Enhanced performance of a Bi-modified graphite felt as the positive electrode of a vanadium redox flow battery

[EN] Graphite felt modified with nanodispersed bismuth was studied as electrode in the positive half-cell of a vanadium redox flow battery (VRFB). The felt was easily modified by immersion in a Bi2O3 solution followed by thermal reduction at 450 °C in air. Despite the low metal content (1 at.%) on t...

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Detalles Bibliográficos
Autores: González Arias, Zoraida, Sánchez Sánchez, Ángela, Blanco Rodríguez, Clara, Granda Ferreira, Marcos, Menéndez López, Rosa María, Santamaría Ramírez, Ricardo
Tipo de recurso: artículo
Fecha de publicación:2011
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/88989
Acceso en línea:http://hdl.handle.net/10261/88989
Access Level:acceso abierto
Palabra clave:Vanadium redox flow battery
Graphite felt
Bi-modified electrode
Active surface area
Electrical conductivity
Cyclic voltammetry
Descripción
Sumario:[EN] Graphite felt modified with nanodispersed bismuth was studied as electrode in the positive half-cell of a vanadium redox flow battery (VRFB). The felt was easily modified by immersion in a Bi2O3 solution followed by thermal reduction at 450 °C in air. Despite the low metal content (1 at.%) on the surface of the fibers, the Bi-modified felt showed an excellent electrochemical performance (at 1 mV s− 1) in terms of anodic and cathodic peak current densities (21 and 17 mA cm–2, respectively), reversibility (ΔEp = 0.050 V) and overpotential for the V(IV)/V(V) redox reactions. Furthermore, repetitive cyclic voltammetry measurements, at various scan rates, evidenced the long term stability of this material. These results demonstrate that bismuth nanoparticles on the carbon surface act as stable active sites to promote these reactions, and represent a significant step forward towards the development of outstanding electrode materials for VRFB.