scholarly journals Insight on Single Cell Proton Exchange Membrane Fuel Cell Performance of Pt-Cu/C Cathode

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 544 ◽  
Author(s):  
Marjan Bele ◽  
Matija Gatalo ◽  
Primož Jovanovič ◽  
Francisco Ruiz-Zepeda ◽  
Martin Šala ◽  
...  
Keyword(s):  
Single Cell ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
High Current Density ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Rotating Disc ◽  
Fuel Cell Performance ◽  
Exchange Membrane

The oxygen reduction reaction (ORR) properties of a proprietary PtCu3/C alloy electrocatalyst produced on a multi-gram scale are characterized by the conventional rotating disc electrode (RDE) method and by constructing a membrane electrode assembly (MEA) proton exchange membrane (PEM) single cell. The PtCu3 nanoparticles become porous, enriched in Pt on the surface, and exhibit a high RDE activity. The single cell electrochemical study reveals that, contrary to most advanced catalysts, the high ORR activity can be transferred from the RDE to the MEA. In the latter case, at 0.9VIRfree, a mass activity of 0.53 A/mgPt, at a Pt electrode loading of 0.2 mg/cm2, is achieved. However, at high current density, oxygen transport becomes limited. This is proven by the analysis of polarization curves and electrochemical impedance spectroscopy (EIS) data with a Kulikovsky (physical) model. These indicate that this limitation is caused by the non-optimal microporosity of our catalyst, which hinders the mass transport of oxygen during ORR. Based on our prospective results, one can realistically plan for further efforts to bridge the gap between the RDE and MEA measurements completely and achieve high power densities for Pt-alloy electrocatalysts.

scholarly journals Effect of Stratification of Cathode Catalyst Layers on Durability of Proton Exchange Membrane Fuel Cells

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2975
Author(s):  
Zikhona Nondudule ◽  
Jessica Chamier ◽  
Mahabubur Chowdhury
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
Catalyst Layer ◽  
Cost Effective ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Potential Cycling ◽  
Catalyst Layers ◽  
Exchange Membrane

To decrease the cost of fuel cell manufacturing, the amount of platinum (Pt) in the catalyst layer needs to be reduced. In this study, ionomer gradient membrane electrode assemblies (MEAs) were designed to reduce Pt loading without sacrificing performance and lifetime. A two-layer stratification of the cathode was achieved with varying ratios of 28 wt. % ionomer in the inner layer, on the membrane, and 24 wt. % on the outer layer, coated onto the inner layer. To study the MEA performance, the electrochemical surface area (ECSA), polarization curves, and electrochemical impedance spectroscopy (EIS) responses were evaluated under 20, 60, and 100% relative humidity (RH). The stratified MEA Pt loading was reduced by 12% while maintaining commercial equivalent performance. The optimal two-layer design was achieved when the Pt loading ratio between the layers was 1:6 (inner:outer layer). This MEA showed the highest ECSA and performance at 0.65 V with reduced mass transport losses. The integrity of stratified MEAs with lower Pt loading was evaluated with potential cycling and proved more durable than the monolayer MEA equivalent. The higher ionomer loading adjacent to the membrane and the bi-layer interface of the stratified catalyst layer (CL) increased moisture in the cathode CL, decreasing the degradation rate. Using ionomer stratification to decrease the Pt loading in an MEA yielded a better performance compared to the monolayer MEA design. This study, therefore, contributes to the development of more durable, cost-effective MEAs for low-temperature proton exchange membrane fuel cells.

scholarly journals MOF Derived Catalysts for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cell

2018 ◽  
Vol 778 ◽  
pp. 275-282
Author(s):  
Noaman Khan ◽  
Saim Saher ◽  
Xuan Shi ◽  
Muhammad Noman ◽  
Mujahid Wasim Durani ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Membrane Electrode Assembly ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon ◽  
Exchange Membrane

