Performance Of Proton Exchange Membrane Fuel Cell Research Articles

Impact of fuel starvation–induced anode carbon corrosion in proton exchange membrane fuel cells on the structure of the membrane electrode assembly and exhaust gas emissions: A quantitative case study

Although the durability of proton exchange membrane fuel cells (PEMFCs) is crucial for their broad commercial applications, current durability assessments do not encompass all operational scenarios. Startup/shut-down (SUSD) are among the most significant degradation factors in the city. To bridge this gap, we examine the phenomenon of fuel starvation, which leads to the rapid and irreversible degradation of PEMFC performance, particularly during SUSD, but has not been independently examined in the context of PEMFC durability. A quantitative methodology is used to analyze anode carbon corrosion and establish correlations with critical parameters under fuel starvation conditions. In particular, we quantify carbon loss based on (i) the composition or amount of the anode outlet gas emitted under such conditions and (ii) changes in the anode thickness at three distinct locations. The corresponding carbon losses due to 10 min of fuel starvation ((i): 212.0 μg cm−2, (ii): 189.6 ± 12.9 μg cm−2) agree well with each other. The largest decrease in the anode thickness (81.3 %) is observed near the outlet. The obtained insights provide guidance for the design of high-performance PEMFCs and the development of protective measures against the detrimental effects of fuel starvation.

Innovative air supply management in fuel cells: An economic predictive control approach without pre-measured OER

Existing fuel cell air supply control methods improve the economic performance of Proton Exchange Membrane Fuel Cells (PEMFC) under steady-state conditions through oxygen excess ratio curve, while ignoring the transient process of the air supply system under varying operating conditions. Furthermore, the oxygen excess ratio curve may exhibit deviations due to fuel cell aging and measurement inaccuracies, which would further diminish the economic performance derived from the control process. Not relying on pre-measuring the oxygen excess ratio curve, an EMPC (Economic Model Predictive Control) method is proposed for fuel cell air supply systems. It incorporates an economic cost function reflecting the economic objectives of the air supply system. By dynamically optimizing the parasitic power of the air compressor, this method enhances the overall economic performance by achieving performance optimization for both transient and steady-state processes of the fuel cell system. The asymptotic stability of PEMFC is achieved through the utilization of terminal penalty functions and terminal domain constraints. Stability and convergence analysis is carried out by employing auxiliary optimization problems and the Lyapunov method. In transient processes, EMPC method can achieve a maximum 4.97 % improvement in the economic performance of PEMFC. A hardware in loop (HIL) experiment was finally conducted to show the real-time capacity of the proposed EMPC method.

Unraveling the Influence of Nafion Content on the Performance of Proton-Exchange Membrane Fuel Cells from the Perspective of Triple-Phase Boundary.

By combining molecular simulations and experimental measurements, the effect of the Nafion content on the performance of proton-exchange membrane fuel cells (PEMFCs) is explained from the perspective of the triple-phase boundary (TPB). The evaporation process of Nafion solvent is simulated on a triple-phase model to mimic the formation of the TPB, and the influence of the Nafion content on the TPB structure is investigated. When the Nafion content is 1.415 mg/m2, the coverages of Nafion on both Pt particles and the carbon carrier are saturated at 42.1% and 32.7%, respectively. With the increase of Nafion content, the amount of water molecules around Pt particles is increased, and the surrounding O2 content is decreased. The experimental PEMFC performance has confirmed such simulation results, which demonstrates a trend of enhancing first and then weakening with the increase of Nafion content and reaches a maximum with the Nafion content of 2.96 mg/m2. Therefore, the correlation between the structure of the TPB and the cell's efficiency has been established at a molecular level, enabling enhancements in the design of the TPB morphology and an increase in PEMFC efficiency.

