Enhanced capacitance of TiO2 nanotubes topped with nanograss by H3PO4 soaking and hydrogenation doping. (10th March 2018)

• Record Type: Journal Article
• Authors: Zhao, Siwei; Chen, Ying; Zhao, Zhiyang; Jiang, Longfei; Zhang, Chi; Kong, Jianshou; Zhu, Xufei
• Is Part Of: Electrochimica acta. Volume 266(2018)
• Page Start: 233
• Page End: 241
• Publication Date: 2018-03-10
• Subjects: Anodic TiO2 nanotubes -- Supercapacitor -- Nanograss -- Hydrogenation -- Doping; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2018.02.037
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Anodic TiO2 nanotubes have been intensively studied for the application in supercapacitors, but the formation of nanograss is often avoided for the belief that it may retard capacitive performance. We fabricate TiO2 nanotubes topped with nanograss by H3 PO4 solution soaking and hydrogenation doping, which in fact increases the capacitance of nanotubes in a fast and convenient way. The new structure exhibits an enhanced areal capacitance by up to 67.7% and by up to 23.5% after 2000 times of cycling. The capacitance generally increases with the nanotube length and reaches the maximum with an optimal nanograss length. The electric charge during hydrogenation doping is determined to quantify the general doping effect. Compared with ordinary nanotubes, nanograss has larger contact area with electrolyte during doping. Therefore, the grass-topped structure yields more electric charge and Ti 3+ during doping, which attributes to the improved capacitance. Highlights: Nanograss topped on TiO2 nanotubes proves to increase the areal capacitance by 67.7%. H3 PO4 soaking and hydrogenation doping is a fast way to fabricate nanograss-topped nanotubes. Electric charge during doping is calculated to quantify the doping effect. The relation between capacitance and soaking time is explained.