Developing a new strategy to retain phosphoric acid (PA) to improve the performance and durability of high‐temperature proton exchange membrane fuel cell (HT‐PEMFC) remains a challenge. Here, a ...strategy for ion‐restricted catcher microstructure that incorporates PA‐doped multi‐quaternized poly(fluorene alkylene‐co‐biphenyl alkylene) (PFBA) bearing confined nanochannels is reported. Dynamic analysis reveals strong interaction between side chains and PA molecules, confirming that the microstructure can improve PA retention. The PFBA linked with triquaternary ammonium side chain (PFBA‐tQA) shows the highest PA retention rate of 95%. Its H2/O2 fuel cell operates within 0.6% voltage decay at 160 °C/0% RH, and it also runs over 100 h at 100 °C/49% RH under external humidification. This combination of high PA retention, and chemical and dimensional stability fills a gap in the HT‐PEMFC field, which requires strict moisture control at 90–120 °C to prevent acid leaching, simplifying the start‐up procedure of HT‐PEMFC without preheating.
With the cooperation of ion pair interaction for multi‐quaternized side chains with phosphoric acid (PA) and microstructure with nanochannels, the PFBA‐tQA tends to form ion‐restricted catcher microstructure, which efficiently improves PA retention under an external humidity environment. It can utilize water to promote ion conduction without PA loss and possesses grant advantages for fuel cells when worked under medium and high‐temperature regions.
A novel low cost proton exchange membrane (PEM) was synthesized, using biochar derived from food waste by pyrolysis at 600 °C followed by sulphonation and using a poly vinyl alcohol based matrix, ...named as SBC-600, for application in microbial fuel cell (MFC). Membrane properties such as proton conductivity, ion transport number and oxygen diffusion coefficient were estimated and found to be 0.07 S cm−1, 0.891 and 6.46 × 10−9 m2 s−1, respectively. Proton conductivity per unit cost of SBC-600 membrane (0.42 S cm−1 $−1) was found to be 32 times higher than the Nafion membrane. The MFCs with SBC-600 membrane (MFC-SBC) and Nafion 117 as PEM (MFC-N) exhibited chemical oxygen demand removal efficiencies of 81 ± 6.6% and 88 ± 4.9%, respectively. Power harvested per unit cost of membrane was 26 times higher for MFC-SBC (0.278 W $−1) than MFC-N (0.011 W $−1) offering a low cost alternative to the costly PEM presently used in MFCs for its field scale applications.
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•Sulphonated biochar used as a novel proton exchange membrane in MFC.•Cost of sulphonated membrane was found to be hundred fold lesser than Nafion.•Power achieved per unit cost using biochar membrane was 26 times higher than Nafion.•Sulphonation introduced –SO3H groups on biochar scaffold to enhance cation exchange.
Proton Exchange Membrane Fuel Cells (PEMFC) are energy efficient and environmentally friendly alternatives to conventional energy conversion systems in many yet emerging applications. In order to ...enable prediction of their performance and durability, it is crucial to gain a deeper understanding of the relevant operation phenomena, e.g., electrochemistry, transport phenomena, thermodynamics as well as the mechanisms leading to the degradation of cell components. Achieving the goal of providing predictive tools to model PEMFC performance, durability and degradation is a challenging task requiring the development of detailed and realistic models reaching from the atomic/molecular scale over the meso scale of structures and materials up to components, stack and system level. In addition an appropriate way of coupling the different scales is required.
This review provides a comprehensive overview of the state of the art in modeling of PEMFC, covering all relevant scales from atomistic up to system level as well as the coupling between these scales. Furthermore, it focuses on the modeling of PEMFC degradation mechanisms and on the coupling between performance and degradation models.
•We review PEMFC models ranging from the atomistic scale up to the system level.•We review multiscale approaches for the coupling between the scales.•We review degradation models for all PEMFC components.•Advantages, drawbacks and open issues of the models are discussed.
•Electrochemical and heat transfer analyses of proton exchange membrane fuel cell.•Introducing a new design using porous media inside the gas flow channel.•Evaluating the power density, voltage, ...pressure drop and Nu as the outputs.•Define a new parameter “Evaluation Criterion of Proton Exchange Membrane (ECPEM)”.•Training an ANN model to calculate the optimum value of ECPEM to be 78.88.