ZIF-8-derived nanocarbon composite-based highly active platinum group metal-free bimetallic electrocatalysts for oxygen reduction reaction in proton exchange membrane fuel cells

Non-precious metal catalysts are ideal low-cost substitutes of Pt/C for the sluggish oxygen reduction reaction (ORR), despite the serious stability challenges in proton exchange membrane fuel cells (PEMFC) to alleviate the energy crisis and environmental problems. Platinum group metal (PGM)-free bimetallic composite electrocatalysts are assumed to be an interesting route to be investigated to address the stability and ORR selectivity related issues in PEMFC conditions. In this regard, we propose a simple and facile synthesis route by a composite of multi-walled carbon nanotubes and zeolitic imidazolate framework (ZIF)-8 followed by impregnating dual transition metals (FeMn, FeCo, and CoMn) and evaluate their ORR activity in acid media and PEMFC performance. Various catalyst materials are prepared and optimized to achieve the highest electrocatalytic performance. The prepared catalysts are characterized by various physico-chemical methods to elucidate their textural, structural, and morphological properties. The high ORR electrocatalytic activity and selectivity of the catalyst are reported in terms of half-wave potential and low H2O2 yield as determined by the rotating ring-disk electrode method. The significant electrochemical stability under accelerated durability test and high peak power density (787 mW cm−2) in H2-O2 PEMFC made these catalysts as potential candidates for efficient alternatives to PGMs in the fuel cell cathodes.

Study on the Performance Degradation of Membrane Electrode Assembly in Proton Exchange Membrane Fuel Cell Caused by Freeze–Thaw Cycles

ABSTRACTDurability of membrane electrode assembly (MEA) is a serious problem to be overcome in the commercial development of proton exchange membrane fuel cell (PEMFC). The change in volume due to water–ice conversion has an irreversible effect on the MEA, which affects the performance of PEMFC. For investigating the optimal initial water content of MEA that minimizes the impact on PEMFC performance after freeze–thaw (F/T) cycles, this study first measured the high‐frequency resistance to determine the water content of MEA, and then subjected five MEAs with different water contents to 60 F/T cycles at −20°C to 30°C. The fuel cell output performance of five MEAs was found to be inconsistently degraded by polarization curve tests, with the cells of the two MEAs with the lowest and highest water contents exhibiting the worst output performance. Electrochemical impedance spectroscopy curves proved that the difference in resistance change after F/T cycles is one reason why the cell output performance is degraded differently. Finally, the degradation of cell performance was further explained by cyclic voltammetry. These results indicate that MEA has the best output performance for F/T cycles at an initial water content of 3.0.

Performance evaluation and economic analysis of integrated solid oxide electrolyzer cell and proton exchange membrane fuel cell for power generation

In order to generate clean electricity from thermal energy, a hybrid electrochemical system is conceptually developed by coupling the proton exchange membrane fuel cell (PEMFC) and solid oxide electrolyzer cell (SOEC). For evaluating the proposed hybrid system, firstly, the two subsystems are modeled numerically and then they are merged into an integrated SOEC-PEMFC system. Moreover, the SOEC-PEMFC is analytically modeled for further evaluation. The effects of important operational parameters are examined. The outcomes show that when the SOEC operating temperature increases from 823 to 1273 K, the efficiency increases from 18.7 % to 38 % and the net output power improves about 36 % while cost per unit of power of hybrid system decreases about 80 %. Furthermore, by increasing the PEMFC operating temperature from 323 to 348 K, the system net output power and efficiency increase about 16.7 % and 10 %, respectively, whilst the cost per unit of electricity decreases about 19 %. In addition by increasing operating pressure of system, the net output power and efficiency are also improved. The proposed system has maximum output power density of 3.9 kW.m−2 and maximum efficiency of 38 %. In addition, the SOEC-PEMFC system is compared with the previously studied proton exchange membrane electrolyzer cell-proton exchange membrane fuel cell (PEMEC-PEMFC) system. In comparison with the previous PEMEC-PEMFC system, the present system's cost per unit of power and efficiency are about 16 % and 17 % higher, respectively; while the output power density is about double that of the PEMEC-PEMFC system. Generally, because hydrogen-powered systems offer reliable operation from an economic and energetic perspective, the SOEC-PEMFC system represents a promising technological solution to the clean energy demands.

