scholarly journals Study on the Durability of Recast Nafion/Montmorillonite Composite Membranes in Low Humidification Conditions

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
A. Pozio ◽  
A. Cemmi ◽  
F. Mura ◽  
A. Masci ◽  
R. F. Silva
Keyword(s):  
Fuel Cell ◽  
Relative Humidity ◽  
Polymer Membranes ◽  
Composite Membranes ◽  
Polymeric Membrane ◽  
Membrane Degradation

Nafion composite membranes were formed from a recasting procedure previously reported by the authors. Montmorillonite (MMT) was used as a filler in the recasting procedure, and dimethylformamide (DMF) was used as the casting solvent. Fuel cell tests performed with the recast membrane showed that at low relative humidity (R.H.) the conductivity of the MMT-containing membranes is 10% higher than that of the MMT-free samples. In order to investigate the durability of such composite perfluorosulfonate membranes, long-term fuel cell experiments have been carried out. Results evidenced a strong effect of low RH on the lifetime of commercial polymer membranes, but the addition of a small silicate amount to the polymeric membrane reduced strongly the membrane degradation.

Evaluation of a ZrO2 Composite Membrane in PEM Fuel Cells Operating at High Temperature and Low Relative Humidity

2011 ◽  
Vol 14 (2) ◽  
pp. 93-98
Author(s):  
C. Guzman ◽  
A. Alvarez ◽  
Luis A. Godinez ◽  
O. E. Herrera ◽  
W. Merida ◽  
...  
Keyword(s):  
High Temperature ◽  
Fuel Cell ◽  
Relative Humidity ◽  
Composite Membrane ◽  
Water Flux ◽  
Composite Membranes ◽  
Pem Fuel Cells ◽  
Operation Conditions ◽  
Dipole Interactions ◽  
Performance Results

A composite membrane containing ZrO2 was tested under simulated and real fuel cell operations. To simulate the fuel cell environment, the composite membrane was tested on a gated cell at low relative humidity (10 %) and high temperature (100 °C). The water flux on the composite membrane was found to be higher than a commercial membrane (Nafion 115), suggesting that under these conditions water molecules are entrapped into the membrane matrix via dipole – dipole interactions. Under real operation conditions, ZrO2 membranes showed better performance at high temperature (140 °C) and low relative humidity (22.9 %) than the commercial Nafion Membrane. The performance results confirmed that composite membranes retain water and help to maintain the membrane hydration. The aging cycle (1750 cycles) showed that the composite membrane under study is stable under extreme operation conditions (22.9% RH and 120 °C).

scholarly journals Review of the Durability of Polymer Electrolyte Membrane Fuel Cell in Long-Term Operation: Main Influencing Parameters and Testing Protocols

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4048
Author(s):  
Huu Linh Nguyen ◽  
Jeasu Han ◽  
Xuan Linh Nguyen ◽  
Sangseok Yu ◽  
Young-Mo Goo ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Failure Modes ◽  
Polymer Electrolyte Membrane ◽  
Durability Test ◽  
Term Operation ◽  
Electrolyte Membrane ◽  
Transportation Applications ◽  
Testing Protocols

Durability is the most pressing issue preventing the efficient commercialization of polymer electrolyte membrane fuel cell (PEMFC) stationary and transportation applications. A big barrier to overcoming the durability limitations is gaining a better understanding of failure modes for user profiles. In addition, durability test protocols for determining the lifetime of PEMFCs are important factors in the development of the technology. These methods are designed to gather enough data about the cell/stack to understand its efficiency and durability without causing it to fail. They also provide some indication of the cell/stack’s age in terms of changes in performance over time. Based on a study of the literature, the fundamental factors influencing PEMFC long-term durability and the durability test protocols for both PEMFC stationary and transportation applications were discussed and outlined in depth in this review. This brief analysis should provide engineers and researchers with a fast overview as well as a useful toolbox for investigating PEMFC durability issues.

scholarly journals Microstructure Evolution in a Solid Oxide Fuel Cell Stack Quantified with Interfacial Free Energy

