Fish bladder-based activated porous carbon/co3o4/tio2 composite electrodes for supercapacitors

Abstract

Supercapacitors as energy storage devices depend on electrode materials, electrolyte and conductive additives. In relation to the above, this master’s dissertation specifically provides a scientific understanding and knowledge to the society on the use of fish bladder derived porous carbon for cobalt oxide/titanium dioxide/activated carbon (Co3O4/TiO2/Ac) composite as electrode materials for supercapacitor applications. Fish bladder was used as a carbon source for the composite after carbonization and chemical activation. Composites of Co3O4/TiO2/Ac, Co3O4/Ac, and TiO2/Ac were later synthesized using simple impregnation method followed by heat treatment and thereafter in-depth investigation on the active material was carried out through material characterization and electrochemical testing. X-ray diffraction and scanning electron microscopy (SEM) revealed that Co3O4 and TiO2 nano phases were well embedded over carbon matrices. Fourier transfer infra-red (FT-IR) measurements showed that the active material had oxygen containing functional groups. Cyclic voltammetry curves demonstrated that specific capacitance of the active material was 946 Fg -1 for Co3O4/TiO2/Ac as compared to Co3O4/Ac, TiO2/Ac, and Ac with specific capacitances of 845 F g-1 , 340 F g -1 , and 308 F g -1 , respectively at a scan rate of 5 mVs -1 . Impedance spectroscopy revealed good capacitive behavior with a series resistance of 0.5 Ω, 0.52 Ω, 0.6 Ω, and 1.1 Ω for Ac, Co3O4/Ac, Co3O4/TiO2/Ac, and TiO2/Ac, respectively. Excellent electrochemical performances observed for the Co3O4/TiO2/Ac electrode was a result of individual contribution of different characteristics of the binary metal oxides such as improved electric conductivity and wettability of the composites associated with porous carbon and TiO2.