新型燃料电池用质子交换膜研究进展

传统的全氟磺酸膜Nation、Dow质子交换膜、Flemion等目前在质子交换膜燃料电池中的应用最为广泛，但在高温条件下以氢或甲醇作为燃料的燃料电池中，其性能受到一定的影响，且这类膜价格昂贵，不利于推广应用，阻碍了燃料电池的商业化进程。因此，开发一种新型的价格低廉、性能良好的膜是推广应用此类电池的关键。本文简要介绍了目前各国研究的应用于高温条件下(100～160℃)质子交换膜燃料电池与直接甲醇燃料电池中的新型膜。对它们的质子传导率、甲醇渗透率等性能进行了分析比较。     

Fe-PPy-TsOH/C用作质子交换膜燃料电池氧电极催化剂的研究

氧电极催化剂是制约质子交换膜燃料电池(PEMFCs)发展和应用的一个重要因素, 开发低价高效的非贵金属催化剂对PEMFCs来说已成为当务之急。本研究选择氮掺杂的碳载过渡金属(M-N/C)类催化剂为研究对象, 以铁盐作为金属前驱体, BP2000为碳源, 聚吡咯(PPy)为氮源, 对甲基苯磺酸(TsOH)为掺杂剂, 合成了非贵金属催化剂Fe-PPy-TsOH/C, 探究了不同的热处理温度及钴原子的掺杂对其氧还原催化性能的影响。研究结果表明: 800℃制备的Fe-PPy-TsOH/C催化剂因结晶度高、颗粒大小适中且分布均匀而具有最佳的氧还原催化性能; 一定量的钴原子取代可以改善Fe-PPy-TsOH/C的氧还原催化性能, 当钴的掺杂量为33.33%时(铁钴原子比为2︰1), 催化剂的性能达到最优。     

硼氢化钠-质子交换膜燃料电池的研究发展趋势

对硼氢化钠-质子交换膜燃料电池的国内外近期研究进行了综述,重点分析了硼氢化钠水解制氢用催化剂的制备、性能、水解制氢副产品再生和硼氢化钠-质子交换膜燃料电池系统的装置设计,提出了多组分合金化与多孔结构化催化剂的研究思路,强调了硼氢化钠-质子交换膜燃料电池系统研制的必要性和迫切性.     

质子交换膜燃料电池的研究与应用进展

综述了质子交换膜燃料电池的研究及应用状况,并对影响其性能的因素进行了讨论,指出了今后的研究方向.     

燃料电池用质子交换膜的研究进展

质子交换膜是质子交换膜燃料电池(PEMFC)的和绝缘电子的作用,其性能和寿命直接决定电池的性能和寿命.从膜材料的角度分类,综述了质子交换膜燃料电池用主链含氟聚合物膜、元素有机聚合物膜以及芳香族碳氢化合物膜的特性和研究现状.     

In Situ and Operando Characterization of Proton Exchange Membrane Fuel Cells

For proton exchange membrane fuel cells (PEMFCs) to become a mainstream energy source, significant improvements in their performance, durability, and efficiency are necessary. To improve their durability, there must be a solid understanding of how the structural and electrochemical processes are affected during operation to propose mitigation strategies. To this aim, in situ and operando characterization techniques can locally identify structural and electrochemical processes, which cannot be captured using conventional techniques. Linking these properties in the same geometric area has been challenging due to its inherent limitations, such as sample size and imaging resolution. This has created a knowledge gap in structure‐to‐electrochemical performance relationships as operation and degradation unevenly affect different areas of the cell. In the recent past, catalyst layer degradation, hot spots, and water management have been structurally and electrochemically visualized in the same geometric area, revealing new interactions. To further the research in this direction, these interconnected fields are reviewed, followed by a roadmap for in situ characterization of PEMFCs, treating structural and electrochemical processes as a unified subject. With this approach, the knowledge of the degradation of PEMFCs will be significantly improved.     

