Supercapacitive performance of electrochemically doped TiO2 nanotube arrays decorated with Cu2O nanoparticles

Abstract

Highly ordered TiO₂ nanotube arrays (TNAs) with enhanced electronic conductivity treated by introducing oxygen vacancies have been considered to be a promising electrode material for supercapacitors. In this work, we fabricated electrochemically doped TiO₂ nanotube arrays (ED-TNAs) through a facile cyclic voltammetry method, and then deposited the uniformly dispersed Cu₂O nanoparticles onto ED-TNAs to synthesise a high performance electrode for a supercapacitor. The ED-TNAs electrode exhibited a high specific capacitance of 5.42 mF cm⁻² at a scan rate of 10 mV s⁻¹, which was about 59 times higher than for the pristine TNAs electrode. Moreover, the ED-TNAs were demonstrated to be an appropriate support for Cu₂O nanoparticles. The highest specific capacitance of the Cu₂O/ED-TNAs electrode could reach 198.7 F g⁻¹ at the current density of 0.2 A g⁻¹, and approximately 88.7% of the initial capacitance was retained after 5000 cycles of galvanostatic charge–discharge.