A honeycomb-like flow channel was proposed and investigated for the performance of proton exchange membrane fuel cells (PEMFCs). The effects of various thicknesses and porosities of the gas diffusion ...layer (GDL) on the honeycomb-like flow channel were studied. Compared with parallel and serpentine flow channels, the honeycomb-like flow channel exhibited the lowest oxygen non-uniformity value of 0.59 at 0.4 V, and the pressure drop was 6.9 times lower than that of the serpentine flow channel. The current density was 8034.9 A/m2, which was 14.0% and 10.4% higher than that of the parallel and serpentine flow channels. For a porosity of 0.4, the decrease in GDL thickness from 0.58 to 0.38 mm for the honeycomb-like flow channel facilitated oxygen diffusion, and the current density increased from 7717.2 to 8034.9 A/m2; the oxygen mass fraction gradually increased at the cathode channel but decreased at the center of the honeycomb-like structure. At a thickness of 0.38 mm, the porosity increased from 0.2 to 0.6, leading to a decrease in the oxygen non-uniformity value from 0.89 to 0.42. For a porosity of 0.6, the current density was 8787 A/m2, which was 60% and 9.4% greater when compared with the porosities of 0.2 and 0.4.
•The novel honeycomb-like flow channel design was proposed.•The performance improvement of PEMFCs with different flow channels was characterized.•The effect of GDL thickness and porosity for the novel flow channel were studied.
Poly(vinyl alcohol) (PVA) is a biodegradable, water-soluble membrane that has low methanol permeation and reactive chemical functionalities. Modification of these features makes PVA an attractive ...proton exchange membrane (PEM) alternative to Nafion
TM
. However, the pristine PVA membrane is a poorer proton conductor than the Nafion
TM
membrane due to the absence of negatively charged ions. Hence, modification of PVA matrixes whilst complying with the requirements of projected applications has been examined extensively. Generally, three modification methods of PVA membranes have been highlighted in previous reports, and these are (1) grafting copolymerization, (2) physical and chemical crosslinking, and (3) blending of polymers. The use of each modification method in different applications is reviewed in this study. Although the three modification methods can improve PVA membranes, the mixed method of modification provides another attractive approach. This review covers recent studies on PVA-based PEM in different fuel cell applications, including (1) proton-exchange membrane fuel cells and (2) direct-methanol fuel cells. The challenges involved in the use of PVA-based PEM are also presented, and several approaches are proposed for further study.
•Implementation of several ML techniques to investigate performance of degraded FCV.•The Deep Neural Network algorithm has the most accurate prediction among the other.•Dynamic simulation of a fresh ...& degraded FCV considering environmental aspects.•The life cycle assessment for the fresh and degraded fuel cell vehicles.•Using real driving cycle for a better dynamic simulation.
Fuel cell degradation is one of the main challenges of hydrogen fuel cell vehicles, which can be solved by robust prediction techniques like machine learning. In this research, a specific Proton-exchange membrane fuel cell stack is considered, and the experimental data are imported to predict the future behavior of the stack. Besides, four different prediction neural network algorithms are considered, and Deep Neural Network is selected. Furthermore, Simcenter Amesim software is used with the ability of dynamic simulation to calculate real-time fuel consumption, fuel cell degradation, and engine performance. Finally, to better understand how fuel cell degradation affects fuel consumption and life cycle emission, lifecycle assessment as a potential tool is carried out using GREET software. The results show that a degraded Proton-exchange membrane fuel cell stack can result in an increase in fuel consumption by 14.32 % in the New European driving cycle and 13.9 % in the FTP-75 driving cycle. The Life Cycle Assessment analysis results show that fuel cell degradation has a significant effect on fuel consumption and total emission. The results show that a fuel cell with a predicted degradation will emit 26.4 % more CO2 emissions than a Proton-exchange membrane fuel cell without degradation.