Deciphering nanostructural evolution of PtCu/C–N electrocatalyst via identical location transmission electron microscopy imaging: Gram-scale synthesis and superior activity in oxygen reduction reaction

Electrocatalysts play a pivotal role in advancing proton-exchange membrane fuel cell (PEMFC) for hydrogen energy applications. In this study, we investigate a novel PtCu/CN electrocatalyst synthesized via a gram-scale synthesis approach, which demonstrates remarkable activity and stability in the oxygen reduction reaction (ORR). The catalyst's effectiveness stems from its unique structure, combining bimetallic nanoparticles (NPs) and an N-doped carbon support. Employing identical location transmission electron microscopy (IL-TEM) imaging, we observe significant NP structure reorganization upon activation influenced by the upper limiting potential. Notably, the PtCu/CN catalyst activated to 1.0 V surpasses the United States Department of Energy (DOE) target for ORR activity by 3.3-fold. These findings underscore the potential of this catalyst in enhancing the performance of PEMFCs, marking a significant advancement in hydrogen energy technology.

Oxygen excess ratio feedforward control based on ESO for PEMFC in DC off-grid hydrogen production systems

Oxygen excess ratio (OER), which is influenced by the air flow input to the cathode, is one of the important factors affecting the performance of fuel cell system. Insufficient oxygen supply will result in a sharp drop in output voltage, while an excessive supply will bring about a large parasitic power load on the air compressor, reducing the net output power of the system and operating efficiency. Both insufficient and excess oxygen supply can adversely affect the operating life of the proton exchange membrane fuel cell (PEMFC). Due to the serious nonlinear, hysteresis, uncertainty and interference in the process of OER control, this paper proposes an OER feedforward control based on extended state observer (ESO) for a PEMFC auxiliary system with the ESO to predict the total disturbance to improve the dynamic response of the system with large time delay utilizing terminal sliding mode control (TSMC). The control strategy is divided into two stages. The first stage constructs an ESO to realize real-time observation of the state variables required for the internal operation of the auxiliary machine system and the PEMFC, and yields the air compressor voltage control signal through terminal sliding mode control. In the second stage, combined with V/f control for the compressor, the transmitted air flow is adjusted, ultimately achieving the goal of changing the OER of the PEMFC and improving operating efficiency. The simulation results show that the proposed control strategy has good anti-interference capabilities, a faster response, and less overshoot. The gas flow transmission in the gas supply system is more robust, the PEMFC operation is safer, and its lifespan is extended.

Magnetic Array-Aided Visualizing PEMFC Degradation Heterogeneity.

Analyzing degradation heterogeneity of proton exchange membrane fuel cell (PEMFC) while maintaining high practicality is consistently challenging, primarily due to the destructive and costly nature of existing techniques relying on material characterization. In this work, a designed magnetic array integrating 16 sensors within 25cm2 space is used for direct scanning and imaging of PEMFC performance heterogeneity during its degradation. Results are validated through degradation mechanism analysis and material characterization, confirming its potential in guiding the development of durable materials.

Machine learning and Bayesian optimization for performance prediction of proton-exchange membrane fuel cells

Proton-exchange membrane fuel cells (PEMFCs) are critical components of zero-emission electro-hydrogen generators. Accurate performance prediction is vital to the optimal operation management and preventive maintenance of these generators. Polarization curve remains one of the most important features representing the performance of PEMFCs in terms of efficiency and durability. However, predicting the polarization curve is not trivial as PEMFCs involve complex electrochemical reactions that feature multiple nonlinear relationships between the operating variables as inputs and the voltage as outputs. Herein, we present an artificial-intelligence-based approach for predicting the PEMFCs’ performance. In that way, we propose first an explainable solution for selecting the relevant features based on kernel principal component analysis and mutual information. Then, we develop a machine learning approach based on XGBRegressor and Bayesian optimization to explore the complex features and predict the PEMFCs’ performance. The performance and the robustness of the proposed machine learning based prediction approach is tested and validated through a real industrial dataset including 10 PEMFCs. Furthermore, several comparison studies with XGBRegressor and the two popular machine learning-based methods in predicting PEMFC performance, such as artificial neural network (ANN) and support vector machine regressor (SVR) are also conducted. The obtained results show that the proposed approach is more robust and outperforms the two conventional methods and the XGBRegressor for all the considered PEMFCs. Indeed, according to the coefficient of determination criterion, the proposed model gains an improvement of 6.35%, 6.8%, and 4.8% compared with ANN, SVR, and XGBRegressor respectively.

