Thermally reduced graphite oxide as positive electrode in Vanadium Redox Flow Batteries

[EN] Two graphene-like materials, obtained by thermal exfoliation and reduction of a graphite oxide at 700 and 1000 °C, were studied as active electrodes in the positive half-cell of a Vanadium Redox Flow Battery (VRFB). In particular, that obtained at 1000 °C exhibited an outstanding electrochemical performance in terms of peak current densities (30.54 and 30.05 mA cm−2 for the anodic and cathodic peaks at 1 mV s−1, respectively) and reversibility (ΔEp = 0.07 V). This excellent behavior is attributed to the restoration of sp2 domains after thermal treatment, which implies the production of a graphene-like material with a high electrical conductivity and accessible surface area. Moreover, the residual functional groups, –OH, act as active sites towards the vanadium redox reactions. This represents a significant step forward in the development of highly effective VRFB electrode materials.

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Bibliographic Details
Main Authors: González Arias, Zoraida, Botas Velasco, Cristina, Álvarez Rodríguez, Patricia, Roldán Luna, Silvia, Blanco Rodríguez, Clara, Santamaría Ramírez, Ricardo, Granda Ferreira, Marcos, Menéndez López, Rosa María
Format: artículo biblioteca
Language:English
Published: Elsevier 2012-03
Subjects:Graphite oxide, VRFB,
Online Access:http://hdl.handle.net/10261/88991
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Summary:[EN] Two graphene-like materials, obtained by thermal exfoliation and reduction of a graphite oxide at 700 and 1000 °C, were studied as active electrodes in the positive half-cell of a Vanadium Redox Flow Battery (VRFB). In particular, that obtained at 1000 °C exhibited an outstanding electrochemical performance in terms of peak current densities (30.54 and 30.05 mA cm−2 for the anodic and cathodic peaks at 1 mV s−1, respectively) and reversibility (ΔEp = 0.07 V). This excellent behavior is attributed to the restoration of sp2 domains after thermal treatment, which implies the production of a graphene-like material with a high electrical conductivity and accessible surface area. Moreover, the residual functional groups, –OH, act as active sites towards the vanadium redox reactions. This represents a significant step forward in the development of highly effective VRFB electrode materials.