Philippe Knauth; Maria Luisa Di Vona
Abstract
Electrochemical synthesis is a powerful tool for the preparation of conformal, thin solid electrolytes directly on the electrodes, particularly with complex shapes, such as nanostructured electrodes. Such separators should present the highest possible single ion conductivity, negligible electronic conductivity ...
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Electrochemical synthesis is a powerful tool for the preparation of conformal, thin solid electrolytes directly on the electrodes, particularly with complex shapes, such as nanostructured electrodes. Such separators should present the highest possible single ion conductivity, negligible electronic conductivity combined with high chemical and mechanical stability. These requirements drive our development work: we synthesize polymers with excellent mechanical properties, which are decisive for a high durability of the separators. The single-ion conductivity is assured by anchoring the counter-ions on the polymer backbone. The solid polymer electrolytes contain no flammable solvent guaranteeing high safety. For cation-conducting membranes, we synthesized polymers with sulfonate groups grafted on the macromolecular chain. These ionomers, including poly(styrene sulfonate) (PSS) can be used for proton exchange membrane fuel cells and Li batteries. Anion-conducting membranes contain quaternary ammonium as fixed cationic groups; they can be applied for example in hydroxide exchange membrane fuel cells. The paper presents the electrochemical synthesis procedures and the relevant structural, microstructural and electrical properties of cation- and anion-conducting polymers, including relevant data of applications, such as Li microbattery cycling.
Giordano T. Paganoto; Josimar Ribeiro
Abstract
Ni and Ga elements are inexpensive compared to the Pt. Ni and NiOx have been recognized to have potential applications in ethanol electrooxidation. For these reasons and based on previous results obtained with Ga addition on Pt-based electrocatalysts we have investigated the PtSn/C electrocatalysts modified ...
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Ni and Ga elements are inexpensive compared to the Pt. Ni and NiOx have been recognized to have potential applications in ethanol electrooxidation. For these reasons and based on previous results obtained with Ga addition on Pt-based electrocatalysts we have investigated the PtSn/C electrocatalysts modified with Ni and Ga. The PtSnNiGa/C electrocatalysts were characterized in acidic medium by electrochemical techniques and by physicochemical techniques such as: X-ray diffraction; Energy dispersive X-ray spectroscopy; Transmission electron microscopy. Based on the TEM analyses, the PtSnNiGa/C electrocatalysts show average particle sizes range between 3.6 – 5.5 nm, which is consistent with XRD data. The ethanol oxidation on the PtSnNiGa/C electrocatalysts occurs at lower potentials as compared to the Pt/C. The higher current normalized by Pt mass (2.62 Ag-1Pt), lower susceptibility to poisoning anodic and charge transfer resistance (245 Ω) were obtained for the Pt45Sn22Ni21Ga12/C electrocatalyst.The current normalized by Pt mass: Pt50Sn26Ni12Ga12/C (2.8 Ag -1 Pt); Pt45Sn22Ni21Ga12/C (2.62 Ag -1 Pt); Pt52Sn21Ni18Ga9/C (1.63 Ag -1 Pt) and Pt43Sn23Ni11Ga22/C (1.27 Ag -1 Pt) electrocatalysts are higher compared to binary catalysts with high Pt content. The promotion effect of PtSnNiGa/C to ethanol electrooxidation can be explained by the modification structural of Pt by incorporation of Sn, Ni and/or Ga to the face-centered cubic crystalline of Pt.
Antonios Kelarakis
Abstract
In view of the continuous decline in fossil fuel reserves, at a time when energy demands are steadily increasing, a diverse range of emerging nanotechnologies promise to secure modern solutions to the prehistoric energy problem. Each one of those distinct approaches capitalizes on different principles, ...
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In view of the continuous decline in fossil fuel reserves, at a time when energy demands are steadily increasing, a diverse range of emerging nanotechnologies promise to secure modern solutions to the prehistoric energy problem. Each one of those distinct approaches capitalizes on different principles, concepts and methodologies to address different application requirements, but their common objective is to open a window to a sustainable energy future. Consequently, they all deserve substantial (though not necessarily equal) consideration from the scientific and engineering community. In this review we present bottom-up strategies that show great promise for the development of a new generation of advanced materials for energy applications without compromising the public safety or the environment.