Cathode Humidification Research Articles

Operation parameters study on the performance of PEMFC based orthogonal test method

By selecting five key operational parameters—inlet temperature, operating temperature, anode humidity, cathode humidity, and operating pressure—and using PEMFC power density, membrane temperature difference, and membrane water content as performance indicators, simulations were conducted using 3D CFD modeling and orthogonal experiments to identify the most significant factors influencing PEMFC performance and determine the optimal operational parameter combination. The results show that working pressure has the most significant impact on PEMFC performance. Pressure variations cause significant changes in diffusion and heat conduction within the PEMFC. When the working pressure increases from 1.0 MPa to 3.0 MPa, the power density increases by approximately 11.2 %, but the temperature difference within the membrane increases by about 30.5 %. The difference between operating temperature and inlet temperature directly leads to changes in the temperature difference within the membrane. Moreover, changes in operating temperature greatly affect the water content within the proton exchange membrane, which in turn impacts the PEMFC's power density. When the operating temperature increases from 60 °C to 100 °C, the water content within the membrane decreases by approximately 50.5 %, and the power density decreases by 60.4 %. By optimizing the combination of operating parameters using a comprehensive scoring method, the temperature difference within the membrane can be controlled at 27.78 °C while ensuring the power density is increased to 0.92 W/cm2.

Cathode fine-scale flow channel optimization enhancing the performance of proton exchange membrane fuel cells

High performance and long durability have been the continuous pursuit of proton exchange membrane fuel cells (PEMFCs). Performance and durability are related to the PEMFC distributional uniformity of internal state, which are deeply influenced by the flow channel structures and operating conditions. Therefore, this study proposes a fine-scale flow channel (FSFC) with gradually decreasing flow channel widths (wch) based on parallel flow field. Following, fixing wch at 0.3 mm, the effects of different rib width (wrib), cathode humidity (RHc), stoichiometric ratio (ξc) and coolant mass flow rate (mcool) are studied. Simulation results indicate that FSFC can significantly enhance the various properties of fuel cells, especially the performance and uniformity. Reducing the wrib can enhance the performance and reduce the pressure drop. The appropriate RH and ξc can improve the performance and uniformity while avoiding flooding and purging effects. Similarly, mcool should be kept in the appropriate range to avoid unnecessary pump power loss. This study aims to develop the flow fields in a more fined direction, offering solutions that strike a balance between durability and power density for PEMFC optimization.

Heteroatom-Doped Defects Anchoring Nano-Pt for High-Stability and Low-Humidity Proton Exchange Membrane Fuel Cell.

To meet the ever-increasing demand of proton exchange membrane fuel cell (PEMFC), it is necessary to carry out structure optimization for low-cost and high-stability oxygen reduction reaction (ORR) catalysts. Herein, a zeolitic imidazolate framework (ZIF)-derived carbon material with a mass of heteroatoms and defects is developed and serves as advanced support for nano-Pt-based ORR catalysts. This unique structure enhances the interaction between nano-Pt and support, leading to higher ORR intrinsic activity. During fuel cell applications, it demonstrates impressive water-retaining capacity and electrochemical stability. Under H2-O2 supply without cathode humidification, this catalyst achieves high mass activity of 0.475 A mgPt -1, with only 7.4% attenuation in maximum power density after 20 000 cycles of accelerated durability test, highlighting its remarkable potential for fuel cell applications. Physicochemical characterization and theoretical simulation reveal the crucial anchoring effect of heteroatom-doped defects to nano-Pt, providing valuable insights for further ORR catalyst design and PEMFC applications.

Experimental study on voltage instability of proton exchange membrane fuel cell: Types and boundaries

ABSTRACT This paper presents an experimental study on the voltage instability in proton exchange membrane fuel cells operating at high current densities, which is important for improving their reliability and durability. Based on experimental findings regarding transparent fuel cells, a method is proposed to identify different types of voltage instability via statistical results of linear changing rate and oscillation amplitude. The types and boundaries of voltage instability are elucidated while evaluating the impact of cathode relative humidity and flow rate on voltage instability. The findings reveal that (1) the voltage instability is greatly influenced by the cathode-side relative humidity and flow rate, (2) there are three typical types of voltage instability: voltage decline, voltage oscillation, and both, and (3) voltage decline occurs at low cathode humidity, while voltage oscillation becomes more severe at large cathode humidity and low flow rate; (4) Reduction of water content in the membrane leads to voltage decline, while an increase in water content in the catalyst layer, gas diffusion layer, and channels leads to voltage oscillation. A full-condition map diagram demonstrating voltage instability during high current density conditions is presented. The method for creating this map for voltage instability will be employed to enhance fuel cell performance.