Advanced Nafion/nanofiller composite proton exchange membranes for fuel cell applications

Proton exchange membrane fuel cells (PEMFCs) exhibit increasing potential in a variety of applications, from automotive to stationary power generation, due to their superior advantages such as high efficiency, quick start-up and low emissions. The cell performance and operation life of PEMFCs are directly affected by the proton exchange membranes (PEMs). Nafion, a well-known perfluorosulfonic acid polymer, represents the state of the art of PEMs. To further improve the performance of Nafion, various nanofillers are incorporated into Nafion matrices, leading to the formation of composite PEMs with enhanced proton conductivity, mechanical strength and chemical stability. This review summarizes the recent advancements in Nafion composite PEMs based on four typical kinds of nanofillers: framework nanomaterials, carbon nanomaterials, polyoxometalate nanoclusters, and inorganic oxide nanoparticles. The preparation strategy, structure-property relationship and fuel cell applications of these membranes are discussed comprehensively, particularly focusing on the synergistic effect between Nafion and nanofillers. This review can provide an instructive insight for designing high-performance PEMs towards emerging energy technologies.

Sensitivities of critical operating conditions on proton exchange membrane fuel cell performance: an experimental study

Abstract The performance of the Proton Exchange Membrane Fuel Cell (PEMFC) is subject to substantial influence from operating conditions. In this paper, the impact of various operating conditions on the polarization curves is examined through single-variable polarization curve tests. Notably, it is observed that the polarization curves intersected within the range of 1.0 A/cm2 to 1.5 A/cm2 under varying cathode inlet humidity and working pressure conditions. Expanding upon this observation, an orthogonal experiment is designed and executed to evaluate the sensitivity of PEMFC performance to diverse operating conditions under two distinct current densities of 1.0 A/cm2 and 2.0 A/cm2. Consequently, it is revealed that the output voltage, charge transfer impedance, and mass transfer impedance are most significantly influenced by three specific operating conditions: temperature, cathode inlet humidity, and stoichiometric ratio. Furthermore, as the current density increases, the dominant factors governing PEMFC performance have evolved from temperature-dominated charge transfer impedance to cathode stoichiometric ratio-dominated mass transfer impedance.

Numerical investigation on dynamic characteristics of the droplet impacting on a random rough surface

Water management is a significant problem affecting the reliability and stability of proton exchange membrane fuel cells (PEMFC), in which droplet wall collision is the critical factor affecting the liquid water transmission in the gas channel. The surface roughness directly affects the spreading deformation of the droplet after impacting. This study's influence of surface roughness on the dynamic process of a single droplet of micrometer level impacting random rough surfaces was numerically investigated. Based on the Weierstrass–Manderlbrot (W-M) fractal theory, three-dimensional random rough surfaces with five roughness levels were established, and the dynamic process of droplet impact on the random rough surface was captured. The contour features of the droplet were analyzed, and the results showed that rough peaks hinder the spreading and retracted process of droplets, resulting in a thicker liquid film deposited on the rough surface, which is not conducive to liquid water discharge. The higher roughness level makes it difficult for droplets to gather into liquid film after hitting the wall and further hinders the discharge of liquid water from the flow channel. Therefore, when micrometer-sized droplets collide with a wall velocity of about 10 m/s, the roughness Ra should be controlled below 0.4 μm, which is conducive to the formation of thin liquid film after droplet impact and the effective discharge of water, which is crucial to maintaining the performance and life of PEMFC.

Proton exchange membrane fuel cells: processes–materials–design in current trends

Over the last decade, the potential of proton exchange membrane fuel cells (PEMFCs) for use in a range of applications, including automotive transport, has attracted the attention of scientific groups and industry representatives worldwide. The active development of PEMFCs is already enabling them to compete with internal combustion engines and lithium-ion batteries in a number of applications. However, significant improvements in a number of PEMFCs characteristics are required to expand the scope of their applications. This review is intended to bridge the gap between existing reviews, which are either overly general or overly specific, and provide a comprehensive overview of the current state of the art and potential future applications of PEMFCs. It will focus on the main components of PEMFCs, including proton exchange membranes, catalytic and gas diffusion layers, bipolar plates, and cooling systems, and the factors affecting the PEMFC performance.<br> The bibliography includes 428 references.

