Preparation and capacitance properties of Mn-doped TiO2 nanotube arrays by anodisation of Ti–Mn alloy

• Mn-doped TiO2 nanotube arrays film was prepared.
• The film displayed outstanding electrochemical performance for supercapacitor.
• The film was prepared by a convenient anodisation process.

Ti–Mn (Mn: 3.0, 7.0, 10.0 wt%) alloys were prepared by a power metallurgical method. Mn-doped TiO2 nanotube arrays have been achieved directly by anodising the Ti–Mn alloys. Morphologies, crystal structure, chemical composition, supercapacitor performances of samples were characterised by scanning electron microscopy, X-ray diffraction, inductively coupled plasma optical emission spectrometry, and electrochemical analysis, respectively. The effects of manganese content, scan rate, current density, and annealing temperature on the capacitive properties were studied. Results show that doping Mn into TiO2 nanotube arrays obviously enhanced their capacitive properties. The nanotube arrays prepared from Ti–Mn alloy (Mn: 7.0 wt%) exhibited the best capacitive performance and after annealed at 300 °C, the areal capacitance reached up to 1662.5 μF/cm2 at a current density of 5.0 μA/cm2. The retention of capacitance was 89.0% when the current density changed from 5.0 to 12.5 μA/cm2 and capacitance retention was 84.6% after 2000 cycles. The factors that contributed to the superior areal capacitance of the film have also been discussed.