Staff directory Raul Benages Vilau

Raul Benages Vilau

SO Postdoctoral Researcher
Severo Ochoa
raul.benages(ELIMINAR)@icn2.cat
Novel Energy-Oriented Materials

Publications

2018

  • Battery and supercapacitor materials in flow cells. Electrochemical energy storage in a LiFePO4/reduced graphene oxide aqueous nanofluid

    Rueda-Garcia D., Cabán-Huertas Z., Sánchez-Ribot S., Marchante C., Benages R., Dubal D.P., Ayyad O., Gómez-Romero P. Electrochimica Acta; 281: 594 - 600. 2018. 10.1016/j.electacta.2018.05.151.

    Exploring conceptual frontiers between batteries, supercapacitors, redox flow batteries (RFBs) and fuel cells (FCs), we have used a battery material (i.e. LiFePO4) and a supercapacitor material (i.e. graphene) in the form of nanoparticles dispersed in an aqueous electrolyte to characterize the electrochemical activity of the resulting electroactive nanofluids. X-ray diffraction, TEM, Raman, XPS and AFM analyses were carried out to characterize the solid LiFePO4 and RGO components. The corresponding electroactive nanofluids were prepared by dispersion in an aqueous Li2SO4 electrolyte and stabilized with Diaminobenzoic Acid (DABA). Cyclic voltammetry measurements were used to analyze their electrochemical behavior in three-electrode cells. Charge-discharge tests of the LiFePO4/RGO (positive) vs. RGO (negative) nanofluids were also performed. Effective utilization of dispersed electroactive particles (ca. 100 mAh/g(LFP) at 1C) was demonstrated, which turned out to be superior to the same LFP material used as solid electrode. A charge-transfer percolation effect provided by the RGO dispersion is proposed as the mechanism for the good performance of LiFePO4 (not coated with carbon!) and RGO Nanofluids. Our results constitute a first step and proof of concept of the possible application of electroactive nanofluid electrodes in alternative flow batteries. © 2018 Elsevier Ltd


  • Hybrid Graphene-Polyoxometalates Nanofluids as Liquid Electrodes for Dual Energy Storage in Novel Flow Cells

    Dubal D.P., Rueda-Garcia D., Marchante C., Benages R., Gomez-Romero P. Chemical Record; 18 (7): 1076 - 1084. 2018. 10.1002/tcr.201700116.

    Solid Hybrid materials abound. But flowing versions of them are new actors in the materials science landscape and in particular for energy applications. This paper presents a new way to deliver nanostructured hybrid materials for energy storage, namely, in the form of nanofluids. We present here the first example of a hybrid electroactive nanofluid (HENFs) combining capacitive and faradaic energy storage mechanisms in a single fluid material. This liquid electrode is composed of reduced graphene oxide and polyoxometalates (rGO-POMs) forming a stable nanocomposite for electrochemical energy storage in novel Nanofluid Flow Cells. Two graphene based hybrid materials (rGO-phosphomolybdate, rGO-PMo12 and rGO-phosphotungstate, rGO-PW12) were synthesized and dispersed with the aid of a surfactant in 1 M H2SO4 aqueous electrolyte to yield highly stable hybrid electroactive nanofluids (HENFs) of low viscosity which were tested in a home-made flow cell under static and continuous flowing conditions. Remarkably, even low concentration rGO-POMs HENFs (0.025 wt%) exhibited high specific capacitances of 273 F/g(rGO-PW12) and 305 F/g(rGO-PMo12) with high specific energy and specific power. Moreover, rGO-POM HENFs show excellent cycling stability (∼95 %) as well as Coulombic efficiency (∼77–79 %) after 2000 cycles. Thus, rGO-POM HENFs effectively behave as real liquid electrodes with excellent properties, demonstrating the possible future application of HENFs for dual energy storage in a new generation of Nanofluid Flow Cells. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim