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 capacitance 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 carrier of MnO₂, but also the Ti substrate could be used for the current collector, which alleviates the weight of the supercapacitor and provides a method for preparing supercapacitors.