Dynamics Management of Intermediate Water Storage in an Air-Breathing Single-Cell Membrane Electrode Assembly.

In air-breathing proton exchange membrane fuel cells (Air PEM FCs), a high rate of water evaporation from the cathode might influence the resistance of the membrane electrode assembly (MEA), which is highly dependent on the water content of the Nafion membrane. We propose a dead-end hydrogen anode as a means of intermediate storage of water/humidity for self-humidification of the membrane. Such an inflatable bag integrated with a single lightweight MEA FC has the potential in blimp applications for anode self-humidification. A dynamic numerical water balance model, validated by experimental measurements, is derived to predict the effect of MEA configuration, and the membrane's hydration state and water transfer rate at the anode on MEA resistance and performance. The experimental setup included humidity measurements, and polarization and electrochemical impedance spectroscopy tests to quantify the effect of membrane hydration on its resistance in a lightweight MEA (12 g) integrated with an inflatable dead-end hydrogen storage bag. Varying current densities (5, 10, and 15 mA/cm2) and cathode humidity levels (20, 50, and 80%) were examined and compared with the numerical results. The validated model predicts that the hydration state of the membrane and water transfer rate at the anode can be increased by using a thin membrane and thicker gas diffusion layer.

Experimental evaluation of proton exchange membrane fuel cell performance with sinusoidal flow channel designs

Proton Exchange Membrane Fuel Cells (PEMFCs) with three distinct flow field designs were investigated: sinusoidal with a diffuser at the intake, sinusoidal serpentine, and serpentine flow fields. The sinusoidal flow field with a diffuser at the intake has been found to be the best flow field design. Following that, parametric experiments were performed on PEMFCs equipped with a sinusoidal flow field with a diffuser at the intake. Operating pressures (1–3 bar), back pressures (0–3 bar), anode humidification temperatures (40 °C–80 °C), cathode humidification temperatures (40 °C–70 °C), anode flow rates (250 sccm to 350 sccm) and cathode flow rates (250 sccm to 400 sccm) and cell operating temperatures (COT) ranging from 40 °C to 70 °C were all adjusted. The experimental findings showed that a COT of 60 °C, a 3-bar back pressure, a 3-bar working pressure, cathode humidification at 70 °C, anode humidification at 60 °C, and flow rates of 300 sccm for the anode and 350 sccm for the cathode resulted in the best PEMFC performance.

Effects of temperature and cathode humidity on performance of PEM full cell

The performance of proton exchange membrane fuel cells (PEMFCs) is significantly influenced by their temperature and cathode humidity, as they affect power density and internal water distribution. The interdependent nature of these two parameters necessitates their simultaneous consideration in practical engineering to achieve high efficiency and reliable PEMFC operation. Therefore, this study proposes a synergistic analysis of the dual-parameter effect of working temperature and cathode humidity on PEMFC performance, using a three-dimensional steady-state model for counter-flow single-channel PEMFCs. The model's correctness is verified through comparison with experimental results, and the resulting power density and internal water distribution characteristics of PEMFCs are studied based on voltage changes. The findings indicate that the sensitivity of the proton exchange membrane (PEM) to temperature and cathode humidity varies at different voltage stages. Coupling analysis of these two factors enhances proton exchange membrane conductivity and expands the range of power density adjustment. Consequently, this study provides crucial insights into the interplay between temperature and cathode humidity in PEMFCs, facilitating the design and optimization of PEMFC systems for practical engineering applications.

Voltage distribution analysis and non-uniformity assessment in a 100 cm2 PEM fuel cell stack

In this study, a comprehensive set of experimental tests were carried out to investigate individual cell voltage and temperature deviation under different operating conditions in a fuel cell stack. Five key operating conditions were considered: temperature, pressure, anode and cathode relative humidity, and cathode stoichiometry. Different configurations of reactant flow within the stack were also investigated. A 100 cm2 7-cell stack was used for the experiments, and voltage and temperature measurements were taken for each individual cell. Both ANOVA and range analysis method were used to evaluate the results. The findings showed that the performance of the external cells was consistently lower than that of the central ones since its temperature, the parameter that most affected performance, was also lower due to heat losses. Additionally, voltage deviation increased with temperature deviation. The study also revealed that stack performance was improved by an increase in temperature, pressure and cathode stoichiometry, whereas the effect of anode and cathode humidity was not so significant in the studied range. Furthermore, gravity played a clear role in water management, hindering the removal of condensed water for flow configurations where reactant gases were fed from the bottom interfaces of the stack.

Model-based observer for vehicle proton exchange membrane fuel cell humidity based on adaptive sliding mode estimation technique

Real-time humidity acquisition for vehicle proton exchange membrane fuel cell (PEMFC) facilitates humidity control to avoid membrane flooding or drying, improving its efficiency and stability. However, due to the frequent changes of actual vehicle conditions and expensive as well as unreliable humidity sensors, it is difficult to obtain real-time water content in PEMFC, which brings obstacles to closed-loop control of humidity. To this end, a model-based observer is proposed to obtain real-time humidity. Specifically, a dimensionless third-order model of relative humidity for PEMFC was established, which includes the dynamic of membrane water content. Based on the proposed model, an adaptive sliding mode convergence algorithm was designed to approach real-time humidity using measurable signals (voltage, current, pressure, flow rate, and temperature). The exploration of proposed adaptive sliding mode observer (ASMO) performance was compared with non-adaptive sliding mode observer (SMO) and classical ASMO by using a real 80 kW commercial fuel system experimental data. The experimental results show that compared with second-order humidity model, proposed third-order humidity model reduced recovery time under small step condition, where 250 s for cathode humidity estimation and 200 s for anode humidity estimation. In addition, under the small step condition, the average error of the three observers was less than 3%, which is accurate for engineering application. Moreover, proposed ASMO had the minimum static error, with 4% for cathode humidity estimation and 9% for anode humidity estimation under large step conditions as well as MAE, MSE, RMSE with 4%, 1.90%, 4.39% for cathode relative humidity estimation, 8.19%, 0.89%, 9.44% for anode relative humidity estimation respectively. The comprehensive results indicate that the proposed ASMO with adaptive parameters tuning has better dynamic performance than non-adaptive SMO as well as classical ASMO in terms of robustness and estimated accuracy.

Hydrophobicity enhancement of gas diffusion layer induced by hydrothermal deposition process and the electrochemical performance of proton exchange membrane fuel cell

Gas diffusion layer (GDL) with balanced water management capacity facilitates the power density enhancement of proton exchange membrane fuel cells (PEMFCs). In this paper, hydrothermal deposition (HD) method was utilized to enhance the hydrophobicity of GDL, which results in enhanced water retention capacity at both the ambient and cell operation temperatures (25 and 80 ℃). The competitive working mechanism of hydrophobicity and temperature on the water transport behavior inside GDL was implied in terms of the surface hydrophobicity of carbon fiber using molecular simulations. And the surface hydrophobicity of carbon fiber in GDL was dominant by the surface roughness at working temperature. The enhanced water retention capacity of GDL further improves the electrochemical performance of fuel cell at low humidity. Fuel cell assembled with cathode HD-GDL displays higher peak power density than that of the commercial reference Toray GDL (CR-GDL) at low applied cathode humidity ranges (RH 0-20%). The findings in this paper offers a facile and practical approach for tailoring the water management capacity of GDL and further the electrochemical performance of PEMFC under low humidity.

Enhancing the performance of proton exchange membrane fuel cell using nanostructure gas diffusion layers with gradient pore structures

The gas diffusion layer (GDL) plays a vital role in water management of proton exchange membrane fuel cells. In this study, GDLs with nanoscale gradient pore sizes (nano-GDLs) are fabricated using electrospinning to explore the influence of the gradient layer number and degree of the pore size gradient on the water transport performance. The breakthrough pressure and water saturation tests indicate that nano-GDLs with uniform and gradient structures have higher breakthrough pressures and lower water saturation compared with those of the commercial Toray GDL, which facilitates back diffusion of water through the membrane and water discharge in the GDL. Specifically, among the nano-GDLs with a gradient structure, the three-layer medium-gradient nano-GDL sample (3-MG) possesses the maximum breakthrough pressure and minimum water saturation ratio. The fuel cell test determined that the maximum power density of the 3-MG nano-GDL sample is 14% higher than that with commercial Toray GDL without cathode humidification.