A predictive framework for PEMFC dynamic load performance degradation based on feature parameter analysis

Accurate and swift estimation of the future performance degradation of Proton Exchange Membrane Fuel Cells (PEMFCs) is crucial for the health management of PEMFC. However, most existing studies primarily concentrate on uncovering the inherent patterns of performance degradation parameters, neglecting the fundamental relationships and pattern variations between performance degradation and other characteristic parameters (such as flow rate, temperature, and pressure). This paper seeks to address this research gap. To that end, we delve into feature parameters, extracting underlying patterns of feature evolution to construct a feature exploration-based framework for predicting PEMFC performance degradation. Initially, Time-Varying Filtered Empirical Mode Decomposition (TVF-EMD) is employed to decompose each feature variable, isolating the core information of the features. Furthermore, to reduce the computational burden caused by redundant features, Uniform Manifold Approximation and Projection (UMAP) is used to perform dimensionality reduction on the decomposed feature subsequences, ensuring the efficiency and representativeness of the extracted features. Finally, to overcome the shortcomings of long short-term memory networks (LSTM) in terms of convergence and the effective use of time series information, we introduce an innovative Mogrifier LSTM (M-LSTM) model to enhance the accuracy of PEMFC performance degradation predictions. The experimental and validation results demonstrate that the extraction of feature parameters significantly enhances the predictive precision of the baseline model. Relative to the compared models, there was an improvement of at least 16.859% in Root Mean Square Error (RMSE), a minimum increase of 23.333% in Mean Absolute Error (MAE), and a boost of no less than 0.913% in the coefficient of determination (R2). Simultaneously, the proposed predictive framework demonstrates good stability and accuracy in predicting PEMFC performance degradation.

Tailoring Zirconia Supported Intermetallic Platinum Alloy via Reactive Metal‐Support Interactions for High‐Performing Fuel Cells

AbstractDeveloping efficient and anti‐corrosive oxygen reduction reaction (ORR) catalysts is of great importance for the applications of proton exchange membrane fuel cells (PEMFCs). Herein, we report a novel approach to prepare metal oxides supported intermetallic Pt alloy nanoparticles (NPs) via the reactive metal‐support interaction (RMSI) as ORR catalysts, using Ni‐doped cubic ZrO2 (Ni/ZrO2) supported L10−PtNi NPs as a proof of concept. Benefiting from the Ni migration during RMSI, the oxygen vacancy concentrations in the support are increased, leading to an electron enrichment of Pt. The optimal L10−PtNi−Ni/ZrO2−RMSI catalyst achieves remarkably low mass activity (MA) loss (17.8 %) after 400,000 accelerated durability test cycles in a half‐cell and exceptional PEMFC performance (MA=0.76 A mgPt−1 at 0.9 V, peak power density=1.52/0.92 W cm−2 in H2−O2/−air, and 18.4 % MA decay after 30,000 cycles), representing the best reported Pt‐based ORR catalysts without carbon supports. Density functional theory (DFT) calculations reveal that L10−PtNi−Ni/ZrO2−RMSI requires a lower energetic barrier for ORR than L10−PtNi−Ni/ZrO2 (direct loading), which is ascribed to a decreased Bader charge transfer between Pt and *OH, and the improved stability of L10−PtNi−Ni/ZrO2−RMSI compared to L10−PtNi−C can be contributed to the increased adhesion energy and Ni vacancy formation energy within the PtNi alloy.

Tailoring Zirconia Supported Intermetallic Platinum Alloy via Reactive Metal-Support Interactions for High-Performing Fuel Cells.

Developing efficient and anti-corrosive oxygen reduction reaction (ORR) catalysts is of great importance for the applications of proton exchange membrane fuel cells (PEMFCs). Herein, we report a novel approach to prepare metal oxides supported intermetallic Pt alloy nanoparticles (NPs) via the reactive metal-support interaction (RMSI) as ORR catalysts, using Ni-doped cubic ZrO2 (Ni/ZrO2) supported L10-PtNi NPs as a proof of concept. Benefiting from the Ni migration during RMSI, the oxygen vacancy concentrations in the support are increased, leading to an electron enrichment of Pt. The optimal L10-PtNi-Ni/ZrO2-RMSI catalyst achieves remarkably low mass activity (MA) loss (17.8 %) after 400,000 accelerated durability test cycles in a half-cell and exceptional PEMFC performance (MA=0.76 A mgPt -1 at 0.9 V, peak power density=1.52/0.92 W cm-2 in H2-O2/-air, and 18.4 % MA decay after 30,000 cycles), representing the best reported Pt-based ORR catalysts without carbon supports. Density functional theory (DFT) calculations reveal that L10-PtNi-Ni/ZrO2-RMSI requires a lower energetic barrier for ORR than L10-PtNi-Ni/ZrO2 (direct loading), which is ascribed to a decreased Bader charge transfer between Pt and *OH, and the improved stability of L10-PtNi-Ni/ZrO2-RMSI compared to L10-PtNi-C can be contributed to the increased adhesion energy and Ni vacancy formation energy within the PtNi alloy.