Highly porous ZIF-67 (Zeolitic imidazole framework) has a conductive crystalline metal organic framework (MOF) structure which was served as a precursor and template for the preparation of nitrogen-doped carbon nanotubes (NCNTs) electrocatalysts. As a first step, the chloroplatinic acid, a platinum (Pt) precursor was infiltrated in ZIF-67 with a precise amount to obtain 0.12 mg.cm-2 Pt loading. Later, the infiltrated structure was calcined at 700°C in Ar:H2 (90:10 vol%) gas mixture. Multi-walled nitrogen-doped carbon nanotubes were grown on the surface of ZIF-67 crystals following thermal activation at 700°C. The resulting PtCo-NCNTs electrocatalysts were deposited on Nafion-212 solid electrolyte membrane by spray technique to study the oxygen reduction reaction (ORR) in the presence of H2/O2 gases in a temperature range of 50-70°C. The present study elucidates the performance of nitrogen-doped carbon nanotubes ORR electrocatalysts derived from ZIF-67 and the effects of membrane electrode assembly (MEA) steaming on the performance of proton exchange membrane fuel cell (PEMFC) employing PtCo-NCNTs as ORR electrocatalysts. We observed that the peak power density at 70°C was 450 mW/cm2 for steamed membrane electrode assembly (MEA) compared to 392 mW/cm2 for an identical MEA without steaming.

Study on the degradation mechanism of the proton exchange membrane fuel cell based on constant voltage cold start mode

2021 ◽  
pp. 1-23
Author(s):  
Yanbo Yang ◽  
Tiancai Ma ◽  
Fenglai Pei ◽  
Weikang Lin ◽  
Kai Wang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
Degradation Mechanism ◽  
Cold Start ◽  
Proton Exchange ◽  
Constant Voltage ◽  
Fuel Cell Performance ◽  
Start Up ◽  
Exchange Membrane

Abstract The constant voltage cold start of the proton exchange membrane fuel cell (PEMFC) is usually operated at a low start voltage in order to ensure high heat generation, which can shorten the process of the PEMFC cold start. However, the effect of constant voltage cold start on the durability of PEMFC is still unclear. Thus, in this work, the PEMFC is tested repeatedly at a low start-voltage to simulate its actual operating state in the vehicle. Then the effect of the PEMFC durability under constant voltage cold start is investigated by polarization curve, cyclic voltammetry, electrochemical impedance spectroscopy, transmission electron microscope and ion chromatography. After the repeatedly cold start, the output performance of the PEMFC decreases significantly. According to the characterization results, the degradation mechanism of the PEMFC at the constant voltage cold start is demonstrated to be that the PEMFC start-up repeatedly at low start-voltage leads to the decomposition of membrane polymer structure and promotes the crossover of H2. Meanwhile, the PEMFC start-up repeatedly at low start-voltage also leads to the agglomeration of catalysts, which reduces the active area of catalysts and ultimately results in the degradation of fuel cell performance. Above all, this study proves that the durability of PEMFC can be shortened by the constant voltage cold start at 0.1 V, which provides a reference for the development of the PEMFC cold start control strategy.

scholarly journals Experimental Study on the Effect of Hydrogen Sulfide on High-Temperature Proton Exchange Membrane Fuel Cells by Using Electrochemical Impedance Spectroscopy

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 441 ◽  
Author(s):  
Ren-Jun Kang ◽  
Yong-Song Chen
Keyword(s):  
Hydrogen Sulfide ◽  
High Temperature ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Cell Performance ◽  
Membrane Electrode ◽  
Pure Hydrogen ◽  
Exchange Membrane

When the fuel supplied to a high-temperature proton exchange membrane fuel cell (HT-PEMFC) is produced by hydrocarbon formation, hydrogen sulfide (H2S) may appear, resulting in decreased cell performance and durability. To study the effects of H2S on the performance and durability of the HT-PEMFC, a series of experiments was conducted. In the first step, the effects of polyvinylidene fluoride (PVDF) and platinum loading on cell performance were investigated and discussed under pure hydrogen operation conditions. Optimal PVDF and platinum compositions in the catalyst layer are suggested. Then, the effect of H2S on membrane electrode assembly (MEA) performance with various platinum loadings was investigated by supplying hydrogen containing 5.2 ppm of H2S to the anode of the MEA. An electrochemical impedance spectroscope was employed to measure the impedance of the MEAs under various operating conditions. Finally, degradation of the MEA when supplied with hydrogen containing 5.2 ppm of H2S was analyzed and discussed. The results suggest that the performance of an MEA with 0.7 mg Pt cm−2 and 10% PVDF can be recovered by supplying pure hydrogen. The rate of voltage decrease is around 300 μV h−1 in the presence of H2S.

