Fuel Cells最新文献

1T/2H-MoS₂/CdS composite was effectively prepared by a two-step hydrothermal method, which greatly improved the photocatalytic degradation efficiency of tetracycline hydrochloride and photocatalytic cycle stability compared with pristine 1T/2H-MoS₂. The highest photodegradation efficiency of 70.8% is achieved when the molar ratio of 1T/2H-MoS₂ to cadmium sulfide is 1:4. The capture experiment indicates that hydroxyl radical (⋅OH) and superoxide radical (⋅O₂⁻) play a role in the photocatalytic degradation process. A Z-type heterojunction may be formed on the 1T/2H-MoS₂/CdS composite based on a series of analyses, which improves the photocatalytic performance effectively via expanding the range of light response and promoting the separation of photogenerated electrons and holes. This work provides an alternative to constructing novel Z-scheme photocatalysts with high performance in the absence of noble metals.

In this study, Pd/TiO₂ decorated carbon nanofibers (Pd/TiO₂@CNFs) and Pd@CNFs were prepared by the impregnation method for application in direct methanol fuel cells (DMFCs). Pd and TiO₂ particles were supported on the surface of carbon fibers. Noticeably, When the mass fraction of PdCl₂ added is 4%, the Pd@CNFs catalyst (Pd-4@CNFs) showed higher electrocatalytic activity and stability, which were about 28.4 and 13.2 times higher than those of commercial Pd/C catalyst, respectively. On the basis of Pd-4@CNFs catalyst, TiO₂ with a mass fraction of 10% was added to produce Pd/TiO₂@CNFs catalyst (Pd-4/TiO₂-10@CNFs). The electrocatalytic activity of Pd-4/TiO₂-10@CNFs increased to 3,850.4 A·g⁻¹, which was 31.9 times higher than that of commercial Pd/C catalysts. These results demonstrated that the novel Pd/TiO₂@CNFs catalyst is expected to be an efficient and durable catalyst for DMFC.

Bipolar plates are the key component in polymer electrolyte membrane fuel cells (PEMFCs), which ensure the low cost of the fuel cell stack and furnish some of the important applications such as distributing the reactant gases, conducting the electrons, and removing the waste heat in PEMFCs. Thus, metallic bipolar plates (BPs), such as aluminum (Al), have attracted immense consideration and afford better performance in different machine-driven applications and mass manufacturing opportunities. In order to increase the corrosion resistance of Al BPs, several methods are used and conducted by scientists. The corrosion behavior and surface structure analysis of pure Al were studied through the immersion process in fluoride-sulfate solutions, assuming its use as BPs in PEMFC-produced water. The open cell voltage, interfacial contact resistance, and polarization tests and the fuel cell operations were performed to evaluate cell voltage, current density, corrosion resistance, and the effect of fluoride and sulfate ions on the BPs in PEMFC. The hydrophobicity character of the surface of Al BPs was observed by the measurement of the wettability test. The atomic force microscopy images were taken to study the surface roughness, which was correlated with the corrosion rates of Al BPs. In addition, the amount of corrosion was calculated after 24–120 h of immersion in fluoride-sulfate solutions. The scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy data were analyzed to investigate the surface structure, morphology, and elemental analyses. Thus, the results found in this study revealed that Al-based materials can be suitable for BPs in PEMFCs. Furthermore, it is noticed that the amount of corrosion was influenced by the presence of even a very small amount of fluoride ions present in the PEMFC environment, while it was suppressed efficiently by sulfate ions.

