Effects of Grain Boundaries at the Electrolyte/Cathode Interfaces on Oxygen Reduction Reaction Kinetics of Solid Oxide Fuel Cells

Choi, Mingi; Koo, Ja Yang; Ahn, Minwoo

doi:10.1002/bkcs.11102

Cited by 11 publications

(3 citation statements)

References 35 publications

(102 reference statements)

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“…Because identical platinum electrodes Journal of Nanomaterials were used for all the GO cells, the exchange current density can be regarded as the interfacial reactivity of the GO membrane. For a detailed assessment of the interfacial reaction kinetics, the exchange current densities were calculated using the y-intercept values via the Tafel equation [42][43][44]:…”

Section: Electrochemicalmentioning

confidence: 99%

Designing Carbon/Oxygen Ratios of Graphene Oxide Membranes for Proton Exchange Membrane Fuel Cells

Ahn

Liu

Lee

2019

Journal of Nanomaterials

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Graphene oxide (GO), which is the oxidized form of graphene, has holes and functional groups on the surface and thus has high potential to be used as an electrochemical transport channel material. In this study, differently modified GO membranes are applied as electrolytes of proton exchange membrane fuel cells (PEMFCs) with controlled carbon/oxygen ratios. The critical and desired properties of the electrolyte, such as electron conductivity, proton conductivity, interfacial reactivity, and cell performance are evaluated in identical platinum-sputtered model electrodes. Among them, with the help of an increased concentration of oxygen-containing groups, a GO membrane with a low carbon/oxygen ratio shows a 2.9-fold improved maximum power density and advanced electrochemical properties compared with the pristine GO membrane. The characterization of GO suggests that the redox state of the membrane is an important factor for controlling the proton conductivity, interfacial reactivity, and maximum power density of PEMFCs.

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Section: Electrochemicalmentioning

confidence: 99%

Designing Carbon/Oxygen Ratios of Graphene Oxide Membranes for Proton Exchange Membrane Fuel Cells

Ahn

Liu

Lee

2019

Journal of Nanomaterials

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“…In particular, oxygen-related defect chemistry at the interface between the cathode and electrolyte plays an important role in the overall ORR kinetics (e.g. charge transfer, ion incorporation, ion transport, and gas adsorption) because it affects the reaction barrier significantly [19][20][21]. Moreover, desired oxygen vacancy concentrations could differ for the ORR at the interface and the ion conduction in the bulk electrolyte [22,23].…”

Section: Introductionmentioning

confidence: 99%

Interface engineering of an electrospun nanofiber-based composite cathode for intermediate-temperature solid oxide fuel cells

Kim

Woo

Kim

et al. 2023

Int. J. Extrem. Manuf.

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Sluggish oxygen reduction reaction (ORR) kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells (IT-SOFCs). In particular, engineering the anion defect concentration at a interface between the cathode and electrolyte is important for facilitating ORR kinetics and hence improving the electrochemical performance. We developed the yttria-stabilized zirconia (YSZ) nanofiber-based composite cathode, where the oxygen vacancy concentration is controlled by varying the dopant cation (Y2O3) ratio in the YSZ nanofibers. The composite cathode with the optimized oxygen vacancy concentration exhibits maximum power densities of 2.66 and 1.51 W/cm2 at 700 and 600 °C, respectively, with excellent thermal stability at 700 °C over 500 h under 1.0 A/cm2. Electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) analysis revealed that the high oxygen vacancy concentration in the nanofiber-based scaffold facilitates charge transfer and the incorporation reaction occurred at the interfaces between the cathode and electrolyte. Our results demonstrate the high feasibility and potential of interface engineering for achieving IT-SOFCs with higher performance and stability.

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“…At such interfaces, the ionic conductivities, electronic conductivities, and catalytic activities of the electrode and electrolyte materials directly affect the ORR kinetics because oxygen ions and electrons are required at the TPBs in the ORRs . Thus, tailoring the interfacial properties to facilitate ORR kinetics is crucial to the enhancement of electrode performance and also to the development of SOFCs that operate at reduced temperatures. − Given the importance of the interfacial properties, a number of approaches have been investigated to develop the functional layer at the interfaces between the electrode and the electrolyte to expedite the reaction rates and to extend the reaction sites for ORR. ,− In addition, the use of composite materials that capitalize on the synergetic advantages of the various constituent material properties of the cathode functional layer constitutes the basis of most of these extensively employed methods. ,, …”

Section: Introductionmentioning

confidence: 99%

Rational Design of a Metallic Functional Layer for High-Performance Solid Oxide Fuel Cells

Choi

Hwang

Kim

et al. 2019

ACS Appl. Energy Mater.

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The rational design of the electrode–electrolyte interface plays a crucial role in expediting the oxygen reduction reaction (ORR) kinetics of intermediate-temperature solid oxide fuel cells (IT-SOFCs). We employed metallic functional layers because of their high electrical conductivities and catalytic activities with respect to ORR kinetics. Using electrohydrodynamic (EHD) jet printing, we printed a metallic grid structure at the interface of Sm0.5Sr0.5CoO3−δ (SSC) and Gd0.1Ce0.9O2−δ (GDC) with Al, Ni, and Ag to systematically quantify the effects of the electrical conductivity and catalytic activity on ORR kinetics. Substantial improvements in interfacial properties were achieved with the metallic functional layers, manifested by reducing the polarization resistance to 12.5% of the bare SSC cathode. I–V characterization, electrochemical impedance spectroscopy (EIS) measurements, and distributed relaxation times (DRT) based on impedance fitting enabled the quantitative deconvolution and revealed that the enhanced electrical conductivity of the metallic functional layer was primarily responsible for the increased electrochemical performance compared to the enhanced catalytic activity. The SSC cathode with the Ag functional layer exhibited the highest peak power density of ∼670 mW/cm2 at 650 °C, which was higher than that of the bare SSC cathode by ∼1.8 times.

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Effects of Grain Boundaries at the Electrolyte/Cathode Interfaces on Oxygen Reduction Reaction Kinetics of Solid Oxide Fuel Cells

Cited by 11 publications

References 35 publications

Designing Carbon/Oxygen Ratios of Graphene Oxide Membranes for Proton Exchange Membrane Fuel Cells

Designing Carbon/Oxygen Ratios of Graphene Oxide Membranes for Proton Exchange Membrane Fuel Cells

Interface engineering of an electrospun nanofiber-based composite cathode for intermediate-temperature solid oxide fuel cells

Rational Design of a Metallic Functional Layer for High-Performance Solid Oxide Fuel Cells

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