The focus of this study is to evaluate the effects of porous media inside the gas flow channel of Proton Exchange Membrane Fuel Cells (PEMFC) on four different output parameters of voltage, power density, pressure drop, and Nusselt number (Nu) considering the impacts of its thickness, viscous resistance, and current density. Although it is proved that the new design will improve the convective heat transfer, there have not been studies to evaluate the effects of this porous layer on the electrochemical performance and heat transfer simultaneously. The results showed that viscous resistance has by far the highest impact on the power densities in high current densities while thicker inserted porous layer improves the performance. Results also demonstrate that a parameter is needed to consider all these output parameters at the same time, hence the Evaluation Criterion of Proton Exchange Membrane (ECPEM) is defined using artificial neural network (ANN) modeling. Single-objective optimization of the ECPEM is developed using the ANN models to produce 250,000 data. The optimum value of ECPEM was obtained 78.88 in the thickness of 500 μm and the viscous resistance of 2,111,000 (1m2) while the current density is equal to 0.65 (A/cm2).
The high-temperature proton exchange membrane fuel cell (HT-PEMFC) offers several advantages, such as high proton conductivity, high CO tolerance, good chemical/thermal stability, good mechanical ...properties, and low cost. The proton exchange membrane (PEM) is the critical component of HT-PEMFC. This work discusses the methods of current PEMs development for HT-PEMFC including modifications of Nafion® membranes and the advancement in composite PEMs based on non-fluorinated polymers. The modified Nafion®-based membranes can be used at temperatures up to 140 °C. Nevertheless, the application of Nafion®-based membranes is limited by their humidification with water molecules acting as proton carriers and, thus, by the operation conditions of membranes under a relative humidity below 20%. To obtain PEMs applied at higher temperatures under non-humidified conditions, phosphoric acid (PA) or ionic liquids (ILs) are used as proton carriers in PEMs based on non-fluorinated polymers. The research discussed in this work provides the approaches to improving the physicochemical properties and performance fuel cell of PEMs. The effects of polymer blending, crosslinking, and the incorporation of inorganic particles on the membrane properties and fuel cell performance have been scrutinized. The incorporation of inorganic particles modified with ILs might be an effective approach to designing high-performance PEMs for HT-PEMFC.
Although widely used as proton-exchange membranes (PEMs), perfluorosulfonic acid (PFSA) membranes suffer from critical mechanical degradation under alternating wet/dry conditions. A common method for ...improving the mechanical durability of PFSA membranes is to intercalate single-layer expanded polytetrafluoroethylene (ePTFE). As reinforcement skeletons, the different numbers of ePTFE layers can be expected to have different effects on the mechanical durability of PFSA-based PEMs. In this study, double layers of ePTFE reinforcement are intercalated into PFSA ionomer to further enhance the mechanical durability of such membranes. The mechanical strength in directions A and B of the double-layer ePTFE reinforced membrane (DR-M) are 36.52 and 37.12 MPa, which are significantly higher than those (24.37 and 27.51 MPa) of the single-layer ePTFE reinforced membrane (SR-M). The area swelling rate of the DR-M is 11.91%, which is lower than that (15.53%) of SR-M. It is precisely due to the additional rigid ePTFE skeleton for the DR-M that the yield strength and modulus of the PFSA membrane are further improved, resulting in the higher resistance to plastic deformation. After 3000 cycles of alternating wet/dry conditions, DR-Ms exhibited no significant hydrogen crossover current increase (from 3.01 mA cm−2 to 2.98 mA cm−2), reduced H2/Air fuel cell performance attenuation (by 4.9%), smaller membrane impedance increase (by 6.2%), and reduced membrane structure failure (less cracks) compared with SR-Ms. In short, the described double-layer ePTFE enhancement strategy provided a fresh perspective for improving the mechanical durability of PEMs.
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•Single-layer and double-layer ePTFE reinforced membranes are prepared.•Double-layer ePTFE reinforcement strategy provides superior dimensional stability.•Double-layer ePTFE reinforcement strategy significantly reduces H2 permeation.•Double-layer ePTFE reinforced membranes show superior mechanical durability.
While proton exchange membrane fuel cells (PEMFCs) continue to expand into commercial markets, there is still pressure to decrease cost. One of the largest opportunities to reducing cost is to reduce ...the amount of platinum‐group metal (PGM) catalysts used in the electrodes (particularly the cathode). Over the past decade, exciting advances in the Fe/N/C family of PGM‐free oxygen reduction reaction (ORR) catalysts has provided great optimism that not only can PGMs at the cathode be reduced but possibly be completely eliminated. In fact, in September 2017, Ballard Power Systems announced the commercialization of the world's first PEMFC product to utilize a PGM‐free catalyst at the cathode (FCgen‐micro (non‐precious‐metal catalyst, NPMC)). However, for these catalysts to be used in more demanding applications, an improved understanding and new design approaches for PGM‐free catalyst layers will be required. Herein, some of the latest research on both modeling and experimental studies in the field of PGM‐free catalyst layer research are discussed. In addition, a short discussion on Ballard's new NPMC is provided.