The gas diffusion layer (GDL), one of the essential components of the membrane electrode assembly (MEA), plays an important role in the performance of proton exchange membrane fuel cells. With respect to this essential component and its specifications, this work intends to examine the impact of GDL defects and their effects on cell performance for component quality control. To understand how GDL defect affects its performance and to what level the defect takes effect, ex situ characterization and in situ fuel cell testing are conducted by comparing pristine and defective GDLs. While ex situ GDL properties incorporate measurements of thickness, conductivity, and permeability under compression, in situ investigation mainly involves polarization curve and electrochemical impedance spectroscopy. Among different types of GDL defects, pinholes are targeted in this work. As such, the evaluation focuses on assessing the effects of varying numbers and sizes of pinhole defects under different relative humidities (RHs). Using the state-of-the-art GDLs, an improved cell performance is observed with defective GDLs (evenly distributed 40 pinholes with a diameter of 0.58 mm) under 100% RH. Results also show that the effect of pinhole defects is sensitive to RH, as well as operating current densities.

The chemical reactivity between Pr₄Ni₃O_10±δ (3-PNO) electrodes and Y_0.08Zr_0.92O_1.96 (YSZ), Ce_0.9Gd_0.1O_1.95 (GDC), and La_0.9Sr_0.1Ga_0.8Mg_0.2O_2.85 (LSGM) electrolytes was analyzed by electrochemical impedance spectroscopy and X-ray diffraction. 3-PNO powders were synthesized by two different chemical routes, one of them uses hexamethylenetetramine (HMTA) as a complexing agent (route A) while the other citrates (route B). The samples observed by scanning electron microscopy presented different microstructures; route A powders present small submicronic grains with an open microstructure while route B powders are formed by larger well-connected grains. The polarization resistance (R_P) values for 3-PNO/YSZ cells are one order of magnitude higher than those of 3-PNO/GDC and 3-PNO/LSGM cells. The R_P for both cells 3-PNO/GDC and 3-PNO/LSGM and its evolution in time suggest that chemical reactivity takes place during the adhesion treatment and electrochemical measurements. The microstructure plays a crucial role in R_P and the degradation rate; 3-PNO obtained by route A (3-PNO-HMTA) exhibits the best electrochemical performance since these powders present a well-loose morphology and a large exposed area. However, this fact makes them active chemically, so the increase of R_P with time is slower for 3-PNO electrodes prepared by route B (3-PNO-Cit), since the rate of chemical reactivity with the electrolyte is slower.

In the production of catalyst-coated membranes (CCMs) for proton-exchange membrane fuel cells and electrolyzers, the ink formulation and its processing are key factors in determining the resulting catalyst layer. Catalyst inks often contain a multicomponent solvent mixture. Selective drying, which can occur with solvent mixtures, changes the composition in the solidifying film and thus influences the microstructure of the layer that forms. The selectivity depends on the material-specific thermodynamics of the solvents and the process-related drying parameters. Different 1-propanol/water mixtures serve as the state of the art material system considered and commonly used for CCM inks. Typical solvent mixtures can be dried selectively or non-selectively, depending on the initial ink composition and humidity of the drying air. In mixtures that contain more 1-propanol than the azeotropic or arheotropic composition, the 1-propanol content accumulates in the remaining liquid; if there is less, it decreases. Increasing the preloading of the drying air with water leads to a relative water enrichment and shifts the tipping point to higher initial alcohol fractions. This behavior can be transferred to the real CCM production.

In low-temperature environment, the residual water in the membrane electrode assembly (MEA) will freeze after the operation of proton exchange membrane fuel cells, which will cause damage to the MEA. In this paper, the effect of freeze–thaw cycles on MEA was studied. Six sets of MEA samples with 0, 20, 40, 60, 80, and 100 times freeze–thaw cycles were set up, and the damage on MEAs is analyzed by polarization curves, electrochemical impedance spectra, cyclic voltammetry curves, and scanning electron microscope. It was found that the freeze–thaw cycles caused degradation on MEA, and the ohmic resistance of MEA increases with the number of cycles increases before the 60 freeze–thaw cycles, and after 60 freeze–thaw cycles, a gap appeared between the proton exchange membrane (PEM) and the catalyst layer, which led to more water entering the PEM and the ohmic resistance of MEA decreased. Besides, according to the data analysis, the experimental samples are divided into three categories (normal MEA, lightly damaged MEA, and seriously damaged MEA). A classifier model combining inception network and light gradient boosting machine (LGBM) was established, and it was found that the combined model was better than inception–dense and LGBM for classification, reaching 96.89%.

