Supercapacitor Performance Of MnO₂/TiO₂ Nanotube Arrays Composite Electrode Materials

Highly ordered TiO2 nanotube arrays modified by other materials with enhanced conductivity and capacitance have been considered to be promising anode materials for supercapacitors. In this thesis, all works are listed as follows:(1) The MnO2/TiO2 nanotube arrays were synthesized by sequential chemical bath deposition method. The sample-Ⅲ shows a remarkable gravimetric capacitance of 258.9 F/g at a current density of 1 A/g;(2) To enhance the conductivity of TiO2 nanotube arrays, the cathodic polarization treatment and calcination under an Ar atmosphere were used respectively. The areal capacitance of TiO2 nanotube arrays calcinated under air is 0.24 mF/cm2 at a current density of 1 mA/cm . The areal capacitance can be enhanced to 7.45 mF/cm2 at a current density of 1 mA/cm2 after cathodic polarization treatment. While the areal capacitancewill be improved to 9.36 mF/cm2 at a current density of 1 mA/cm2 after calcination under an Ar atmosphere;(3) The MnO2/carbon@TiO2 nanotube arrays can be synthesized by sequential chemical bath deposition method and show a gravimetric capacitance of 439 F/g at a current density of 1 A/g;(4) The MnO2/carbon@TiO2 nanotube arrays were synthesized by hydrothermalmethod and achieved a gravimetric capacitance of 521.4 F/g at a current density of 2 A/g.Furthermore sample-Ⅲ exhibits good long-term capacitive stability with the capacitance retention about 88.6% after 2000 cycles at a current density of 5 A/g.