Study On The Preparation And Properties Of Titanium,Manganese Composite Material By Electrochemical Method

In this thesis,Ti-Mn?Mn:3.0,7.0,10.0 wt%?alloys were prepared by a power metallurgical method.Mn-doped TiO₂ films were prepared directly by anodising Ti-Mn alloys.By changing the anodic oxidation conditions,both porous film and nanotube arrays film were obtained.Morphologies,structures,elemental valence state,manganese content,and specific surface area of the samples were investigated using a scanning electron microscope?SEM?,an X-ray diffractometer?XRD?,an X-ray photoelectron spectroscope?XPS?,an inductively coupled plasma optical emission spectrometer?ICP?,and specific surfacearea analyser?BET?,respectively.Effects of morphologies,manganese concentration of alloys and annealing temperature on the capacitive performance of the oxide films were discussed.1.TiO₂ and Mn-doped TiO₂ nanotube arrays with similar morphologies were successfully prepared.Doping manganese into TiO₂ nanotube arrays obviously enhanced their capacitive properties.When manganese content of alloy was 7.0 wt%and annealing temperature was 300°C,the areal capacitance reached up to the highest value of 1662.5?F/cm² at a current density of 5.0?A/cm².The retention of capacitance was 89.0%when the current density changed from 5.0 to 12.5 mA/cm².Moreover,the capacitance retention was 84.6%after 2000 cycles.2.TiO₂-Mn?7%?micro/nanostructure porous film was successfully prepared.When TiO₂-Mn?7%?was anodised in aqueous solution containing 30 wt%ethylene glycol at 30°C and 40 V for 3 h and annealing temperature was 300°C,the film yielded the highest areal capacitance of 2076.8 mF/cm² at a current density of 3mA/cm².Areal capacitance retention was 74.8%when the current density increases from 3 to 20 mA/cm²,and the capacitance retention was 89.3%after 5000 cycles.3.The capacitance performance of TiO₂-Mn?7%?porous film was compared to nanotube arrays film.The areal capacitance of porous film was higher than that of nanotube arrays and the cycling performance was better than that of nanotube arrays.The areal capacitance of porous film was about 326 times higher than that of nanotube arrays films at the same scan rate?5 mV/s?and the capacitance retention was higher than that of nanotube arrays after long-term cycling measurements.4.The reasons why the porous film possesses such a high areal capacitance were discussed.The enhanced capacitance properties of the porous film might be mainly ascribed to specific preparation method and unique morphology structure.The brush-like alloy substrate of the porous film would greatly improve the contact area and conductive ability between oxide layer and the metal substrate,and therefore,significantly reduce the charge transfer resistance and increase the utilisation rate of the active materials.Additionally,manganese content and specific surface area of porous film also have a certain influence on its performance.