中温燃料电池用质子交换膜的研究进展

Nafion(R) 等全氟磺酸膜由于寿命长,导电性能优越,长久以来一直应用于质子交换膜燃料电池中,但其价格昂贵,甲醇阻隔性能差,工作温度高于100℃后,导电性随着水的挥发流失而迅速下降.而解决燃料电池中催化剂一氧化碳中毒和提高燃料转化效率的有效办法是提高工作温度.能在中高温环境中工作的质子导电材料已成为研究热点之一.综述了近年来应用于中温质子交换膜燃料电池中质子导电膜的研究进展,并评述了非水体系和高温水汽体系.     

Nitrogen‐Coordinated Single Cobalt Atom Catalysts for Oxygen Reduction in Proton Exchange Membrane Fuel Cells

Due to the Fenton reaction, the presence of Fe and peroxide in electrodes generates free radicals causing serious degradation of the organic ionomer and the membrane. Pt‐free and Fe‐free cathode catalysts therefore are urgently needed for durable and inexpensive proton exchange membrane fuel cells (PEMFCs). Herein, a high‐performance nitrogen‐coordinated single Co atom catalyst is derived from Co‐doped metal‐organic frameworks (MOFs) through a one‐step thermal activation. Aberration‐corrected electron microscopy combined with X‐ray absorption spectroscopy virtually verifies the CoN₄ coordination at an atomic level in the catalysts. Through investigating effects of Co doping contents and thermal activation temperature, an atomically Co site dispersed catalyst with optimal chemical and structural properties has achieved respectable activity and stability for the oxygen reduction reaction (ORR) in challenging acidic media (e.g., half‐wave potential of 0.80 V vs reversible hydrogen electrode (RHE). The performance is comparable to Fe‐based catalysts and 60 mV lower than Pt/C ‐60 μg Pt cm^?2). Fuel cell tests confirm that catalyst activity and stability can translate to high‐performance cathodes in PEMFCs. The remarkably enhanced ORR performance is attributed to the presence of well‐dispersed CoN₄ active sites embedded in 3D porous MOF‐derived carbon particles, omitting any inactive Co aggregates.     

用于质子交换膜燃料电池的高活性、高稳定性PtIrFe/C三元合金催化剂

采用催化裂解法制备了多孔碳,将其作为催化剂载体,利用液相还原和真空热处理工艺制备出PtIrFe/C三元合金催化剂。采用X射线衍射、透射电子显微镜等手段对样品的结构形貌进行表征。使用电化学测试手段研究了不同热处理温度对其催化性能的影响。实验结果表明,热处理带来的合金化作用使催化剂的催化活性和耐久性得到了极大的提高。经过700℃热处理的样品,其面积比活性和质量比活性分别是传统商业Pt/C催化剂的3~4倍。     

质子交换膜燃料电池CCM的制备条件对其性能的影响

采用催化剂涂覆的膜(CCM)和碳纸扩散层组成质子交换膜燃料电池的膜电极.CCM采用直接喷涂的方法制备,研究了与直接喷涂技术相关的影响因素,包括催化层中Nafion的含量和分布、有机溶剂的种类、喷涂操作条件等.CCM的表面形貌和孔结构采用扫描电镜(SEM)方法表征,MEA的电化学特性通过单体PEMFC的I-V曲线进行评价.实验结果表明,在优化条件下制备的CCM膜电极的结构和性能有明显的改善.     

磺化SEBS质子交换膜的研究进展

燃料电池商业化的实现要求要有性价比高的质子交换膜,磺化SEBS以其低廉的价格、独特的微相结构、良好的力学性能和高的质子导电率正成为大家关注的焦点.着重评述了磺化SEBS质子交换膜近年来的研究进展,较为详细地讨论了其制备、微相结构、性能特点和改性后在直接甲醇燃料电池等方面的应用,并扼要阐述了其发展方向.     

Rational Design of Ultrathin Gas Barrier Layer via Reconstruction of Hexagonal Boron Nitride Nanoflakes to Enhance the Chemical Stability of Proton Exchange Membrane Fuel Cells

Hexagonal boron nitride (hBN) has great potential as a promising gas barrier layer in proton exchange membrane fuel cells (PEMFCs) as it shows high proton conductivity as well as excellent gas‐blocking capability. However, structural defects and mechanical damage during the transfer of the hBN layer and membrane swelling have limited the application of hBN sheets to PEMFCs. Here, an ultrathin gas barrier layer is successfully fabricated on a proton exchange membrane via reconstruction of mechanically exfoliated hBN nanoflakes using a direct spin‐coating process. The hBN‐coated layer effectively suppresses the gas crossover and inhibits the formation of reactive oxygen radicals in the electrodes without reducing the proton conductivity of the membrane. It is also demonstrated that the structural advantages of hBN‐coated gas barrier layers promise high performance of a unit cell even after a open‐circuit voltage (OCV) hold test for 100 h. Furthermore, through in‐depth postmortem analyses, a time‐dependent degradation mechanism of membrane electrode assembly under the OCV condition is rationally proposed.     

