bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on Protocols for Evaluating Durability of PEFC Electrolyte Membranes
Authors: Oono Yuka , Kobayashi Kenji , Hori Michio 
Published: February 2020

Introduction

Under the NEDO Project called Cell Evaluation Project, Daido University(DU) decided the evaluation protocol of membrane chemical and mechanical durability based on the protocol recommended by FCCJ and DOE. Table1 and Table 2 shows the OCV and Dry-wet cycle test protocols were decided by DU. Using these protocols, chemical durability and mechanical durability of fluorine based and hydrocarbon membranes from all over the world have been evaluated with single cells.
Regarding to OCV test protocol, the criterion of this test is set which quantity of cross leak current reached at 10 times of the initial current. As the OCV test is going, chemical degradation of membranes are caused by hydrogen peroxide is produced, and then membranes are gradually broken and finally hydrogen leak current larger increase.
Recently, the protocol that combined a OCV test and a Dry-wet cycle test has been suggested by ENE-FORM companies to evaluate and accelerate membranes chemical and mechanical durability of membranes.
In this study, to clarify the degree of the chemical degradation of hydrocarbon-based membranes in the OCV test, DU examine a newly protocol of evaluating for membrane’s chemical durability by OCV test with the new diagnosis method to use dry-wet cycle test.

Experimental

Table3 shows DU newly protocol for membrane chemical durability based on the protocol recommended by ENE-FORM companies. As seen this table, OCV tests with diagnosis method of membrane’s chemical durability were conducted on single cells with Nafion HP membrane and hydrocarbon-based membranes. Dry-wet cycle test was conducted for diagnosis method to evaluate degree of membrane chemical durability.

Acknowledgement

This research was performed under a grant from the Cell Evaluation Project from the New Energy and Industrial Technology Development Organization (NEDO) .
Invited: Confinement Effects on the Structure and Transport of Nafion Ultrathin Films
Authors: Stafford Christopher M. , Page Kirt , Davis Eric M. , Kim Sangcheol , Dura Joseph , Yager Kevin , Kusoglu Ahmet , Soles Christopher L. 
Published: February 2020

Polymer electrolyte membrane (PEM)-based fuel cells are being aggressively targeted as an alternative energy source for transportation and stationary power due to their high charge density and low operating temperatures. While the structure, transport and mechanical properties of bulk PEMs have been extensively studied, there is increasing interest on the behavior of these materials at interfaces and under confinement, since there exist many heterogeneous interfaces within an actual fuel cell assembly. One could argue that the performance and ultimate failure of the membrane electrode assembly is greatly impacted by the structure and transport of ionomers confined to extremely small length-scales.
Using a combination of neutron and x-ray reflectivity, grazing-incidence small-angle x-ray scattering (GISAXS), quartz crystal microbalance (QCM), polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS), as well as measurements capable of measuring thin-film mechanics we have studied the water transport and mechanical behavior as a function of humidity and initial film thickness (< 220 nm). Our previous work has shown that when the polyelectrolyte is confined to thin films there is suppression in both swelling and water diffusivity in addition to considerable changes in the nano-scale structure.
More recently, we have developed methods to measure the mechanical properties of these systems, as well as extended our PM-IRRAS method to attempt to answer questions about the roles interfacial mass transport and polymer chain relaxations. The mechanical methods reveal an effect of confinement on the measured stiffness of the material. Specifically, we observe an increase in the modulus with decreasing film thickness and, in the beginning of the hydration process, a visco-plastic response due to swelling. These results lend some explanation to the observed decrease in water uptake with decreasing film thickness.
Moreover, we have extended our use of PM-IRRAS to include in-situ vapor switching between H2O and D2O. In this approach, we measure the time-resolved diffusion of H2O into the film (swelling), followed by the diffusive exchange of D2O for H2O (switch), and then then loss of H2O upon drying (deswelling). The experiments enable us to (1) eliminate contributions of swelling and relaxation to the measured transport of water and (2) measure the transport in a pseudo-steady state manner. This method shows promise in answering questions about the dominant mechanism for transport in confined thin films.
Collectively, our program aims to provide a comprehensive understanding of the effect of confinement on the structure and transport of ionomer-based materials, and how these effects manifest themselves in the performance and mechanical response of such membranes.
Validation of the Influence of Test Parameters in Performance Measurements of a PEMFC Stack
Authors: Harms Corinna , Köhrmann Frank , Dyck Alexander 
Published: February 2020

