Hydrothermal synthesis of single-walled carbon nanotubes/TiO<inf>2</inf> for quasi-solid-state composite-type symmetric hybrid supercapacitors

Development of long cycle life hybrid supercapacitors without compromising with specific energy is a real challenge because of volume expansion, which causes electrode material degradation in due course of time. Herein, an advanced electrode material based on high mechanically as well chemically stable titanium dioxide (TiO2) nanoparticles and single-walled carbon nanotubes (SWCNTs) i.e. (SWCNTs/TiO2 nanocomposite), is developed for composite-type hybrid supercapacitors. A simple and cost-effective hydrothermal technique is utilized for preparing SWCNTs/TiO2 nanocomposite. Meanwhile, a quasi-solid-state composite-type symmetric hybrid supercapacitor based on SWCNTs/TiO2 nanocomposite as electrodes and PVA/H2SO4 as gel electrolyte with voltage window 1 V is fabricated. As a result, high capacitance of 144 F g−1, specific energy of 20 Wh kg−1 and remarkable cycling life of 95 % upto 50 k cycles are delivered. This work indicates that the hybrid electrochemical behaviour of SWCNTs/TiO2 nanocomposite improves the overall supercapacitive performance and offers a promising route to develop the high performance hybrid supercapacitor.