Hierarchical SnO2 nanoclusters wrapped functionalized carbonized cotton cloth for symmetrical supercapacitor.

Abstract As an excellent free-standing carbon source, commercialized cotton cloth can be carbonized to fabricate conductive carbon cloth composed of hollow carbon microfibers. In view of the hydrophobicity of carbon cloth, a functionalized carbonized cotton cloth (FCC) is prepared by acidification treatment, and acted as a flexible substrate to grow hierarchical SnO 2 nanoclusters by a solvothermal reaction and calcination process. In this SnO 2 wrapped FCC (FCC@SnO 2) composite, the oxygen-containing groups in carbon microfibers provide numerous anchoring sites for growing SnO 2 nanoparticles, meanwhile, the carbon microfibers provide conductive channels for the fast transfer of electrons and ions. The SnO 2 nanoclusters effectively contribute their pseudocapacitance. As free-standing electrodes in a symmetrical two-electrode supercapacitor, the FCC@SnO 2 composite exhibits a higher capacitance of 197.7 F g−1 or 1265.3 mF cm−2 at 1 A g−1, much higher than that of FCC (100.3 F g−1 or 411.2 mF cm−2); furthermore, its capacitance remains 95.5% after cycling for 5000 cycles at 15 A g−1. The FCC@SnO 2 composite is easier preparation and low cost, which can be utilized as self-supporting flexible electrodes for high performance supercapacitors. Graphical abstract Image 1 Highlights • Acidified carbonized cotton cloth is acted as a freestanding flexible substrate. • Hierarchical SnO 2 nanoclusters are wrapping on the surface of carbon microfibers. • FCC@SnO 2 exhibits a capacitance of 197.7 F g−1 or 1265.3 mF cm−2 at 1 A g−1. • Its capacitance retains 95.5% after cycling for 5000 cycles at 15 A g−1. [ABSTRACT FROM AUTHOR]