Uniform testing procedures for the characterisation of PEMFC stacks are important due to the necessity to achieve comparable and reliable results. The comparability of different stacks is relevant for stack manufacturers as well as for system integrators and for academic research. Results generated in different laboratories can be influenced by different test stands, test procedures and diverse environmental conditions.
Harmonized testing procedures for PEMFC stacks were developed within the EU project “Development of PEM Fuel Cell Stack Reference Test Procedures for Industry” (Stack-Test) regarding performance, durability and safety aspects for automotive, portable and stationary applications. The testing procedures for performance measurements were developed in order to investigate the sensitivity of stacks to the operating parameters.
The testing procedures for performance measurements developed by the project partners were validated using a set of PEMFC stacks. For the measurements the input parameters have to be defined and controlled in a precise way. By varying the input parameters like temperature, relative humidity and stoichiometry the effect on the main output parameters like the single cell voltages and the overall stack voltage is monitored. The effect on the voltage was evaluated by the variation of the electrical load. Additionally, current voltage curves at different parameters e. g. with a set of temperatures were generated.
An overview on the achieved results will be given, to describe the optimization pathway for stack characterization under manufacture defined conditions. With these procedures it is possible to achieve reproducible and stable results to be applied by stack manufactures and system integrators for reliable fuel cell stacks.
The research leading to these results is part of the EU project Stack-Test which has received funding from the European Union´s Seventh Framework Programme (FP/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement n° [3034445]. We acknowledge the preparation of the test modules used for this validation by the project partners within the Stack-Test project. The test modules are available for further revision on the project website: stacktest.zsw-bw.de
Fabrication and Cell Analysis of a Pt/SiO2 Platinum Thin Film Electrode
Authors: Inaba Masanori , Suzuki Takahisa , Hatanaka Tatsuya , Morimoto Yu 
Published: February 2020

Platinum thin film electrodes, such as nanostructured thin film (NSTF) by 3M [1], have attracted much attention as alternative catalysts for polymer electrolyte fuel cells (PEFCs). Although NSTF electrodes showed higher efficiency and power density than conventional Pt/C electrodes under suitable operating conditions, it has been reported that they tend to show larger performance decline under dry or wet conditions [2]. To examine all those properties of NSTF on other thin film electrodes and reveal their general features, in this research we fabricated a platinum thin film electrode on the surface of SiO2 nanofibers. Performances of the cell with the electrode were studied and its various properties were analyzed.
Platinum was deposited on a SiO2 nanofiber web (Japan Vilene Company, Ltd., 200 nm in fiber diameter and 6 mm in web thickness) by atomic layer deposition. An SEM image of the cross section of the Pt/ SiO2 nanofiber electrode is shown in Fig. 1. The SiO2 nanofibers are covered with a platinum thin film of 3 nm in thickness. Nafion membrane was sandwiched between the Pt/SiO2 nanofiber electrode as a cathode and a conventional Pt/C electrode as an anode to form an MEA. Note that no ionomer was impregnated on the Pt/SiO2 nanofiber electrode. Fuel cell polarization curves were obtained using 1 cm2 single-cell hardware with cross-flow flowfields under various conditions. The electrochemical surface area (ECSA), proton conductivity and oxygen transport resistance were analyzed by cyclic voltammetry, electrochemical impedance measurement, and diffusion-limited current measurement using diluted oxygen, respectively.
Polarization curves and analyzed results were shown in Fig. 2 and Table 1, respectively, in comparison with those of conventional Pt/C electrode. The Pt/SiO2 cell showed comparable performance to the Pt/C cell at 100% RH in spite of the much smaller ECSA. At 40% RH, however, the Pt/SiO2 cell showed lower performance than the Pt/C cell.
A transmission line model of the electrode was applied to the Pt/SiO2 nanofiber electrode to analyze the performance loss. By following the model, the reaction resistance was calculated using values of the cathode resistance and the ohmic resistance, which were obtained from slopes of the polarization curves and the proton conductivity, respectively. The analyzed results under various RH conditions are shown in Fig. 3. The reaction resistance significantly increases with decreasing RH, while the ohmic resistance increase is limited. This indicates that the performance loss of the Pt/SiO2 nanofiber electrode under dry condition is mainly due to the increase in the reaction resistance.
Oxygen transport resistance, performances in wet conditions, and the effects of ionomer impregnation on the Pt/SiO2 electrode will also be discussed.
[1] M. K. Debe, J. Electrochem. Soc., 2013, 160, F552
[2] A. Kongkanand, et al., J. Electrochem. Soc., 2012, 159, F405
Water/Methanol Transport in Polyethylene Based Block Copolymers as Anion Conductors for Applications in Fuel Cells
Authors: Sarode Himanshu N , Yang Yuan , Herring Andrew M 
Published: February 2020