Proton exchange membrane water electrolysis (PEMWE) is a key technology for future sustainable energy systems. Proton exchange membrane (PEM) electrolysis cells use iridium, one of the scarcest ...elements on earth, as catalyst for the oxygen evolution reaction. In the present study, the expected iridium demand and potential bottlenecks in the realization of PEMWE for hydrogen production in the targeted GW a−1 scale are assessed in a model built on three pillars: (i) an in-depth analysis of iridium reserves and mine production, (ii) technical prospects for the optimization of PEM water electrolyzers, and (iii) PEMWE installation rates for a market ramp-up and maturation model covering 50 years. As a main result, two necessary preconditions have been identified to meet the immense future iridium demand: first, the dramatic reduction of iridium catalyst loading in PEM electrolysis cells and second, the development of a recycling infrastructure for iridium catalysts with technical end-of-life recycling rates of at least 90%.
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•First feasibility-study on iridium supply and demand for hydrogen economy.•Linking iridium production and recycling with technical prospects for catalyst loading.•Providing a technology specific iridium demand model for PEM water electrolysis.•Scenario analysis of large-scale PEM water electrolysis future market development.
Recent progress on branched polymer membranes as electrolyte materials for proton exchange membrane fuel cell (PEMFC) applications has attracted interest due to the limitations of commercially ...available Nafion® membranes. Branched polymer membranes have shown improved chemical stability, proton conductivity, and good solubility. The branching degree and the structure of the branching agent have an essential correlation with the characteristics of the polymer membranes. This review presents the most recent and promising design strategies and characteristics of branched polymers as proton exchange membranes for both low- and high-temperature proton exchange membrane fuel cells. Recent advances in branched polymers are summarized, including branched sulfonated poly(aryl ether)s, branched sulfonated polyimides, branched polybenzimidazoles, etc. The remaining challenges and prospects in proton exchange membranes are also discussed.
Graphene oxide (GO) contains several chemical functional groups that are attached to the graphite basal plane and can be manipulated to tailor GO for specific applications. It is now revealed that ...the reaction of GO with ozone results in a high level of oxidation, which leads to significantly improved ionic (protonic) conductivity of the GO. Freestanding ozonated GO films were synthesized and used as efficient polymer electrolyte fuel cell membranes. The increase in protonic conductivity of the ozonated GO originates from enhanced proton hopping, which is due to the higher content of oxygenated functional groups in the basal planes and edges of ozonated GO as well as the morphology changes in GO that are caused by ozonation. The results of this study demonstrate that the modification of dispersed GO presents a powerful opportunity for optimizing a nanoscale material for proton‐exchange membranes.
Oxidized: The reaction of graphene oxide (GO) with ozone results in a high level of oxidation that leads to a significantly improved ionic (protonic) conductivity of GO. This effect originates from enhanced proton hopping, which is due to the higher content of oxygenated functional groups in the basal planes and edges of the ozonated GO as well as the morphology changes that are caused by the ozonation.
In this article, a model predictive control (MPC) energy management strategy is proposed to distribute power flows of proton exchange membrane fuel cell (PEMFC)-based hybrid power systems consisting ...of PEMFC, battery, and waste heat recovery system such as TEG and CHP. To optimally meet the demand of load power balancing as well as protect PEMFC from lifetime degradation, a novel objective function by considering fuel consumption, state-of-charge (SOC) of battery, as well as power slope and temperature of PEMFC is constructed and solved in the states prediction horizon within the defined lifetime constraints and SOC limitations. In particular, temperature effects are newly introduced by adding a state-variable to the energy management model and formulating a penalty function. Simulations with mobility and stationary application scenarios are presented. In the automobile case, the hydrogen consumption of the constraints MPC is reduced by 9.98% compared with the rule-based strategy, and the same results can be achieved in the household application. A hardware in the loop experiment was carried out to verify the real-time performance of the MPC strategy which occupied a 2.21% average CPU load rate. The proposed MPC strategy has a promising fuel consumption optimization, lifetime extension, and real-time capability.
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