Hasi Rani Barai
Assistant Professor at Yeungnam University, South Korea
Title: Nano-structural design of 0D, 1D, 2D, 3D nanoparticles for energy storage devices: Supercapacitor applications
Biography
Biography: Hasi Rani Barai
Abstract
Nano-structural design for energy storage devices depends on a variety of factors like as structure and properties of the nano-materials. The recent development in nano-structural design has opened up new frontiers by creating new materials and structures for efficient energy storage. In this research, we demonstrated the annealing-free synthesis of K-doped mixed-phase TiO2 (anatase and rutile, AR) 0D nanoparticles, 1D nanowires, 2D nanosheets, and 3D nanofoams (K-TNF) on Ti foil at 150 °C and 250 °C assisted by KOH(aq.) for electrochemical supercapacitors (ESCs). The aggregated network and the average diameter of K-TNF have slightly decreased with the increase of KOH(aq.) concentrations, while the amount of K-doping, Ti3+ interstitials, and –OH functional groups was substantially increased. The TiO2 phase was entirely mixed of rutile and anatase, AR phase. All the K-TNF modified Ti electrodes (K-TNF/Ti) exhibited quasi-rectangular shaped cyclic voltammograms (CVs) in a wide potential range and the specific capacitance (Cs) for the optimal electrode with mixed AR phase TiO2 obtained. The higher Cs for the optimal K-TNF/Ti electrode can be ascribed to the synergistic effect of mixed AR phase, a high percentage of K-doping (ca.20.20%), and Ti3+ interstitials (ca.18.20 %), respectively. The directional electron transport through the 1D channel as well as the –OH functional groups on the K-TNF surface also contributes to enhancing Cs. The K-TNF/Ti electrode discovered excellent stability with the Cs retention of ca. 95% and a very small change of internal series resistance (Rs) and charge transfer resistance (Rct) at the electrode-electrolyte interface after 3000-CD cycles.