scholarly journals Lifetime of Catalyst under Voltage Cycling in Polymer Electrolyte Fuel Cell Due to Platinum Oxidation and Dissolution

Technologies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 80
Author(s):  
Victor A. Kovtunenko ◽  
Larisa Karpenko-Jereb
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Platinum Catalyst ◽  
Polymer Electrolyte Membrane ◽  
Reaction Diffusion ◽  
Operating Conditions ◽  
Polymer Electrolyte Fuel Cell ◽  
Stress Tests ◽  
One Dimensional ◽  
Electrolyte Membrane

The durability of a platinum catalyst in a polymer electrolyte membrane fuel cell is studied at various operating conditions with respect to the different electric potential difference (called voltage) applied in accelerated stress tests. The electrochemical reactions of Pt ion dissolution and Pt oxide coverage of the catalyst lead to the degradation of platinum described by a one-dimensional Holby–Morgan model. The theoretical study of the underlying reaction–diffusion system with the nonlinear reactions is presented by numerical simulations which allow to predict a lifetime of the catalyst under applied voltage cycling. The computer simulation investigates how the Pt mass loss depends on the voltage slope and the upper potential level in cycles.

Sensitivity of Thermal Transport and Phase-Change in Thin Porous Layers to the Distribution of the Solid Matrix

2013 ◽  
Author(s):  
Vinaykumar Konduru ◽  
Ezequiel Medici ◽  
Jeffrey S. Allen
Keyword(s):  
Fuel Cell ◽  
Mass Transport ◽  
Polymer Electrolyte ◽  
Solid Phase ◽  
Polymer Electrolyte Membrane ◽  
Operating Conditions ◽  
Transport Layer ◽  
Solid Matrix ◽  
High Water Content ◽  
Electrolyte Membrane

Understanding the water transport in the Porous Transport Layer (PTL) is important to improve the operational performance of polymer electrolyte membrane fuel cells (PEMFC). High water content in the PTL and flow channel decreases the transport of the gas reactants to the polymer electrolyte membrane. Dry operating conditions result in increased ohmic resistance of the polymer electrolyte membrane. Both cases result in decreased fuel cell performance. Multi-phase flow in the PTL of the fuel cell is simulated as a network of pores surrounded by the solid material. The pore-phase and the solid-phase of the PTL are generated by varying the parameters of the Weibull distribution function. In the network model, the mass transfer takes place in the pore-phase and the bulk heat transfer takes place in the both the solid-phase and liquid phase of the PTL. Previous studies have looked at the thermal and mass transport in the porous media considering the pore size distribution. In the present study, the sensitivity of the thermal and mass transport to the different arrangements of the solid-phase is carried out and the effect of different solid-phase distributions on the thermal and liquid transport in PTL of PEM fuel cell are discussed.

scholarly journals Impact of MPL on Temperature Distribution in Single Polymer Electrolyte Fuel Cell with Various Thicknesses of Polymer Electrolyte Membrane

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2499
Author(s):  
Akira Nishimura ◽  
Tatsuya Okado ◽  
Yuya Kojima ◽  
Masafumi Hirota ◽  
Eric Hu
Keyword(s):  
Power Generation ◽  
Fuel Cell ◽  
Temperature Distribution ◽  
Polymer Electrolyte ◽  
Polymer Electrolyte Membrane ◽  
Polymer Electrolyte Fuel Cell ◽  
Electrolyte Membrane ◽  
The Impact ◽  
Plane Temperature ◽  
Power Generation Performance

The impact of micro porous layer (MPL) with various thicknesses of polymer electrolyte membrane (PEM) on heat and mass transfer characteristics, as well as power generation performance of Polymer Electrolyte Fuel Cell (PEFC), is investigated. The in-plane temperature distribution on cathode separator back is also measured by thermocamera. It has been found that the power generation performance is improved by the addition of MPL, especially at higher current density condition irrespective of initial temperature of cell (Tini) and relative humidity condition. However, the improvement is not obvious when the thin PEM (Nafion NRE-211; thickness of 25 μm) is used. The increase in temperature from inlet to outlet without MPL is large compared to that with MPL when using thick PEM, while the difference between without MPL and with MPL is small when using thin PEM. It has been confirmed that the addition of MPL is effective for the improvement of power generation performance of single PEFC operated at higher temperatures than normal. However, the in-plane temperature distribution with MPL is not even.

