Preparation and properties of MnO2–TiO2 nanotube array composite electrodes using titanium foam as the current collector

Abstract

MnO2–TiO2 nanotube array composite electrodes were prepared through depositing MnO2 onto TiO2 nanotube arrays obtained by anodization of the titanium foam and the effect of morphologies of TiO2 nanotube arrays on the performance of the electrode was investigated. Results show that the wall thickness, the tube diameter and the tightness among the nanotubes affected the performance of composite electrodes. The areal, quality and volume capacitance value of the optimized sample reached up to 436.2 mF/cm2, 1470.8 mF/g and 5452.5 mF/cm3, respectively, at a current density of 0.1 mA/cm2, which were significantly higher than those of the MnO2–TiO2 nanotube array composite electrodes using planar titanium foil as the current collector. The capacitance retention was 85.7% after 3000 cycles. In addition, the influences of the cations (Li+, Na+, K+, NH4+) and anions (Cl−, Br−, I−, CH3COO−) in the testing electrolytes on the capacitance properties were also studied in detail.