Equilibrium concentrations of dissolved platinum species from a electrocatalyst sample in 0.5 M at 80°C were found to increase with applied potential 0.9 1.1 V vs reversible hydrogen electrode. In addition, surface area loss for short-stack proton exchange membrane fuel cells (PEMFCs) operated open-circuit voltage was shown be higher than another under load . Both findings suggest that the formation soluble (such as ) plays an important role PEMFC electrodes. As accelerated cathode (from 63...

Heterostructured interfaces of oxides, which can exhibit transport and reactivity characteristics remarkably different from those bulk are interesting systems to explore in search highly active cathodes for the oxygen reduction reaction (ORR). Here, we show that ORR ∼85 nm thick La0.8Sr0.2CoO3−δ (LSC113) films prepared by pulsed laser deposition on (001)-oriented yttria-stabilized zirconia (YSZ) substrates is dramatically enhanced (∼3−4 orders magnitude above LSC113) surface decorations...

The active ingredient: La0.8Sr0.2CoO3−δ (LSC) epitaxial thin films are prepared on (001)-oriented yttria-stabilized zirconia (YSZ) single crystals with a gadolinium-doped ceria (GDC) buffer layer (see picture). LSC exhibit better oxygen reduction kinetics than bulk LSC. enhanced activity is attributed in part to higher nonstoichiometry. Detailed facts of importance specialist readers published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They...

The application of silicon microfabrication technologies to electrochemical devices allows reduction overall device package potentially increase volumetric power densities. This review first focuses on some exciting developments in microfuel cells, particular, solid oxide fuel cells (SOFCs) and proton exchange membrane (PEMFCs). emphasis is given innovative 2D processing methods, novel architectures demonstrated performance terms area Emerging 3D fabrication techniques that are promising...

cathodes used in solid oxide fuel cells have exhibited enhanced catalytic activity after polarization; however, the origin of this enhancement is not understood. In study, dense thin-film microelectrodes fabricated by sputtering were cathodically or anodically polarized, and electrochemical impedance spectroscopy was to examine changes for oxygen reduction reaction (ORR) before polarization. Scanning electron atomic force microscopy revealed surface microstructural Surface compositions thin...

Abstract Widespread adoption of redox flow batteries (RFBs) for renewable energy storage is inhibited by a relatively high cost storage. This due largely to typical RFBs requiring two flows, external tanks, and expensive ion‐exchange membranes. Here, we propose potentially inexpensive Zn‐Br 2 RFB which membraneless requires only single flow. The an emulsion consisting continuous, Br ‐poor aqueous phase dispersed, ‐rich polybromide phase, pumped through the channel separating anode cathode....

Dense microelectrodes fabricated with well-defined microstructures and geometries using microelectronic fabrication techniques were studied electrochemical impedance spectroscopy (EIS) to investigate the rate-limiting reaction step(s) for oxygen reduction (ORR) on (LSM)/ -stabilized (8YSZ) system. At least four distinct processes observed ORR LSM/8YSZ under ambient at intermediate temperatures, which have been assigned tentatively to: (i) ion transport in 8YSZ an average activation energy of...

The surface oxygen exchange kinetics occurring on dense ( thick) and thin films were investigated by electrochemical impedance spectroscopy (EIS). Rutherford backscattering revealed that the bulk film compositions consistent with nominal stoichiometry, having a slight Fe deficiency. Surface of enriched in La using X-ray photoelectron Auger electron spectroscopy. EIS data utilized to determine coefficients, , range temperatures from partial pressures . magnitudes found comparable for both...

Films of La0.8Sr0.2CoO3-δ (LSC-82) with 45 and 90 nm thickness were grown epitaxially on (001) oriented single crystal yttria-stabilized zirconia a thin gadolinium-doped ceria interlayer using pulsed laser deposition, characterized X-ray diffraction (XRD), depth-profile secondary mass spectrometry (DP-SIMS), linear nonlinear electrochemical impedance spectroscopy (EIS NLEIS). The films found to exhibit in-plane tensile strain normal compressive (with overall increased lattice volume)...

Oxygen reduction reaction (ORR) kinetics was investigated on dense microelectrodes as a function of temperature and microelectrode thickness using electrochemical impedance spectroscopy. The surface oxygen exchange mixed bulk/three-phase-boundary (TPB) charge transfer process were found to control ORR at high low temperatures, respectively. transition from the bulk/TPB be highly dependent ( for vs ). These findings can used guide design electrodes that operate intermediate temperatures.

Platinum is considered a promising electrocatalyst in solid oxide fuel cells (SOFCs) for micro and portable applications. Although the platinum/YSZ system has been studied extensively, numerous open questions remain with regard to oxygen reduction reaction (ORR) mechanism at molecular level. It proposed that limiting steps may include dissociative adsorption of oxygen, surface diffusion species migration electrolyte (charge transfer) through three-phase boundaries. In this study, dense...

Sr-doped LaMnO3 (LSM)/Yttria-stabilized Zirconia (YSZ) are the conventional cathode/electrolyte materials for SOFCs. However, mechanisms that occur during oxygen reduction reaction (ORR) at interface still unclear and have been a roadblock further enhancement of SOFC performance, especially low-temperatures. For this study, LSM is fabricated on sputtered single crystal YSZ by thin-film techniques patterned via photolithography to obtain precise microelectrodes. EIS results microeletrodes...

In this study, we describe multi-cell SC-SOFC architectures with multiple different electrode/electrolyte systems. These SC-SOFCs are fabricated using thin-film techniques and patterned via photolithography. Micro feature dimensions ranging from 5μm to 200μm successfully constructed repeatable. An OCV of approximately 380mV at 400{degree sign}C was found when methane air gases. values were decrease increasing temperature a sign change in voltage observed around 575{degree sign}C. Future...

Oxygen reduction reactions (ORR) on La1−xSrxMnO3−d are currently not well understood and no final agreement the precise oxygen rate-determining step(s) has been made. To investigate ORR, we fabricated thin-film microelectrodes of platinum (Pt) by RF-sputtering patterning via photolithography to obtain precisely defined electrode geometries features. These were then tested using impedance spectroscopy under varying conditions such as DC bias, partial pressure, current treatment. For Pt...

The Cover Feature shows the potential societal impact of a single-flow battery leveraging multiphase flow. By promising inexpensive energy storage, such can be used to store solar during day for powering cities at night. More information found in Full Paper by L. Amit et al.