Revealing the dynamic temperature of the cathode catalyst layer inside proton exchange membrane fuel cell by experimental measurements and numerical analysis

Temperature variation inside the cathode catalyst layer (CCL) is significant, which could greatly damage fuel cell performance and durability. However, limited by CCL microstructure and complex physicochemical processes, the knowledge regarding CCL dynamic temperature is indeed insufficient. Thus, this work integrates a pre-prepared thin-film microsensor into the fuel cell to measure CCL surface temperature under dynamic load. At the same time, an improved transient thermal model considering local mass transport and liquid effect on thermal contact resistance (TCR) is established for the first time to analyze the internal process. Results show that CCL temperature is greatly affected by local resistance and interface accumulated water. And, as confirmed by both experiment and simulation, the CCL surface exhibits 0–7 °C temperature variation, whose profile changes sharply at the beginning and then evolutes slowly, eventually taking tens or hundreds of seconds to reach a new steady state due to thermal inertia. Moreover, the temperature is further increased by ∼1 °C as cathode humidity increases or stoichiometric ratio decreases, but only slight changes with the anode condition. The significant role of cathode operation is attributed to the greater mass transfer resistance and more sensitive intrinsic oxygen reduction reaction to reactant change. This study is expected to provide a deeper understanding of CCL dynamic temperature, thus improving fuel cell thermal management.

Oxidant starvation under various operating conditions on local and transient performance of proton exchange membrane fuel cells

Oxidant starvation in proton exchange membrane fuel cells could cause severe fluctuation on dynamic performance and the significant reduction in durability. In this work, dynamic transfer and distribution characteristics of reactants and water under oxidant starvation are studied by measuring local current densities, temperatures, and the cell voltage in situ. Besides, high frequency resistance and pressure drop along the flow channel at the cathode are obtained to determine the membrane hydration state, and mass transfer and distribution. The effects of cathode humidity, cell temperature and operating modes on the local and overall transient behavior of the cell under oxidant starvation are analyzed. The experimental results show that with the air stoichiometry of 0.8, the current fluctuation distribution is much non-uniform and hydrogen pumping occurs in the downstream. When oxidant starvation occurs under potentiostatic mode, current densities in the upstream gradually increase to the steady-state; while under galvanostatic mode, local current densities in the upstream show overshoots and current variations coefficient along the flow channel are about two times of potentiostatic mode. As cell temperature increases, severe oxygen starvation occurs in the downstream and local temperature differences tend to be larger. When the unhumidified air is supplied into the cell, the combined effect of local membrane hydration state and local oxygen concentration plays a dominant role, leading to greater magnitudes of current fluctuation and higher change rate of current variation coefficient in the downstream.

Inconsistency evaluation of vehicle-oriented fuel cell stacks based on electrochemical impedance under dynamic operating conditions

The dynamic inconsistency performance of the proton exchange membrane fuel cell stack is a crucial indicator for vehicular applications. This paper comprehensively studies for the first time the local dynamic inconsistency of a high-power fuel cell stack with 30 kW rated power based on impedance. The stack is divided into ten groups equally. First, each polarization process and frequency impedance under different working conditions is quantitatively analyzed by the equivalent circuit model combined with the relaxation time distribution. It is determined that 1 Hz, 50 Hz, and 2500 Hz impedance can describe the oxygen transport, charge transfer, and ohmic variation trends, respectively. Then, the effects of loads, air stoichiometry, backpressure, operating temperature, and cathode humidity on in-stack dynamic inconsistency response are evaluated from an internal dynamics perspective. The results show that the local dynamic inconsistent responses in the fuel cell stack depend mainly on the oxygen transfer capacity. Oxygen transport affects the difference in local voltage transient drop after a current step and the inconsistency voltage recovery. These works provide an in-depth understanding of the differences in the dynamic response of high-power fuel cell stacks, which has an important implication for system control and structural design optimization.