Anion exchange membranes have been a central point of focus for the low temperature fuel cell application. The primary goal of AEMs in fuel cells is to transport hydroxide (OH-) ions from cathode to anode and to act as a separator between the electrodes.
In this work we have studied a block copolymer of polyethylene and polyvinyl benzyl trimethyl ammonium bromide (PE-b-PVBTMA[Br], Fig. 1) for various transport properties. By using the dynamic vapor sorption apparatus we were able to study water and methanol uptake dynamics for this AEM. Fickian diffusion coefficients for both water and methanol were calculated during this study giving idea about the solvent uptake kinetics.
We also measured the conductivity of the AEM under 95% relative humidity (Figure 2). It was found that the AEM followed VFT theory behavior for transporting ions through it as opposed to the classical Arrhenius behavior. VFT behavior suggests that ion transport in the membrane is facilitated by the polymer chain motion as opposed to ion transport in water which is governed mainly by the Arrhenius type of behavior.
We also report methanol/water ion transport using the pulse gradient stimulated spin echo (PGSTE) NMR technique to determine the tortuosity of the membrane along with self diffusion of each species.

Acknowledgements:

We would like to thank the Army Research Office for funding this Multidisciplinary University Research Initiative under contract #W911NF-10-1-0520 and the Colorado School of Mines NMR facility, funded by National Science Foundation under the grant CHE-0923537. We would like to thank Yifan Li, D M Knauss for providing with the polymer for this study.
Photoelectrochemical Characterization of Photosystem I Encapsulated in Nafion
Authors: Baker David R. , Simmerman Richard , Sumner James J , Bruce Barry D , Lundgren Cynthia A. 
Published: February 2020

As battlefield technologies continue to become more advanced and energy intensive, there is an increased cost and a higher exposure to hazards when supplying fuels to meet the power demand of these applications. This has created a great need to reduce the amount of energy delivered in the field, and has introduced a need for on-site fuel generation to reduce the logistical burden.
Solar derived fuels are a leading area of research for on-site fuel generation because of the ubiquity of solar energy. The biomimetic approach of converting solar to useful energy, simulating photosynthesis, employs the highly efficient photosynthetic protein Photosystem I (PSI) to reduce water to H2 which would in turn be used to fuel combustion engines or fuel cells. Any device deployed in the field would need to be designed for portable applications. Therefore, a robust and electrochemically active electrode must be developed which allows PSI to access both light and aqueous electrolyte solutions.
This presentation relates recent work with encapsulating PSI and the redox mediator Os(bpy)2Cl2 in a Nafion polymeric film. Because of surface charges in Nafion’s water-filled pores both PSI and Os(bpy)2Cl2 are trapped in the polymer matrix whereas the positively charged methyl viologen (MV) redox mediator is able to diffuse through the film. The films are characterized for their stability and photoelectrochemical performance resulting in their capability to load PSI in the films at very high surface densities. The use of Nafion makes the film more stable than other redox polymers tested, and the high surface densities of PSI opens the door to higher photocurrents.
Analytical Application of Intercalation Processes
Authors: Lipkin Semen M. , Lipkin Mikhail Semenovich , Sedov Andrey Vladimirovich , Onyshko Dmitry Anatolievich 
Published: February 2020