The Effect of Ionomer Thin Films in Ionomer- and Water-Filled Agglomerate Models

2011 ◽  
Author(s):  
Peter Dobson ◽  
Marc Secanell
Keyword(s):  
Thin Film ◽  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Numerical Models ◽  
Polymer Electrolyte Membrane ◽  
Catalyst Support ◽  
Catalyst Layer ◽  
Polymer Electrolyte Fuel Cell ◽  
Electrolyte Membrane ◽  
Perfluorosulfonated Ionomer

The catalyst layer of a polymer electrolyte fuel cell is commonly represented in mathematical models as an agglomerate structure of carbon catalyst-support particles. There are two prevailing assumptions for the structure of the agglomerates. The first is that the pores are filled with perfluorosulfonated-ionomer (PFSI). The second is that the pores are hydrophilic and are flooded only with liquid water during operation. The objective of this work is to develop numerical models for single water-filled and ionomer-filled agglomerates in a cathode catalyst layer of a polymer electrolyte membrane fuel cell (PEMFC), and investigate the properties of oxygen transport, proton transport, and reaction kinetics. The two models provide different solutions for the distribution of oxygen and protons, and produce a different reaction profile within the agglomerate. Previous numerical water-filled ionomer models in the literature have neglected the effect of the ionomer thin film. Therefore, the results obtained for both ionomer and water-filled models could not be easily compared. In this article, the equations developed relate the assumed structure of the agglomerates to the structure of the catalyst layer (CL). Results compare the effect of the thin film thickness in the two different types of agglomerates and relate the phenomena occurring within the agglomerates to overall catalyst layer performance.

Effect of Operating Conditions on the Water Transport Phenomena at the Cathode of Polymer Electrolyte Membrane Fuel Cell

2009 ◽  
Author(s):  
Sang Hern Seo ◽  
Chang Sik Lee
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Water Transport ◽  
Flow Rate ◽  
Water Droplet ◽  
Polymer Electrolyte Membrane ◽  
Transport Phenomena ◽  
Operating Conditions ◽  
Water Flooding ◽  
Electrolyte Membrane

Water management is very important for polymer electrolyte membrane fuel cell because the fuel cell performance is decreased by flooding phenomena generated by liquid water in the cathode channels. In addition, the proton conductivity and water transport of membrane could become different by hydration contents of membrane. This study is observed water transport phenomena of cathode channels with a polymer electrolyte membrane fuel cell according to various operating conditions. In order to obtain the water images, the transparent fuel cell consists of polycarbonate window of the cathode end plate and gold coated stainless steel as the flow field and current collector of the cathode. To investigate the effects of operating conditions on the water transport, experiments were conducted under various operating conditions such as cell temperature, cathode flow rate and cathode backpressure. As operating time elapsed, it is observed that the water droplet formation, growth, coalescence and removal occurred in the cathode channel. It can be known that the high cathode flow rate prevents water flooding by removal of water in the cathode flow channel. Also, the quantity of water droplet was increased by the high cathode backpressure.

Current Distribution in a Polymer Electrolyte Membrane Fuel Cell Under Flooding Conditions

2009 ◽  
Author(s):  
A. Jamekhorshid ◽  
G. Karimi ◽  
X. Li
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Current Distribution ◽  
Current Density ◽  
Polymer Electrolyte Membrane ◽  
Operating Conditions ◽  
Average Current Density ◽  
Electrolyte Membrane ◽  
Wide Range ◽  
Average Current

Non-uniform current distribution in polymer electrolyte membrane fuel cells results in local over-heating, accelerated ageing, and lower power output than expected. This issue is very critical when fuel cell experiences water flooding. In this work, the performance of a PEM fuel cell is investigated under cathode flooding conditions. A partially flooded GDL model is proposed to study local current density distributions along flow fields over a wide range of cell operating conditions. The model results show as cathode inlet humidity and/or cell pressure increase the average current density for the unflooded portions of the cell increases but the system becomes more sensitive to flooding. Operating the cell at higher temperatures would lead to higher average current densities and the chance of system being flooded is reduced. In addition, higher cathode stoichiometries prevent system flooding but the average current density remains almost constant.

scholarly journals Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Viktor Johánek ◽  
Anna Ostroverkh ◽  
Roman Fiala ◽  
Andrii Rednyk ◽  
Vladimír Matolín
Keyword(s):  
Mass Spectrometry ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Polymer Electrolyte Membrane ◽  
Operating Conditions ◽  
Cell Potential ◽  
Electrolyte Membrane ◽  
Power Load ◽  
Wide Range

The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions.

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