FACILE SYNTHESIS AND UNUSUAL ELECTROCHEMICAL CAPACITANCE OF Ni-DOPED TITANATE NANOTUBES

Abstract

In this paper, we developed an intriguing ion-exchange reaction to synthesize Ni -doped titanate nanotubes ( Ni - Ti -NTs), and utilized the sample as an appealing pseudocapacitive electrode for electrochemical capacitors (ECs). The energy storage mechanism of the resulting Ni - Ti -NTs electrode in alkaline KOH aqueous electrolyte was further tentatively proposed. Compared with the pristine titanate nanotubes ( Ti -NTs), Ni - Ti -NTs with rich porous channels possessed much better electronic conductivity and larger specific surface area, rendering the electrons and OH − ions easily contact the Ni species uniformly distributed on their surfaces for efficient energy storage at high rates. Remarkably, the SC of the Ni - Ti -NTs electrode increased with further cycling, and even reached a SC of 278 F g−1 at a current density of 2 A g−1 after 7500 charge–discharge cycles without relaxation. The prominent electrochemical performance demonstrated that the Ni - Ti -NTs would be a promising candidate and/or even excellent support for other electroactive materials for advanced ECs application.