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为实现质子交换膜燃料电池的高性能(高功率密度或大电流密度)、低成本(低铂载量)、长寿命发电,人们尝试在燃料电池的核心部件膜电极结构中引入梯度化设计的概念。梯度化膜电极包括膜电极中各组件的梯度化:气体扩散层的PTFE含量与孔隙率的梯度化,催化层的催化剂与Nafion用量的梯度化以及微孔层的疏水性与孔隙率的梯度化。梯度化膜电极中催化剂分布、孔隙率分布、亲/疏水性分布合理,具有良好的三相反应界面以及质子、电子、反应气体、水等多相物质高效传输通道,从而能满足在低铂载量、低加湿以及高电流密度条件下高性能稳定工作。本文整理了近几年来有关燃料电池梯度化膜电极研究的相关文献,梳理了梯度化膜电极研究发展脉络,归纳总结了各种梯度化膜电极的制备方法、性能以及构效关系,并展望了梯度化膜电极下一步研究方向,对高性能、低成本、长寿命的燃料电池开发具有指导意义。 相似文献
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In real catalyst systems, it is difficult to establish a correlation between catalytic properties and the shape (crystal planes, corners and steps) of the active catalytic particles. In this paper we present a clear shape dependence of the catalytic properties of a Vulcan‐supported fuel cell catalyst having 4 nm cubo‐octahedral platinum(0) nanocrystallites with (111) and (100) surfaces stabilized by sodium polyacrylate. The electrode materials were characterized by CO‐stripping cyclic voltammetry and transmission electron microscopy (TEM), showing that no agglomeration had occurred among the nanoparticles on the catalyst surfaces. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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Automotive proton exchange membrane fuel cell stacks need to meet manufacturer specified rated beginning-of-life (BOL) performance before being assembled into vehicles and shipped off to customers. The process of “breaking-in” of a freshly assembled stack is often referred to as “conditioning.” It has become an intensely researched area especially in automotive companies, where imminent commercialization of fuel cell electric vehicles (FCEVs) demands a short, energy- and cost-efficient, and practical conditioning protocol. Significant advances in reducing the conditioning time from 1 to 2 days to as low as 4h or less, in some cases without the use of additional inert gases such as nitrogen, and with minimal use of hydrogen, and specialized test stations will be discussed. 相似文献
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We studied the influence of CO poisoning of the anode in the polymer electrolyte membrane fuel cell (PEMFC) using electrochemical impedance spectroscopy (EIS). The anode impedance was found by first feeding neat hydrogen gas and next hydrogen with CO into one of the electrodes, keeping neat hydrogen gas on the other electrode as a reference. The electrodes were E-TEK Elat gas-diffusion electrodes with 0.5 mg Pt/cm2, and the membrane was Nafion® 117. The CO concentration was 103 ppm, and the total pressures were 1, 2.5 and 4 bar. Operating temperatures were kept constant, 30.0 °C or 50.0 ± 0.1 °C. Bias voltages of 0 and 0.05 V were used. Three steps were revealed in the reaction mechanism, the slow adsorption/diffusion step, the charge transfer step and the proton hydration step, confirming earlier results. Carbon monoxide affects the charge transfer step by blocking active sites and by affecting the surface polarisation. We further conclude that CO adsorbs to the porous carbon matrix, and reduces significantly the rate of surface diffusion of hydrogen to the surface. 相似文献
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The study on the dynamic response performance of PEMFC with electrodeposited RuO_2·xH_2O-Pt/C electrode 下载免费PDF全文
Dynamic response performance of proton exchange membrane (PEM) fuel cells affects its durability and reliability significantly. In this study, electrodeposited RuO2 xH2O-Pt/C was prepared to promote the PEM fuel cell dynamic response performance. The prepared RuO2 xH2O-Pt/C was characterized by scanning electron microscopy (SEM) equipped with energy disperse spectroscopy (EDS), which shows that RuO2 xH2O was electrodeposited on the surface of Pt/C. Performance of single cells with and without RuO2 xH2O-Pt/C at the cathode under a certain operating condition was studied using cyclic voltammetry, electrochemical impedance spectra (EIS) and polarization curve techniques. When the fuel cell modified with RuO2 xH2O-Pt/C was operated at lower pressure, a faster and more stable dynamic response could be found. Modifying with RuO2 xH2O-Pt/C composite material not only slightly increases the single cell performance but also dramatically improves the dynamic response performance, revealing that RuO2 xH2O-Pt/C can buffer the voltage undershoot whenever the current increases instantly. 相似文献
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Shangwei Zhou Paul R. Shearing Dan J.L. Brett Rhodri Jervis 《Current Opinion in Electrochemistry》2022
Proton exchange membrane fuel cells are considered a promising power supply system with high efficiency and zero emissions. They typically work within a relatively narrow range of temperature and humidity to achieve optimal performance; however, this makes the system difficult to control, leading to faults and accelerated degradation. Two main approaches can be used for diagnosis, limited data input which provides an unintrusive, rapid but limited analysis, or advanced characterisation that provides a more accurate diagnosis but often requires invasive or slow measurements. To provide an accurate diagnosis with rapid data acquisition, machine learning methods have shown great potential. However, there is a broad approach to the diagnostic algorithms and signals used in the field. This article provides a critical view of the current approaches and suggests recommendations for future methodologies of machine learning in fuel cell diagnostic applications. 相似文献
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In this work, the self-adaptive characteristics of self-humidifying air-cooled PEMFC stack was investigated.The performance and the unit-cell voltage distribution of the stack were measured and analyzed through the unit-cell I-V curve fitting.The operating conditions for this experimental study were set as follows: hydrogen pressure at the anode was 2 bar, the fan power used for the react ant oxygen feed and stack cooling was at 0.3 W, and the duration and time gap of water purged from hydrogen chamber were 1 s and 10 s, respectively.The experimental results showed that the self-humidifying air-cooled PEMFC stack used for this work could be in stable operation with a certain fan power, e.g., 0.3 W, at self-adaptive mode without the requirement of external control circuit.The unit voltage distribution of the air-cooled PEMFC stack was highly affected by the load current.Under the operation with higher current density, the unit-cell voltage distribution of the stack was less uniform due to the difference in the internal resistance of the unit-cells and the excessive temperature existed in the stack.Based on the data analyses, an approximate exponential relationship was found between the voltage fluctuation rate and the load current density. © 2018 Chinese Chemical Society. All rights reserved. 相似文献
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质子交换膜燃料电池的核心部件--膜电极经历了两代传统制备方法后,已经进入第三代有序化膜电极发展阶段.有序化膜电极包括质子导体有序化膜电极和电子导体有序化膜电极两大类,而电子导体有序化膜电极包括催化剂材料有序化膜电极和催化剂载体材料有序化膜电极.有序化膜电极具有良好的电子、质子、水和气体等多相物质传输通道,从而可以大大降低膜电极中Pt载量、提升燃料电池的发电性能和延长燃料电池寿命.本文整理了近几年有关有序化膜电极的研究报道,梳理了有序化膜电极研究进展,归纳比较了各种有序化膜电极制备方法的优缺点,对未来高性能、低成本和长寿命的膜电极制备技术开发具有指导意义. 相似文献