In late 2017, Ballard and Nisshinbo commercialized the world's first proton exchange membrane fuel cell stack to use a platinum‐group‐metal (PGM)‐free catalyst at the cathode (FCgen‐micro (non‐precious‐metal catalyst)). Some of the key catalyst layer research that has enabled this achievement is summarized, along with a brief description of the stack's performance, durability, and stability.
In this paper, a recent optimization algorithm named multi-verse optimizer (MVO) is applied to identify the optimal parameters of the proton exchange membrane fuel cell (PEMFC) under certain ...operating conditions. Seven parameters to be optimized are ξ1, ξ2, ξ3, ξ4, λ, Rc, b in order to obtain polarization curves closely converged to those obtained in the manufacture’s datasheet. MVO is characterized by simple construction, less controlling parameters and requiring less effort in computation process. Four sets of experimental voltage stack are taken into consideration; two of them are used for optimization process while the others are used for model validation in the presence of two types of parameter constraints. Comparative studies including statistical parameters with two types of methods are performed; the first methods are reported in the literature like SGA, HGA, HABC, RGA and HADE while the second approaches are programmed such as grey wolf optimizer (GWO), artificial bee colony (ABC), mine blast algorithm (MBA) and flower pollination algorithm (FPA). The obtained results reveal that MVO is the best choice among the others since it presents less fitness function and less convergence time.
•Multi-verse optimizer (MVO) is applied to identify the optimal parameters of PEMFC.•Four sets of experimental voltage stack are taken into consideration; for optimization and validation processes.•Four different algorithms GWO, ABC, MBA and FPA are programmed and compared with MVO.•The obtained results reveal that MVO is the best choice among the others.
Applying prognostics to Proton Exchange Membrane Fuel Cell (PEMFC) stacks is a good solution to help taking actions extending their lifetime. However, it requires a great understanding of the ...degradation mechanisms and failures occurring within the stack. This task is not simple when applied to a PEMFC due to the different levels (stack - cells - components), the different scales and the multiple causes that lead to degradation. To overcome this problem, this work proposes a methodology dedicated to the setting of a framework and a modeling of the aging for prognostics. This methodology is based on a deep literature review and degradation analyses of PEMFC stacks. This analysis allows defining a proper vocabulary dedicated to PEMFC׳s prognostics and health management and a clear limited framework to perform prognostics. Then the degradations review is used to select critical components within the stack, and to define their critical failure mechanisms thanks the proposal of new fault trees. The impact of these critical components and mechanisms on the power loss during aging is included to the model for prognostics. This model is finally validated on four datasets with different mission profiles both for health assessment and prognostics.
•A proper framework to perform PHM, particularly prognostics, of PEMFC is proposed.•A degradation analysis is performed.•A completely new model of PEMFC degradation is proposed.•SOH estimation is performed with very high coefficients of determination.
Building an accurate mathematical model is vital for the simulation, control, evaluation, management, and optimization of proton exchange membrane fuel cells (PEMFCs). Usually this work is processed ...through building a mathematical model based on empirical or semi-empirical equations firstly and then estimating the unknown model parameters using optimization technologies. In this study, a simple two stage eagle strategy based on JAYA algorithm and Nelder-Mead simplex algorithm is proposed for effectively estimating the unknown model parameters of PEMFCs. In the proposed strategy, JAYA algorithm is employed for the coarse global exploration, and Nelder–Mead simplex search algorithm is employed for the intensive local search. The effectiveness of the proposed strategy is verified through estimation experiments with 7 and 9 unknown parameters. Compared with the basic JAYA algorithm and four other newly reported excellent meta-heuristic algorithms including Grey Wolf Optimizer, Grasshopper Optimization Algorithm, Salp Swarm Optimizer, and Multi-Verse Optimizer, the proposed strategy possesses better performance in terms of accuracy, convergence speed, and stability, thus it is a promising approach for parameter estimation of PEMFC.
•A two stage eagle strategy is proposed for estimating the optimal parameters of PEMFC.•This strategy is based on JAYA algorithm and Nelder–Mead simplex search algorithm.•This strategy is examined using estimation experiments with 7 and 9 unknown parameters.•This strategy is compared with JAYA algorithm and four other recently-reported algorithms.•The obtained results indicate that this strategy is superior to the others.
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