Supercapacitive performance of hydrogenated TiO2 nanotube arrays decorated with nickel oxide nanoparticles

Abstract

Highly ordered self-organized TiO₂ nanotube arrays (TNTAs) could not only be used as current collectors, but also adopted as highly ion-accessible and charge transfer-channels for the construction of supercapacitors. In this paper, hydrogenated TNTAs were obtained and then nickel oxide (NiO_x) nanoparticles were successfully deposited onto the inner surface and interface of HTNTAs through a cyclic voltammetry electrochemical deposition process (NiO_x/HTNTAs). The FESEM images of the samples showed that the diameter of the NiO_x nanoparticles ranged from 7 to 60 nm. The as-fabricated NiO_x/HTNTAs exhibited an obviously pseudocapacitive performance with a specific capacitance of 689.28 F g⁻¹ at a current density of 1.5 A g⁻¹ and 91.9% of the initial capacitance remaining after 5000 charge/discharge cycles at a current density of 3 A g⁻¹ in 1 M KOH. This work reveals a feasible and green method for the fabrication of TNTAs modified with electroactive metal oxide nanoparticles as functional electrode materials for supercapacitors.