MnO_2/TiO_2复合物电极的制备及超级电容性能

采用水热法在阳极氧化的TiO_2纳米管阵列上修饰MnO_2,制备MnO_2/TiO_2复合物电极,并组装为对称超级电容器。利用FESEM、TEM、XPS和电化学工作站对样品的表面形貌、元素价态和电化学性能进行表征。结果表明:MnO_2以纳米颗粒形态均匀分布在TiO_2纳米管阵列管口和内部,充放电电流密度在1A/g下时,比电容为429.3F/g,经5 000次循环后的电容保持率为82.4%。MnO_2/TiO_2对称超级电容器在电流密度5A/g下充放电比电容为39.9F/g,经5 000次循环后的电容保持率为91.5%;功率密度400 W/kg下,能量密度为18.98 Wh/kg。阳极氧化的TiO_2纳米管阵列既可做MnO_2的载体,基底Ti又可做集流体,减轻了超级电容器的质量,为制备超级电容器提供了一种思路。

Preparation and supercapacitive performance of MnO2/TiO2 composite electrodes

The MnO2/TiO2 composite electrodes were prepared with modifying MnO2 onto the anodized TiO2 nanotube arrays by the hydrothermal method.The supercapacitor was assembled with the two symmetric MnO2/TiO2 electrodes.The surface morphology,valence of the elements and electrochemical performance of the samples were characterized by FESEM,TEM,XPS and the electrochemical workstation.The results show that the MnO2 nanoparticles are uniformly loaded onto the outer and inner surface of the TiO2 nanotube array.The specific capaci-tance is 429.3 F/g at a charge-discharge current density of 1 A/g with 82.4% of the initial capacitance after 5 000 cycles.The MnO2/TiO2 symmetrical supercapacitor exhibits the charge-discharge specific capacitance of 39.9 F/g at the current density of 5 A/g with 91.5% of the initial capacitance after 5 000 cycles and the energy density of 18.98 Wh/kg at the power density of 400 W/kg.Not only the anodized TiO2 nanotube arrays could serve as the car-rier of MnO2 ,but also the Ti substrate could be used for the current collector,which alleviates the weight of the su-percapacitor and provides a method for preparing supercapacitors.