An analisys of alloy directly on surface example is interesting for many applications. Electrochemical methods, used in solving this problem, provide variability, low cost, minimal example treatment and informational content of analytic signal.
All the advantages of electrochemical nondestructive alloy analisys can be realized by using appropriate electrode processes. We assume that intercalation is one these processes due to its high sensitivity to host structure composition. It was shown, that pulse chronopotentiometry is the most appropriate method for different intercalation processes.
Use of intercalation process type is determined mainly by nature of analyzed component. So, for metals with high overpotential it is convenient to use anodic intercalation in alkaline electrolytes or reduction of anodic oxide.
For metals with low overpotential (Au, Cu, Ag, Pt) intercalation of water and anions in anodic part of polarization give easy reductive adsorbed complex ions and their inverse reduction is displayed as a horizontal part on chronopotentiometry curve (Fig. 1). A length of such part is proportional to alloy component content, which provides analysis possibility.
Cathodic intercalation of lithium ions from acetonitrile electrolyte makes a basis of carbon determination in steels. Pulse chronopotentiograms of this process (fig. 2) have plato, which length change is proportional to carbon content.
Thus, electrochemical nondestructive alloy analisys on the base of intercalation processes is perspective adaptive method with a much of various tunning-up parameters.
Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) for In-Situ Analysis of Solid Oxide Electrolysis Cells
Authors: Elder Rachael H , Cumming Denis J , Taylor Rebecca , Hardacre Chris 
Published: February 2020

High temperature co-electrolysis of steam and carbon dioxide using a solid oxide cell (SOC) has been shown to be an efficient route to produce syngas (CO + H2), which can then be converted to synthetic fuel. Optimization of co-electrolysis requires detailed understanding of the complex reactions, transport processes and degradation mechanisms occurring in the SOC during operation. Currently, electrochemical measurements are conducted in-situ during electrolysis operation, however many analytical techniques are only used ex-situ, before and/or after electrolysis operation. In some cases the analytical techniques used are destructive (e.g. SEM imaging of the cell microstructure). In order to fully understand and characterize co-electrolysis in SOCs, in-situ monitoring of the reactants, products, and the cell itself are necessary.
As part of the UK-wide £5.7m 4CU project (A Comprehensive, Coordinated Programme for Carbon Capture and Utilisation Research) we are developing a suite of in-situ characterization techniques for high temperature SOC operation. In this paper we report the use of DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) to probe the reactions occurring during dry CO2 electrolysis and co-electrolysis.
The design and commissioning of the rig for in-situ characterization will be presented, along with a discussion on the challenges of spectroscopic access to the areas of interest of an SOC operating at high temperature. Infrared spectra showing CO adsorption on Ni-YSZ powdered catalyst and electrode surfaces will be presented.
Electrochemical Investigation of Nitinol/Tantalum Hybrid Surfaces Modiﬁed with Phosphonic Acid Derivatives
Authors: Mekhalif Zineb , Maho Anthony , Devillers Sébastien , Vanhooland Annelies , Delhalle Joseph 
Published: February 2020

