Sulfide-enhanced electrochemical capacitance of cobalt hydroxide on nanofibered parent substrate

摘要: Two approaches—substrate nanostructuring and incorporation of sulfide—were studied with the aim to increase electrochemical capacitance cobalt (hydro)oxide. A fiber structure was deposited electrochemically fibers in order tens nanometers thickness hundreds length. Cobalt hydroxide film formed on nanostructured substrate by anodic polarization an alkaline solution. The formation its have been cyclic voltammetry conjunction quartz crystal microbalance (EQCM). An irreversible behavior typical first cycle; it turned gradually a reversible one during subsequent cycling. EQCM measurements indicated exponential electrode mass growth cycle, transition quasipassive state. redox transitions Co(II) → Co(III) Co(IV), which determine pseudocapacitance, did not cause remarkable change. nanofiber sample found up five times higher when compared that conventional (abraded surface). Specifics “per 1 g” evaluation performance is discussed. Measurements showed about 10% entire took part capacitive process. value determined per g active Co(OH)2 agreement limiting predicted Faraday’s law (2,421 F g−1) sulfide-enhanced system 18% CoS exhibited three sulfide-free counterpart. shows promise for practical applications due low cost technical simplicity.