Binder-free supercapacitor electrodes: Optimization of monolithic graphitized carbons by reflux acid treatment

The rational design of electrodes mimicking the cellular structure of natural bio-resources has been a matter of increasing interest for applications in energy storage. Due to their anisotropic and hierarchical porosity, monolithic carbon materials from natural wood precursors are appealing as elect...

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Detalles Bibliográficos
Autores: Gómez-Martín, Aurora, Gutiérrez-Pardo, A., Martínez-Fernández, J., Ramírez-Rico, J.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2020
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/217675
Acceso en línea:http://hdl.handle.net/10261/217675
Access Level:acceso abierto
Palabra clave:Monolithic carbon
Wood
Catalyst
Reflux
Supercapacitors
Descripción
Sumario:The rational design of electrodes mimicking the cellular structure of natural bio-resources has been a matter of increasing interest for applications in energy storage. Due to their anisotropic and hierarchical porosity, monolithic carbon materials from natural wood precursors are appealing as electrodes for supercapacitor applications due to their interconnected channels, relatively low cost and environmentally friendly synthesis process. In this work, a liquid-phase oxidative treatment with refluxing nitric acid at 100 °C for 8 h was performed to enhance the surface properties of beech-derived graphitized carbons treated with an iron catalyst. Microstructural, textural and surface investigations revealed that this strategy was successful in removing amorphous carbon and in functionalizing their surfaces. The crystallinity, accessible surface area, micropore volume and surface functionality of beech-derived carbons were increased upon the reflux treatment. The resulting porous carbon materials were evaluated as binderless monolithic electrodes for supercapacitors applications in aqueous KOH electrolyte. A maximum specific capacitance of 179 F·g and a volumetric capacitance of 89 F·cm in galvanostatic charge/discharge experiments were reached. Monolithic electrodes exhibited good cycling stability, with a capacitance retention over 95% after 10,000 cycles.