Modeling analysis of polymer electrolyte membrane fuel cell with regard to oxygen and charge transport under operating conditions and hydrophobic porous electrode designs

Increasing the power density of polymer electrolyte membrane fuel cells (PEMFCs) is vital for their commercial application but requires detailed knowledge of the charge, oxygen, and water transport mechanisms. In this study, an improved multi-phase non-isothermal PEMFC model coupled with a detailed catalyst-layer (CL) agglomerate model is developed to investigate the performance characteristics under different operating conditions and hydrophobic porous electrode designs. During the parametric analysis, the oxygen and charge transport behaviors on cell performance are analyzed, the contributions of bulk and local oxygen transport to the entire oxygen transport process are revealed, and the corresponding water retention, drainage, and transport are evaluated to clarify the internal mechanisms of oxygen transport and membrane hydration. It is found that an increase in temperature can accelerate the membrane water back diffusion and hence improve the sluggish charge transport. Increasing the relative humidity (RH) enhances the cell performance. The local oxygen and charge transport resistances decrease with an increase in the RH owing to the higher membrane hydration. The presence of microporous layer (MPL) improves the liquid-water retention capacity, deteriorating the bulk oxygen transport due to liquid-water blockage but leading to more rapid local oxygen transport and charge conduction. The optimum performance improvement obtained using an MPL occurs in the moderate cathode humidification scheme (50%). A low-hydrophobicity CL tends to induce a large bulk oxygen transport resistance due to severe water flooding. An optimum hydrophobic electrode design is recommended to realize a tradeoff of oxygen and charge transport, which consist of a super-hydrophobicity gas diffusion layer (contact angle 120°), low-hydrophobicity MPL (contact angle 105°), and middle-hydrophobicity CL (contact angle 95°). • Detailed CL model considering more complex physic and geometry is proposed. • Dominating role of local oxygen, bulk oxygen, and charge transport is revealed. • MPL improves cell performance significantly at middle cathode humidification. • An optimum matching design for hydrophobic porous electrodes is recommended.

Performance evaluation on thermodynamics-economy-environment of PEMFC vehicle power system under dynamic condition

Proton exchange membrane fuel cell (PEMFC) has the merits of fast starting speed, zero pollution, high efficiency and high reliability, which is gradually applied to new energy vehicles. In this paper, a vehicle PEMFC power system model is established, which is mainly consisted of PEMFC stack, air compressor, hydrogen circulation pump, cooling water pump and humidifier. The influence of auxiliary equipment energy consumption on fuel cell power system efficiency and total system cost under dynamic conditions is studied. Moreover, the mapping relationship between operating parameters (operating temperature, inlet humidity of anode and cathode) and thermodynamic system performance (electrical power, electrical efficiency, thermal efficiency) is analyzed. The auxiliary equipment energy consumption and system thermal performance output of the vehicle PEMFC system model at the 180-300A step current is obtained. Furthermore, total system cost and pollutant emissions quality under transient response and dynamic operation are estimated. The results show that in a 30 kW vehicle PEMFC system model, the net output power of the system can reach 22.5 kW. The maximum electrical efficiency and thermal efficiency of the system reach 41 % and 52.1 %, respectively. After 2400 h operation, the total system cost reaches 62616$. Wind energy hydrogen production shows the lowest pollutant emission.

Performance Prediction of Alkaline Fuel Cell Via Gradient Boosting Algorithm

With the DFT theory at the forefront, non-PGM catalysts have begun to develop, and in much literature, results have shown that the performance of non-PGM catalysts is comparable to that of PGM catalysts. Jing et. al. synthesized Fe-Co dual sites on nitrogen-doped carbon for oxygen reduction reaction (ORR). (FeCo)/N-C had almost equal half-wave potential to commercial Pt/C.[1] Hanguang et. al. achieved high ORR-activated Fe-N-C catalysts by tuning the doped Fe content and active sites.[2] However, if both (FeCo)/N-C and Fe-N-C were applied to PEMFC, they were not comparable to PGM catalysts unlike in the results of the half-cell test. This discrepancy means that numerous factors should be considered and optimized in a practical system like a fuel cell. Besides, it is indicated that even if the DFT theory and deep-learning combine to suggest catalysts with high performance, it may not produce as much performance in the actual fuel cell system as expected.In this respect, the combination of fuel cell systems (not catalysts) and artificial intelligence (AI) seems more reasonable. Without human judgment or intervention, machine learning sets priorities between each index by learning from many databases.Herein, we newly developed an optimization model for alkaline liquid fuel cell (Hydrazine fuel cell) using gradient boosting algorithm (XGBoost) which is one of machine learning algorithms. We operated fuel cells in various conditions by changing humidity of cathode, back pressure of cathode, cell temperature, stoichiometric factor (air/fuel), and concentration of the fuel. And then, we categorized and classified with the specific algorithm. Finally, we re-organized and set as a function of weight which effects on fuel cell operation. We hope that these approach will help improve fuel cell performance by controlling a number of factors without human intervention.[1] J. Wang, Z. Huang, W. Liu, C. Chang, H. Tang, Z. Li, W. Chen, C. Jia, T. Yao, S. Wei, Y. Wu, Y. Li, J. Am. Chem. Soc. 139 (2017) 17281–17284.[2] H. Zhang, H.T. Chung, D.A. Cullen, S. Wagner, U.I. Kramm, K.L. More, P. Zelenay, G. Wu, Energy Environ. Sci. 12 (2019) 2548–2558.