质子交换膜燃料电池电催化剂催化机理研究最新进展

简述了质子交换膜燃料电池(PEMFC)电催化剂研究发展的概况和催化机理研究的最新进展,并指出了PEMFC电催化剂的选择与设计应重点解决的理论指导问题.     

阴离子交换膜燃料电池阳极催化剂的研究进展

阴离子交换膜燃料电池(AEMFC)可使用非贵金属催化剂,且电极反应速率快。阳极催化剂的选择和制备对提高燃料氧化速率和燃料电池的电流密度及降低成本等有很大影响。本文从阴离子交换膜阳极催化剂的种类、制备方法,催化剂的载体等角度对阳极催化剂的研究现状进行分析。分析表明,在阳极催化剂中掺杂金属、金属氧化物或非金属氧化物,能充分发挥各元素的协同作用,从而提高催化剂的电催化性能;改进制备方法可以提高催化剂的比表面积,改变元素的分布。对催化剂载体进行改性以改善载体自身的孔径分布,提高比表面积和稳定性,或寻求导电性好、比表面积大、耐腐蚀的新载体材料(如SiC、Ti等),均可以提高催化剂的载量和催化剂在载体上的分散度等,从而提高阴离子交换膜燃料电池的性能。     

Integrating PGM‐Free Catalysts into Catalyst Layers and Proton Exchange Membrane Fuel Cell Devices

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.     

质子交换膜燃料电池用金属双极板表面改性的研究进展

双极板是质子交换膜燃料电池(PEMFC)的重要组成部分,起收集传导电流、分隔氧化剂和燃料以及支撑电池堆等作用,占整个电池质量和成本的很大比重。目前PEMFC双极板材料主要有石墨、金属及相关复合材料。与其他双极板相比,金属双极板因具有导电导热性好、机械强度高、易加工和成本低等优点而受到重视,但其面临腐蚀及表面层钝化影响电池性能等问题。为此,国内外研究者对金属双极板的表面改性开展了广泛的研究,并取得了很大进展。     

质子交换膜燃料电池用炭纸的制备

以改性酚醛树脂为粘合剂,炭纤维纸为坯体,通过浸渍、模压固化、炭化、石墨化工艺制得质子交换膜燃料电池气体扩散层用炭纸,表征了炭纸的基本性能并与东丽炭纸的相关性能进行了对比。结果表明,自制炭纸的厚度为0.189mm,密度为0.446g/cm3,均与东丽炭纸相近;孔隙率为83%,比东丽炭纸提高18.6%;体电阻率为3.35mΩ.cm,面电阻率为3.86mΩ.cm,分别比东丽炭纸减小了25.9%和39.7%;压差为88.2Pa时透气率达5100mL.mm/(cm2.h.mmAq),比东丽炭纸提高了41.67%;抗拉强度为29.98MPa,比东丽炭纸提高约16.5%;与东丽炭纸相比,自制炭纸的电压输出性能略有下降但不明显。     

质子交换膜燃料电池水管理动态模型研究

水管理是质子交换膜燃料电池取得良好性能的关键因素之一,膜中水的含量及其分布的不均匀造成了电池性能下降。限于试验条件及测试技术,为了更好地探明电池中水的行为及分布,研究者们开展了大量的数学模型和仿真模拟。从质子交换膜燃料电池的工作原理角度出发,回顾了有关质子交换膜中水传递从一维模型到三维模型的发展历程,并阐述了各个阶段研究的要点、限定条件和主要的研究成果。同时,提出了未来水管理方面数学模型和仿真模拟发展的新方向。模型的完善有利于燃料电池控制策略的研究,这将为电池的优化设计提供理论基础。