Unveiling the performance metrics for supercapacitor electrodes with adsorbed redox additives
| Autor: | Glaura G. Silva, Paulo F.R. Ortega, Rodrigo L. Lavall, Rodrigo Della Noce, Alan M. P. Sakita |
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| Rok vydání: | 2021 |
| Předmět: |
Supercapacitor
Materials science General Chemical Engineering 02 engineering and technology Glassy carbon 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences Redox 0104 chemical sciences Dielectric spectroscopy Chemical engineering Electrode Gravimetric analysis Cyclic voltammetry 0210 nano-technology |
| Zdroj: | Electrochimica Acta. 390:138803 |
| ISSN: | 0013-4686 |
| DOI: | 10.1016/j.electacta.2021.138803 |
| Popis: | In recent years, the use of supercapacitors with redox additives has been widely explored with the aim of maximizing energy density. However, the inclusion of such additives increases the complexity of the charge storage mechanisms, requiring more attention in quantifying performance parameters. Specific electrode capacities and capacitances are one of the most reported parameters and have been often overestimated or misinterpreted in relation to each other. Here, we evaluate these parameters considering the surface excess ( Γ * ) of redox additives adsorbed on electrode, which is obtained by current contribution separation from cyclic voltammetry (CV) measurements. Activated glassy carbon (AGC) electrodes in absence and presence of adsorbed methylene blue (MB) are studied by CV, chronopotentiometry and electrochemical impedance spectroscopy. The gravimetric normalization is obtained by means of Γ * and reveals specific capacity of 41.2±1.9 mAh g−1, around half of the theoretical for MB in 1e−-process. Finally, a comprehensive electrochemical discussion is done to assist the researcher community to improve performance metrics in supercapacitor electrodes in the presence of redox additives. |
| Databáze: | OpenAIRE |
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