Nitinol, a nickel and titanium alloy in quasi-equiatomic proportions, is used in numerous biomedical applications due to its remarkable mechanical characteristics, its resistance towards corrosion and good biocompatibility. Further research to reinforce osseointegrative abilities and barrier properties towards external aggressive agents are still needed.
In this context, electrochemical methods can be used to generate protective and functional surface coatings on Nitinol substrates with a good level of control and versatility. Specifically here are considered the elaboration of a structured thin layer on Nitinol plates by electrodeposition of tantalum and its subsequent modification by the self-assembly of phosphonic acid derivatives to consolidate corrosion protection and bioactivity features.
Electrochemical techniques are also used to assess and study the different deposited layers. Cyclic voltammetry, polarization curves, free potential measurements, and scanning electrochemical microscopy experiments are performed to qualitatively and quantitatively evaluate electron and mass transfers at the interface, as well as corrosion resistance properties. Spectroscopic (XPS) and microscopic (SEM) analyses complete the characterization process regarding chemical nature and morphology aspects.
Surface Modification of Mg Alloys for Controlled Biodegradation Behavior
Authors: Virtanen Sannakaisa 
Published: February 2020

Mg based materials are in the focus of interest to be used as biodegradable metals, for biomedical applications where the device is only required for a certain time of healing. However, the corrosion behavior of today’s alloys is for many targeted applications too fast. Therefore, in addition to design of novel alloys, research is searching for biocompatible coatings and surface modifications of Mg alloys. The surface modification should at the same time optimize the corrosion behavior and the biological performance.
The presentation will present recents efforts in Mg alloy surface modification. One of the simplest approaches is biomimetic formation of conversion coatings in simulated body fluids. Such layers can significantly slow down dissolution, and can be beneficial for cell adhesion on Mg surfaces. Other approaches currently under investigation are surface functionalization by protein coatings and control of surface wettability by organic monolayers on morphologically-modified Mg surfaces. In addition, we will discuss the preparation and performance of biodegradable polymer coatings on Mg surfaces. Critical issues such as long-term corrosion protection or coating adhesion will be addressed.
Selective Detection by Dpv of Benserazide and Levodopa in Pharmaceutical Preparates
Authors: Dávila Martín Marino , Ruíz Patricia , Elizalde Maria De la Paz 
Published: February 2020

For the detection of some important biological substances by electrochemical methods the carbon modified electrodes have been widely used [1-3]. The aim of this work was to study the simultaneous detection of benserazide and levodopa in pharmaceutical tablets of MADOPAR® by the voltammetric method using a modified C-PVC electrode. The preparation and modification of the C-PVC electrode was performed according to the previously reported method [4]. The tablet extract in presence of excipients of MADOPAR® in phosphates buffer pH 7.4 was used for the measurements without pretreatment. The electrochemical experiment by VDP of the MADOPAR®extract using the C-PVC modified electrode showed good defined oxidation peaks for benserazide at 24 mV and levodopa at 141 mV. The oxidation current was proportional to the volume of the extract in the buffer solution (Fig.1). The presence of an excess of ascorbic acid (140 µM) did not affect the detection of benserazide and levodopa. The modified C-PVC electrode can be used for the simultaneous determination of benserazide and levodopa in some real samples at different pH values of buffer solutions.
References
[1] J.B. Raoof, R. Ojani, M. Amiri-Aref, M. Baghayeri; Sens. Actuators, B. 166–167 (2012) 508–518.
[2] EB Sakineh, B Hadi, KM Hassan, SN Somayeh, SN Vahhab, R Sara; J Anal Meth Chem 2012 (2012) 1-8.
[3] Mu Naushad, VK Gupta, SM Wabaidur, ZA Alothman; Int J Electrochem Sci. 8 (2013) 297-311.
[4] P.Ruiz-G, M.P. Elizalde-G, M.M Davila, Esp. Pat., Appl. P201430231 (2014).
Acknowledgments
We acknowledge the financial support of CUVyTT-BUAP under project No.014.