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3476
Author(s):  
Tomasz A. Prokop ◽  
Grzegorz Brus ◽  
Janusz S. Szmyd
Keyword(s):  
Free Energy ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Microstructure Evolution ◽  
Ion Beam ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Long Term Performance ◽  
Term Performance

Degradation of electrode microstructure is one of the key factors affecting long term performance of Solid Oxide Fuel Cell systems. Evolution of a multiphase system can be described quantitatively by the change in its interfacial energy. In this paper, we discuss free energy of a microstructure to showcase the anisotropy of its evolution during a long-term performance experiment involving an SOFC stack. Ginzburg Landau type functional is used to compute the free energy, using diffuse phase distributions based on Focused Ion Beam Scanning Electron Microscopy images of samples taken from nine different sites within the stack. It is shown that the rate of microstructure evolution differs depending on the position within the stack, similar to phase anisotropy. However, the computed spatial relation does not correlate with the observed distribution of temperature.

Analysis of Long-Term and Thermal Cycling Tests for a Commercial Solid Oxide Fuel Cell

2017 ◽  
Vol 14 (4) ◽  
Author(s):  
Dustin Lee ◽  
Jing-Kai Lin ◽  
Chun-Huang Tsai ◽  
Szu-Han Wu ◽  
Yung-Neng Cheng ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Thermal Cycling ◽  
Solid Oxide Fuel Cell ◽  
Coefficient Of Thermal Expansion ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Flow Rates ◽  
Degradation Rates ◽  
Two Stages

The effects of isothermally long-term and thermal cycling tests on the performance of an ASC type commercial solid oxide fuel cell (SOFC) have been investigated. For the long-term test, the cells were tested over 5000 h in two stages, the first 3000 h and the followed 2000 h, under the different flow rates of hydrogen and air. Regarding the thermal cycling test, 60 cycles in total were also divided into two sections, the temperature ranges of 700 °C to 250 °C and 700 °C to 50 °C were applied for the every single cycle of first 30 cycles and the later 30 cycles, respectively. The results of long-term test show that the average degradation rates for the cell in the first 3000 h and the followed 2000 h under different flow rates of fuel and air are 1.16 and 2.64%/kh, respectively. However, there is only a degradation of 6.6% in voltage for the cell after 60 thermal cycling tests. In addition, it is found that many pores formed in the anode of the cell which caused by the agglomeration of Ni after long-term test. In contrast, the vertical cracks penetrating through the cathode of the cell and the in-plane cracks between the cathode and barrier layer of the cell formed due to the coefficient of thermal expansion (CTE) mismatch after 60 thermal cycling tests.

scholarly journals Experimental investigation on water-injected twin-screw compressor for fuel cell humidification

2012 ◽  
Vol 226 (12) ◽  
pp. 2925-2932 ◽  
Author(s):  
Talal Ous ◽  
Elvedin Mujic ◽  
Nikola Stosic
Keyword(s):  
Fuel Cell ◽  
Relative Humidity ◽  
Constant Pressure ◽  
Water Injection ◽  
Injection Rate ◽  
Fuel Cell Stack ◽  
Balance Of Plant ◽  
Air Supply ◽  
Twin Screw ◽  
Mass Flow Rates

Water injection in twin-screw compressors was examined in order to develop effective humidification and cooling schemes for fuel cell stacks as well as cooling for compressors. The temperature and the relative humidity of the air at suction and exhaust of the compressor were monitored under constant pressure and water injection rate and at variable compressor operating speeds. The experimental results showed that the relative humidity of the outlet air was increased by the water injection. The injection tends to have more effect on humidity at low operating speeds/mass flow rates. Further humidification can be achieved at higher speeds as a higher evaporation rate becomes available. It was also found that the rate of power produced by the fuel cell stack was higher than the rate used to run the compressor for the same amount of air supplied. The efficiency of the balance of plant was, therefore, higher when more air is delivered to the stack. However, this increase in the air supply needs additional subsystems for further humidification/cooling of the balance-of-plant system.

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