Microscale structure optimization of catalyst layer for comprehensive performance enhancement in proton exchange membrane fuel cell

The catalyst layer plays a significant role in promoting the redox reaction of proton exchange membrane fuel cells (PEMFC). Especially at high current densities, as the oxygen reduction rate increases and more water is produced, the pores of the catalyst layer are easily clogged, thus preventing the oxygen from reaching the reactive sites. In this work, a cathode catalyst layer with micro-grooved structure is proposed to optimize the water-gas transport and output performance of PEMFC. Three-dimensional two-phase numerical simulation results show that the catalyst layer with grooves significantly improves the water-gas transport performance of PEMFC, with a maximum increase of 4.76 % in output performance. Combining the response surface methodology and non-dominated sorting genetic algorithm-II for multi-objective optimization (MOO), the optimal solution corresponding to anode/cathode relative humidity and ionomer volume fraction is confirmed to be 86.73 %, 80.10 %, and 0.2592, respectively. The optimization objectives (oxygen concentration, liquid saturation, and net power density) are improved by 3.88 %, 1.95 %, and 1.79 %, respectively. The differences between the three optimization objectives obtained by numerical simulation verification are only 0.61 %, 0.32 %, and 0.55 %, indicating that the MOO results are reliable and accurate.

Experimental Investigation for Proton Exchange Membrane Fuel Cells in Marine Salt Spray Environment.

In the maritime setting, Proton Exchange Membrane Fuel Cells (PEMFCs) are subjected to salt spray, posing a risk of contaminating internal components and leading to irreversible degradation in the performance of the PEMFCs. Thus, it is crucial to assess the impact of sodium chloride contamination on PEMFC operation. To address challenges related to prolonged cycle times, high costs, and intricate sample preparation in sodium chloride contamination experiments for PEMFCs, this Article replicates the marine atmospheric conditions using a standard salt spray experimental chamber. The liquid nitrogen fracture method is employed for cost-effective and efficient preparation of experimental samples. The meteorological environment with varying salt content in the salt spray is achieved through precise control of sodium chloride concentration. The Article systematically presents the salt spray experimental method for the membrane electrode assembly (MEA) of PEMFCs. A dedicated salt spray experimental rig was constructed to validate this method for the MEA of PEMFCs. The results indicate that the salt spray experimental method for the MEA of PEMFCs can effectively explore internal component contamination and is well-suited for analyzing the physicochemical effects of NaCl on MEA components, along with their microscopic characterization under salt spray conditions.

Coupled optimization of auxiliary channels and porosity gradient of GDL for PEMFC

In this study, we proposed a novel under-rib auxiliary channel and developed a systematic methodology combining computational fluid dynamics (CFD), an artificial neural network (ANN), and a particle swarm optimization (PSO) algorithm for the coupled optimization of the auxiliary-channel structure and gas diffusion layer (GDL) porosity gradient in a proton exchange membrane fuel cell (PEMFC). First, we developed a three-dimensional multiphase numerical model of a non-isothermal parallel flow-field PEMFC. ANN was then applied to obtain a mapping relationship between auxiliary channels structure, GDL porosity gradient and output performance of PEMFC with finite CFD data. Finally, PSO was employed to perform an optimization search to determine the optimal parameter pairing, resulting in a 16.7 % increase in maximum power density and a 20.6 % increase in the current operating range. In addition, the optimized PEMFC exhibited superior mass transfer and water removal capabilities, where the average oxygen concentration in the intermediate section of cathode GDL was increased by 33.3 % and the maximum liquid water saturation was reduced by 23.5 %. Moreover, the coupled optimization of the auxiliary channels and the GDL porosity gradient can increase power density by at least 8.7 % and current density by 9.1 % compared to single component optimization.