Research Articles (SAIAMC)

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Browsing by Author "Bladergroen, Bernard Jan"

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    Development of FeCux/FeS/Graphite composite electrode materials for iron-based Alkaline batteries
    (Electrochemical Science Group, University of Belgrade, 2020) Tawonezvi, Tendai; Bladergroen, Bernard Jan; John, Joe
    In an attempt to enhance the electrochemical performance of the iron-based electrode, an iron-core copper-shell nano-structured material was synthesized and incorporated with ferrous sulphide, and graphite additives. An electrically conductive nickel mesh as a current collector, coupled with a low-cost hot-pressing technique, was employed to formulate the electrodes. The ferrous and graphite integrated iron-core copper-shell nano-structured negative electrode was investigated for applications in Fe-based alkaline batteries energy storage. FeCu0.25/15%FeS/5%C composite electrode delivered a specific discharge capacity of 385 mAh g-1 an approximately 71% coulombic efficiency. The nominal specific capacity of the electrode exhibited negligible capacity degradation after 40 cycles. Ex-situ X-ray Diffraction characterisations and scanning electrode microscopy images of both the fresh and the discharged electrode surfaces show that particle arrangement was still intact after 40 cycles, with negligible particle agglomeration compared to the pure iron electrode surface which was marked with massive agglomeration.
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    Enhanced performance of polybenzimidazole-based high temperature proton exchange membrane fuel cell with gas diffusion electrodes prepared by automatic catalyst spraying under irradiation technique
    (Elsevier, 2013) Su, Huaneng; Pasupathi, Sivakumar; Bladergroen, Bernard Jan; Linkov, Vladimir; Pollet, Bruno G.
    Gas diffusion electrodes (GDEs) prepared by a novel automatic catalyst spraying under irradiation (ACSUI) technique are investigated for improving the performance of phosphoric acid (PA)-doped polybenzimidazole (PBI) high temperature proton exchange membrane fuel cell (PEMFC). The physical properties of the GDEs are characterized by pore size distribution and scanning electron microscopy (SEM). The electrochemical properties of the membrane electrode assembly (MEA) with the GDEs are evaluated and analyzed by polarization curve, cyclic voltammetry (CV) and electrochemistry impedance spectroscopy (EIS). Effects of PTFE binder content, PA impregnation and heat treatment on the GDEs are investigated to determine the optimum performance of the single cell. At ambient pressure and 160 o C, the maximum power density can reach 0.61 W cm-2, and the current density at 0.6 V is up to 0.38 A cm-2, with H /air and a platinum loading of 0.5 mg cm-2 on both electrodes. The MEA with the GDEs shows good stability for fuel cell operating in a short term durability test.
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    Membrane electrode assemblies with low noble metal loadings for hydrogen production from solid polymer electrolyte water electrolysis
    (Elsevier, 2013) Su, Huaneng; Linkov, Vladimir; Bladergroen, Bernard Jan
    High performance membrane electrode assemblies (MEAs) with low noble metal loadings (NMLs) were developed for solid polymer electrolyte (SPE) water electrolysis. The electro- chemical and physical characterization of the MEAs was performed by IeV curves, elec- trochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Even though the total NML was lowered to 0.38 mg cm-2, it still reached a high performance of 1.633 V at 2 A cm-2 and 80 o C, with IrO2 as anode catalyst. The influences of the ionomer content in the anode catalyst layer (CL) and the cell temperature were investigated with the purpose of optimizing the performance. SEM and EIS measurements revealed that the MEA with low NML has very thin porous cathode and anode CLs that get intimate contact with the electrolyte membrane, which makes a reduced mass transport limitation and lower ohmic resistance of the MEA. A short-term water electrolysis operation at 1 A cm-2 showed that the MEA has good stability: the cell voltage maintained at ~1.60 V without distinct degradation after 122 h operation at 80 o C and atmospheric pressure.
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    Optimization of gas diffusion electrode for polybenzimidazole-based high temperature proton exchange membrane fuel cell: Evaluation of polymer binders in catalyst layer
    (Elsevier, 2013) Su, Huaneng; Pasupathi, Sivakumar; Bladergroen, Bernard Jan; Linkov, Vladimir; Pollet, Bruno G.
    Gas diffusion electrodes (GDEs) prepared with various polymer binders in their catalyst layers (CLs) were investigated to optimize the performance of phosphoric acid doped polybenzimidazole (PBI)-based high temperature proton exchange membrane fuel cells (HT-PEMFCs). The properties of these binders in the CLs were evaluated by structure characterization, electrochemical analysis, single cell polarization and durability test. The results showed that polytetrafluoroethylene (PTFE) and polyvinylidene difluoride (PVDF) are more attractive as CL binders than conventional PBI or Nafion binder. At ambient pressure and 160 o C, the maximum power density can reach w 0.61 W cm-2 (PTFE GDE), and the current density at 0.6 V is up to ca. 0.52 A cm-2 (PVDF GDE), with H2/air and a platinum loading of 0.5 mg cm-2 on these electrodes. Also, both GDEs showed good stability for fuel cell operation in a short term durability test.
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    Synthesis, characterisation and evaluation of IrO2 based binary metal oxide electrocatalysts for oxygen evolution reaction
    (Electochemical Society Inc., 2012) Felix, Cecil; Maiyalagan, Thandavarayan; Pasupathi, Sivakumar; Bladergroen, Bernard Jan; Linkov, Vladimir
    IrO2, IrxRu1-xO2, IrxSnx-1O2 and IrxTax-1O2 (1 ≥ x ≥ 0.7) were synthesized, characterised and evaluated as electrocatalysts for the oxygen evolution reaction in solid polymer electrolyte electrolysers. The electrocatalysts were synthesised by adapting the Adams fusion method. The physical properties of the electrocatalysts were characterised by scanning electron microscopy, transmission electron microscopy and x-ray diffraction. Electrochemical activity of the electrocatalysts toward the oxygen evolution reaction was evaluated by cyclic voltammetry and chronoamperometry. X-ray diffraction revealed no phase separation when RuO2 or SnO2 was introduced into the IrO2 lattice suggesting that solid solutions were formed. Transmission electron microscope analysis revealed nanosize particles for all synthesised metal oxides. Crystallinity increased with the addition of RuO2 and SnO2 while a suppression of crystal growth was observed with the addition of Ta2O5 to IrO2. Chronoamperometry revealed that the addition of all the secondary metal oxides to IrO2 resulted in improved catalytic performance. Ir0.7Ru0.3O2 was identified as the most promising electrocatalyst for the oxygen evolution reaction. Keywords: