface between the active material particles and electrolyte,showing an excellent electrochemical performance and high specific capacitance.

关 键 词：纳米MNO2 水热法 纳米棒 电化学电容器 

分 类 号：TM53[电气工程—电器] O614.7[理学—无机化学]