通过水热法制备了未掺杂α-MnO2和Al掺杂α-MnO2,对产物的形貌、结构和电化学性能进行了研究.扫描电镜(SEM)和高分辨透射电镜(HRTEM)观察表明制备产物呈纳米管形态.紫外-可见光谱分析计算了产物的能带间隙：随着Al的掺杂,α-MnO2的能带间隙值降低.以未掺杂α-MnO2与Al掺杂α-MnO2作为电极材料,通过循环伏安(CV)和恒流充放电测试电极的超级电容器性能.在50 mA∙g-1电流密度下,未掺杂α-MnO2与Al掺杂α-MnO2电极的比电容分别达到了204.8和228.8 F∙g-1.电化学阻抗谱(EIS)分析表明Al的掺杂降低了α-MnO2在电解液中的阻抗,有利于提高其电化学比电容.增强的比电容及在1000个循环后仍具有良好的容量保持率,使Al掺杂α-MnO2在超级电容器中具有较好的应用前景.%α-MnO2 and Al-dopedα-MnO2 were synthesized via a hydrothermal method. The morphologies, structures, and electrochemical performances of as-synthesized un-doped and dopedα-MnO2 were studied. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) show that these un-doped and dopedα-MnO2 are nanotube shaped. The band gaps ofα-MnO2 are investigated by ultraviolet-visible absorption spectroscopy, which indicates that the band gap ofα-MnO2 decreases upon Al doping. The electrochemical performances of un-doped and doped α-MnO2 as electrode materials for supercapacitors were measured by cyclic voltammetry (CV) and galvanostatical charge/discharge tests. The specific capacitances of un-doped and Al-dopedα-MnO2 respectively reach 204.8 and 228.8 F∙g-1 under a current density of 50 mA∙g-1. It was discovered that the electrochemical impedance of Al-dopedα-MnO2 was decreased by Al doping analyzed using electrochemical impedance spectra (EIS), which provides a beneficial increase to its electrochemical specific capacitance. Enhanced specific capacitance and preferable cycling stability (up to 1000 cycles) for Al-dopedα-MnO2 mean that these systems are favorable prospects for application in supercapacitors.
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