Article
Chemistry, Physical
I. Elferjani, G. Serre, B. Ter-Ovanessian, B. Normand
Summary: The study investigates the chemical degradation of the Nafion membrane by the Fenton mechanism, exploring the influence of ferrous ions Fe2+ on the membrane's degradation and the transport of ionic species between bipolar plates and the membrane. The coupled degradation model is implemented in a PEMFC performance simulator for simulating the degradation process during NEDC.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Physical
Jing Liu, Yan Yin, Junfeng Zhang, Tong Zhang, Xiaojie Zhang, Huicui Chen
Summary: This study investigates the impact of relative humidity cycling on the microstructure changes in the catalyst layer of polymer electrolyte membrane fuel cells, leading to performance degradation. It is found that the growth of Pt/C agglomerate size and residual plastic strain due to swelling/shrinking behavior may cause interfacial delamination between the ionomer and Pt/C agglomerates. Further research is conducted on mathematical modeling and mechanism analysis based on finite element method.
JOURNAL OF POWER SOURCES
(2021)
Article
Materials Science, Multidisciplinary
Qianyun Tan, Yanli Wang
Summary: This study developed Ti4O7 doped polypyrrole coatings on metallic bipolar plates using electrodeposition technique, which showed high chemical stability and good electrical conductivity.
Article
Chemistry, Physical
Hossein Talebi-Ghadikolaee, Mohammad Mahdi Barzegari, Shahaboddin Seddighi
Summary: The study investigates the formation of metallic bipolar plates using 316 stainless steel sheet with a parallel serpentine flow field. The plastic deformation of microchannels, forming limit criteria, and deformation mechanics during the process are explored to establish a reliable fracture initiation model. Experimental stamping tests and finite element simulations are conducted, showing good agreement with thickness distribution and force-displacement curves. A fracture model based on thinning percentage and equivalent strain is developed to predict the instability of metallic bipolar plates.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Polymer Science
Lise Leroy, Gregory Stoclet, Jean-Marc Lefebvre, Valerie Gaucher
Summary: This study aimed to understand and explain the influence of temperature and humidity on the mechanical behavior of thermoplastic starch (TPS). DMA experiments revealed that water molecules reduce the intermolecular hydrogen bond density and result in a less dense entanglement network. In-situ X-ray characterization during starch hydration showed structural changes attributed to conformational changes in the starch chain due to interaction with water molecules. Finally, the mechanical behavior of TPS could be rationalized by considering the Delta T parameter, which corresponds to the temperature difference between the drawing temperature and the glass transition temperature of TPS.
Article
Chemistry, Physical
Huanming Li, Feifei Bi, Liang Dong, Zhutian Xu, Xiaobo Li, Fei Zhou, Chenyao Fan, Weiyu Shi, Linfa Peng, Xinmin Lai
Summary: Proton exchange membrane fuel cells (PEMFCs) are considered promising energy devices for transportation due to their efficiency and cleanliness. However, metallic bipolar plates (BPPs) face a durability problem. Currently, the lack of scientific, efficient, and low-cost evaluation methods limits the development of metallic BPPs. We propose a novel ex-situ accelerated durability evaluation method based on quantitative analysis of voltage loss and metal ions released from metallic BPPs. The method's availability and accuracy were verified through comparison of microstructures after in-situ and ex-situ testing. This method is of great significance for developing metallic BPPs with higher durability.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Physical
F. Ahmadi Khatir, M. M. Barzegari, H. Talebi-Ghadikolaee, S. Seddighi
Summary: Bipolar plates play a crucial role in fuel cells, and this study mainly focuses on the manufacturing process of metallic bipolar plates and the influence of geometric parameters on the plate formation. Experimental results indicate that channel depth, draft angle, and corner radius have the most significant effect on plate thinning, while corner radius and draft angle have the greatest impact on maximum channel depth.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Physical
Shahaboddin Seddighi, Mohammad Mahdi Barzegari, Hossein Talebi-Ghadikolaee
Summary: Stamped metallic bipolar plates made of 0.1mm 304 stainless steel were investigated in this research. The effects of using rubber blank holders on wrinkle reduction were studied, and the optimal assembly path for wrinkle reduction was determined.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Chemistry, Physical
Linfa Peng, Yue Wan, Diankai Qiu, Peiyun Yi, Xinmin Lai
Summary: This study aims to develop a tolerance design method for dimensional and assembly errors on metallic bipolar plates using a contact behavior model. Results show that dimensional and assembly errors lead to uneven pressure distribution, higher contact resistance, and increased GDL porosity. Recommended acceptable maximum dimensional errors and assembly errors for fuel cells with channel widths of 1.0, 2.0, and 4.0 mm are specified.
