Controlled micro/mesoporous carbon aerogel structure as a template for Bi2O3 nano-particles/rods to improve the performance of asymmetric supercapacitors

Abstract

Metal oxides combined with porous carbon nanostructures as the active substance in supercapacitor electrodes have been considered by many researchers. In this study, the electrochemical performance of metal oxide nanoparticles and nanorods for application in supercapacitors has been studied. Bi2O3 nanoparticles and nanorods with carbon aerogel (CA) template are combined in a nanocomposite structure via one-pot synthesis technique. Regarding the high surface area (686 m2 g−1), this nanocomposite showed a good electrochemical performance and the corresponding electrode achieved an specific capacity of 1193 F g−1 at 1 A g−1 current density in a 3-electrode system while the specific capacity of CA-Bi2O3 electrodes were 135 F g−1 and 672 F g−1, respectively at the same current density. Moreover, in the pr-Bi2O3-CA electrode, the capacity was reduced 5.3% by 6000 cycles showing cyclic stability due to fast charge transfer during the electrochemical process. A cell has been fabricated using pr-Bi2O3-CA and CNF electrodes resulting in a high performance supercapacitor with 15975 W kg−1 and 44.45 Wh kg−1 specific power and specific energy, respectively. The performance of this supercapacitor is much higher than general capacitors and close to NI-MH batteries. Red Light-Emitting Diode (LED) is also lit successfully by two supercapacitors in series. Based on the results, the suitable electrochemical efficiency of pr-Bi2O3-CA electrode approves a promising alternative for energy storage.