Experimental Analysis on Flow Field Pattern of PEM Fuel Cells

The polymer electrolyte membrane (PEM) fuel cells flow fields channels serve the same roles as nutrient and reactant circulation systems in plants and animals, so bio-inspired flow field channels with a similar could improve reactant uniform transport efficiency and boost fuel cell performance. In this analysis, the lung channel configuration of a humane lung and a tree leaf bio-inspired flow field channels are used as an anode and cathode bipolar plate. A channel model is developed for three new flow field patterns designs: leaf design, lung design and triple-serpentine. It has been observed that the performance improvement in terms of power in the bio-inspired flow field is 13.32% more than the triple serpentine. This indicates the bio-inspired design has good performance than other flow field design. Further a parametric steady is carried out experimentally to study the effect of cell operating temperature, anode and cathode humidity, hydrogen and oxygen flow rate on the cell performance.

Supportless Pt-ionomer hybrid porous nanofibrous networks with self-regulated water management for polymer electrolyte fuel cells

Water management within the electrode architecture restrains the performance and dynamic stability of polymer electrolyte fuel cells (PEFCs), especially with the reduction of precious electrocatalyst loading. Local mass transport at the catalyst-ionomer interphase crucially depends on the water uptake of the ionomer layers, which could be optimized via balancing electrode flooding and draining during the dynamic change of current and humidification. Herein this work, supportless platinum-ionomer hybrid porous nanofibrous are constructed via a new method combined with electrospinning and electrochemical etching. Ascribing to the hierarchical architecture of continuous platinum-ionomer nano-dendrites and fibrous networks, only 17.8% maximum power density deviation under varied cathode humidity is observed in the porous nanofibrous cathode, compared to 160% deviation for traditional one. Such self-regulated water management within this electrode is achieved due to stable interfacial layer constructed under working circumstance. This presented work could provide alternative thoughts on mass transport issues affected by nanoscale interfacial structures and demonstrate an efficient design of electrode architecture with better performance and dynamic stability for polymer electrolyte fuel cells.

Fabrication of Catalyst Layers with Preferred Mass and Charge Transport Properties through Texture Engineering

Electrode structure strongly influences the charge and mass transport of energy conversion devices such as polymer electrolyte membrane fuel cells. Various studies have been carried out to optimize the nanoscale features and porosity of the electrode catalyst layer. The impact of large-scale texture, i.e., from several to tens of microns, was however much less investigated. In the present study, we demonstrated the fabrication of catalyst layers directly on the polymer electrolyte membrane with controlled texture by the ultrasonic spray coating technique. By controlling the droplet size of the catalyst ink as well as its drying behaviors, textured catalyst layers with enhanced mass or charge transport properties can be reproducibly obtained through the manipulation of micron-scale Marangoni flows. When the Marangoni effects are maximized, a heavily textured catalyst layer populated with large and deep pores exhibiting good mass transport properties is formed and shows a maximum current density of 1.75 A/cm2. With a slower drying rate of the catalyst ink, a much less textured but more loosely packed catalyst layer is obtained, which shows impressive charge transport properties even under low humidified conditions. With the mass transport resistance greatly alleviated, a maximum power density of 0.8 W/cm2 can be reached at a cathode humidity of 43% at 80 °C using a very low cathode Pt loading of 0.079 mgPt/cm2. Such high performance under low-humidity conditions can lead to significant cost reduction in fuel cell system and its operation.