Fabrication of Support Tubular Proton Exchange Membrane For Fuel Cell

2006 ◽  
Vol 4 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Ru-Jun Yu ◽  
Guang-Yi Cao ◽  
Xiu-Qing Liu ◽  
Zhong-Fang Li ◽  
Wei Xing ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
Porous Silica ◽  
Membrane Electrode Assembly ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Direct Methanol ◽  
Exchange Membrane

The support tubular proton exchange membranes (STPEMs) were fabricated successfully by impregnating porous silica pipe into a solution of perfluorinated resin. The structures of the inner, outer, and cross section of support PEM tube were characterized intensively by scanning electron microscopy observation. In addition, the conductivity and impermeability were measured by electrochemical impedance spectroscopy (EIS) and the bubble method, respectively. Results show that the conductivity of the PEM can reach as low as 1.46S∕m when using the silica pipe of 0.7mm wall thickness. Subsequently, the ST membrane electrode assembly for direct methanol fuel cell (DMFC) and proton exchange membrane fuel cell (PEMFC) applications was prepared first by loading Pt∕C and Pt–Ru∕C catalyst ink onto the outer and inner surfaces of the PEM tube, respectively. The performances of the tubular DMFC and the PEMFC were tested on a self-made apparatus, which shows that the power density of tubular DMFC can reach 10mWcm−2 when 4molL−1 methanol solution flows through the anode at 80°C, and that the power density of tubular PEMFC can reach up to 60mWcm−2 when hydrogen flows at the rates of 20mlmin−1 through the anode at 60°C, both the cathodes adopting air-breathing mode.

Understanding of Nafion Membrane Additive Behaviors in Proton Exchange Membrane Fuel Cell Conditioning

2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Nana Zhao ◽  
Zhong Xie ◽  
Zhiqing Shi
Keyword(s):  
Fuel Cell ◽  
Large Scale ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Production Volume ◽  
Transfer Resistance ◽  
Conditioning Process ◽  
Exchange Membrane

Durability and cost are the two major factors limiting the large-scale implementation of fuel cell technology for use in commercial, residential, or transportation applications. The conditioning cost is usually negligible for making proton exchange membrane fuel cells (PEMFCs) at R&D or demo stage with several tens of stacks each year. However, with industry's focus shifting from component development to commercial high-volume manufacturing, the conditioning process requires significant additional capital investments and operating costs, thus becomes one of the bottlenecks for PEMFC manufacturing, particularly at a high production volume (>1000 stack/year). To understand the mechanisms behind PEMFC conditioning, and to potentially reduce conditioning time or even to eliminate the conditioning process, the conditioning behaviors of commercial Nafion™ XL100 and Nafion® NRE 211 membranes were studied. The potential effects of the membrane additive on fuel cell conditioning were diagnosed using in situ electrochemical impedance spectroscopy (EIS). It was found that the membrane additive led to the significant variation of the charge transfer resistance in EIS during conditioning, which affected the conditioning behavior of the membrane electrode assembly (MEA).

scholarly journals Monodispersed Pt3Ni Nanoparticles as a Highly Efficient Electrocatalyst for PEMFCs

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 588 ◽  
Author(s):  
Delong Yang ◽  
Jun Gu ◽  
Xiaomeng Liu ◽  
Haitong He ◽  
Meiyu Wang ◽  
...  
Keyword(s):  
Proton Exchange Membrane ◽  
Reduction Process ◽  
Membrane Electrode Assembly ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Electrochemical Surface Area ◽  
Oxygen Reduction Reaction Activity ◽  
Mass Activity ◽  
Exchange Membrane

A facile strategy is proposed to synthesize monodispersed Pt3Ni nanoparticles. Such a kind of electrocatalyst shows a larger electrochemical surface area (98.9 m2 gpt−1) and double the mass activity of the oxygen reduction reaction activity compared to commercial Pt/C catalyst. The results show that the suitable addition of Ni and triethylamine in the reduction process plays an important role in controlling the size and dispersion of Pt3Ni nanoparticles. A further membrane electrode assembly test proves that as-prepared Pt3Ni nanoparticles can greatly enhance the electrochemical performance of a proton exchange membrane fuel cell, which exhibits a great potential of application in fuel cells.

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