Understanding the rate performance of microporous carbons in aqueous electrolytes
| Autor: | Maria Angeles Lillo-Rodenas, I. Aldama, Mirko Kunowsky, Joaquín Ibáñez, José M. Rojo |
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| Přispěvatelé: | Universidad de Alicante. Departamento de Química Inorgánica, Universidad de Alicante. Instituto Universitario de Materiales, Materiales Carbonosos y Medio Ambiente, Ministerio de Ciencia e Innovación (España) |
| Rok vydání: | 2020 |
| Předmět: |
Rate performance
Microporous carbon monoliths Materials science General Chemical Engineering KOH electrolyte 02 engineering and technology Electrolyte 010402 general chemistry 01 natural sciences Capacitance Capacitance retention Electrochemistry Ionic conductivity Monolith Porosity Supercapacitor H2SO4 electrolyte Química Inorgánica geography geography.geographical_feature_category Microporous material 021001 nanoscience & nanotechnology 0104 chemical sciences Chemical engineering 0210 nano-technology Mesoporous material |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0013-4686 |
| Popis: | Variation of specific capacitance versus current density is studied for microporous carbons. Although literature states that capacitance retention is higher for macro/mesoporous than for microporous carbons, the results reported here show that high capacitance retention can be reached for microporous carbons in combination with aqueous electrolytes (2M HSO, 1M KOH and 6M KOH). Six carbon monoliths are studied; three pristine ones and those three heat-treated, so as to reduce their content of surface oxygen groups and develops porosity. The capacitance retention is analyzed based on five parameters: electronic conductivity, surface chemistry and porosity of the monoliths, ionic conductivity and type of electrolyte. The capacitance retention is higher for the monoliths working as negative (HO and K) electrodes than as positive (HSO and OH) ones, being these results of interest for the use of carbon monoliths in asymmetric and hybrid supercapacitors. The highest capacitance retention is obtained by combining (i) monolith electronic conductivity of 11–14 Scm and micropore size of 0.6–0.8 nm for HO, K and HSO , and of 0.85–0.95 nm for OH; (ii) electrolyte ionic conductivity above 600 mScm and 6M KOH electrolyte, since this electrolyte performs better than 2M HSO and 1M KOH. Authors thank Prof. A. Linares-Solano, now retired, for providing the pristine carbon monoliths and for helpful discussions about carbon materials. Authors also thank Prof. G.Z. Chen from Univ. Nottingham (UK) for helpful discussions about OCP and PZC. Javier Toro and Edurne Laurín are acknowledged for technical assistance of electrochemical and SEM measurements, respectively. Funding through the PID2019-104717RB-I00 project is acknowledged to Spanish MICINN. |
| Databáze: | OpenAIRE |
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