JOURNAL OF POWER SOURCES
(2021)
Article
Mechanics
Zhenyu Qiu, Wenli Zhu, Hualin Fan
Summary: This research investigated the bending behaviors and fracture mechanics of parallel bamboo strand lumber (PBSL) plates, revealing the impact of orthotropic mechanical behavior on the failure process. The study proposed an orthotropic bamboo plate theory and a composite failure theory to predict deformation, internal forces, stresses, strains, cracking load, and ultimate load of PBSL plates, making significant progress in promoting their application in structural engineering.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Engineering, Manufacturing
Peng Zhang, Michael P. Pereira, Bernard F. Rolfe, Daniel E. Wilkosz, Peter Hodgson, Matthias Weiss
Summary: This study experimentally investigates the brittleness of stainless steel sheets in micro-stamping processes and develops a 2D finite element model to accurately represent material thinning and forming limits. The results suggest that material failure in micro-channel stamping can be successfully assessed by the Forming Limit Diagram (FLD).
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Chemistry, Applied
Yahui Sun, Chaoqun Hu, Jincan Cui, Shuling Shen, Hanxun Qiu, Jing Li
Summary: BSA-modified GO is used to reinforce PPY coatings, resulting in improved performance and corrosion resistance.
PROGRESS IN ORGANIC COATINGS
(2022)
Review
Chemistry, Multidisciplinary
Gaoyang Liu, Faguo Hou, Xindong Wang, Baizeng Fang
Summary: Proton exchange membrane water electrolysis (PEMWE) is a green hydrogen production technology with great potential. Metal-based bipolar plates (BPs), such as stainless steel and titanium, have received significant attention due to their high corrosion resistance and low resistivity. However, these BPs still face challenges like oxidation and hydrogen embrittlement, affecting the performance of PEMWE. Surface modifications, including silane treatment, conductive polymers (e.g., polyaniline and polypyrrole), and nanoparticles-promoted polymer hybrid coatings, have been extensively studied to address these issues. Nanoparticle-promoted polymer hybrid coatings, in particular, offer enhanced corrosion resistance, durability, and conductivity, making them a promising choice for extending the service life of PEMWE.
APPLIED SCIENCES-BASEL
(2023)
Article
Energy & Fuels
Chien-Ju Hung, Wei-Jen Chen, Chao-An Lin, Huan-Ruei Shiu, Bin-Hao Chen
Summary: This study examines the effects of compression, deformation, and contact area in the membrane electrode assembly (MEA) and considers the electrical impedance of fuel cell stacks due to the assembly of metallic bipolar plates. It suggests that an increase in compression force can improve contact resistance, but excessive compression may lead to extra contact resistance and damage to the MEA structure. By proposing different fillet radii metallic bipolar plates, the study found that an appropriate fillet radius can reduce contact resistance by 13% and prevent the accumulation of compression, thus maintaining contact resistance at adequate levels. The current design offers a simple and effective method to minimize dimension tolerance of single fuel cell units and support sufficient compression.
Article
Nuclear Science & Technology
I. Shchemerov, S. A. Legotin, P. B. Lagov, Y. S. Pavlov, K. Tapero, A. S. Petrov, A. Sidelev, V. S. Stolbunov, T. Kulevoy, M. E. Letovaltseva, V. N. Murashev, M. P. Konovalov, V. N. Kirilov
Summary: The sensitivity of polymer-based capacitive relative humidity (RH) sensors after irradiation with neutrons, electrons, and protons was measured. The degradation of the sensors results in a decrease in the upper limit of measurable RH values, while the sensitivity to low RH levels remains stable. Annealing can partially restore the performance of the sensors, indicating a higher radiation sensitivity of the internal circuit compared to the RH-sensing polymer film.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2022)
Article
Electrochemistry
Wenqing Liu, Diankai Qiu, Linfa Peng, Xinmin Lai
Summary: The mechanical degradation of the proton exchange membrane fuel cells usually occurs at a specific local position due to nonuniform hygrothermal conditions. This study systematically investigated the effects of varying temperatures, relative humidity, and gas flow directions on the membrane stress/strain by imposing uneven temperature and water profiles. The results showed that nonuniform temperature and water content significantly affect the membrane response.