Dear Colleagues,

Welcome to the first issue of Fuel Cells – From Fundamentals to Systems in 2024. With this issue the journal is heading off for volume 24.

We hope this year we can continue to bring more excellent research in electrochemical systems with a full spectrum of special and topical issues planned alongside regular issues.

We are happy to see the improvement of the journal's Impact Factor to 2.95, which is an achievement from the effort of everyone who contributed to the journal. With the expanded scopes for the journal from only fuel cell research to more broad electrochemical systems and fundamentals, we hope to see a steady growth of submission, publication and citations. This has already been shown by a 21% higher submission rate in 2023 than 2022.

As Special Issues (SI) and Topical Issues (TI) have proven as high impact facets of the journal from their start in 2001, and related publications always show up among the top-ten downloaded Fuel Cells – From Fundamentals to Systems articles.

There are few other possible topical issues in planning, including a Virtual Issue to honor Professor Dr. Ulrich Stimming, who stepped down as Editor-in-Chief in July 2023, but will still be an active member of the Editorial Office as Founding Editor.

Thus, we would like to say a special THANK YOU to all the Guest Editors of both Topical and Special Issues, for inviting and taking care of the publication of highest quality articles at the core interests of our readers.

We welcome ideas for Topical Issues to showcase research development in a particular field related to electrochemical processes and systems.

Although we have discovered some delays in the restructuring of the Editorial Office as well as the Editorial Board, let us welcome the new members of the Editorial Board, who joined us in the second half of 2023 and injected new energy and dynamics, as well as expertise to the Editorial Board. We will introduce them in the coming issues. The new members are from diverse geographic and expertise areas. We hope to work together to continue the work started by Prof. Dr. Stimming and enhance the impact of the journal even further.

They will work together with existing Editorial Board Members to serve the community and make some exciting changes.

Nevertheless, besides all efforts from the Editorial Office the future development of the journal will strongly depend on your activity in making the journal known to everybody in our community or by contributing to the journal as guest editors, reviewers or authors.

Thus, we are looking forward to your cooperation for Volume 23, 2024, and to receiving your contributions.

With kind regards,

Fuel Cells – From Fundamentals to Systems publishes on all aspects of fuel cells, ranging from their molecular basis including theory and with molecular processes at catalyst surfaces and microscopic processes in membranes to their application in systems such as power plants, road vehicles and power sources in portables. It includes electrochemical energy technology as in energy conversion and storage with batteries, supercapacitors and electrolytic processes. Fuel Cells is a platform for scientific exchange in a diverse interdisciplinary field. All related work in chemistry, physics, materials science, chemical engineering, electrical engineering, and mechanical engineering is included.

The performance and durability of proton-exchange membrane fuel cells (PEMFCs) are constrained by fuel delivery and water management. Based on parallel and serpentine flow fields, the effects of triangular baffles (30°, 45°, and 60°) and conical runners (1°, 2°, and 3°) on the performance output of PEMFC at different angles are studied. The three-dimensional and multi-phase models are established by using the simulation software package (ANSYS FLUENT). The findings demonstrate that the battery's output performance reaches its peak when the baffle angle is set at 45°. When the output current density is 0.7 A/cm², the power density of the 45° baffle increases by 18.87%. The pressure loss is not only lower than that of the 60° baffle but also exhibits no significant difference when compared to the 30° baffle. In addition, the introduction of conical channels has enhanced the output performance of PEMFCs in comparison to the traditional serpentine flow field. The power density of the 2°tapered channel exhibits a 12.65% increase when the output current density reaches 0.8 A/cm². However, the performance output of the 3°tapered channel is inferior to that of the conventional serpentine flow field.