TiO2 crystalline structure and electrochemical performance in two-ply yarn CNT/TiO2 asymmetric supercapacitors

• Published in: Journal of materials science 2017-07, Vol.52 (13), p.7733-7743
• Main Authors: Li, Ting, Wu, Yunlong, Wang, Qiufan, Zhang, Daohong, Zhang, Aiqing, Miao, Menghe
• Format: Article
• Language: English
• Subjects: Anatase; Annealing; Asymmetry; Carbon nanotubes; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crystal structure; Crystallinity; Crystallography and Scattering Methods; Electrochemical analysis; Energy Materials; Energy storage; Filaments; Flux density; Materials Science; Maximum power density; Polymer Sciences; Rutile; Solid Mechanics; Supercapacitors; Surface layers; Textiles; Titanium; Titanium dioxide; Yarn; Yarns
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-017-1033-6

Solid-state flexible energy storage devices play a crucial role in the development of wearable electronic textiles. In this study, we fabricated flexible asymmetric two-ply yarn supercapacitors from carbon nanotube yarns and surface-oxidized titanium filament. The crystalline structure of the TiO 2 surface layer can be adjusted to amorphous, anatase and rutile states by altering the annealing temperature. The titanium filament with a rutile TiO 2 surface layer produced at high annealing temperature showed far superior electrochemical performance over the filaments with amorphous and anatase TiO 2 surface layers. The as-prepared asymmetric two-ply yarn supercapacitors in aqueous gel electrolyte can achieve a durable operating voltage up to 1.4 V, with a maximum energy density of 11.7 Wh kg −1 and a maximum power density of 2060 W kg −1 . The asymmetric two-ply yarn supercapacitors exhibited excellent flexibility and cycling stability over 1200 cycles at straight, twisted and bent states.