燃料电池聚合物电解质膜的研究进展

本文根据聚合物电解质膜燃料电池操作温度、使用的电解质和燃料的不同,将其分为高温质子交换膜燃料电池、低温质子换膜燃料电池、直接甲醇燃料电池和阴离子交换膜燃料电池,综述了它们所用电解质膜的最新进展.第一部分简要介绍了这4种燃料电池的优点和不足.第二部分首先介绍了Nafion膜的结构模型,并对平行柱状纳米水通道模型在介观尺度上进行了修正;接着分别对应用于不同燃料电池的改性膜的改性思路作了分析;最后讨论了用于不同燃料电池的新型质子交换膜的研究,同时列举了性能突出的改性膜和新型质子交换膜.第三部分介绍了阴离子交换膜的研究现状.第四部分对未来聚合物电解质膜的研究作了展望.     

有机-无机复合质子交换膜的制备与界面特性

有机-无机复合质子交换膜的开发是燃料电池用质子交换膜的一个重要研究方向,本文综述了有机-无机复合质子交换膜的制备方法,分析了两相之间的界面特性,并对这种复合膜的研究前景进行了展望.     

直接甲醇燃料电池用阻醇全氟磺酸复合质子交换膜

全氟磺酸膜(如杜邦公司生产的Nafion系列产品)作为质子交换膜广泛应用于直接甲醇燃料电池,但其存在着燃料甲醇渗透率高的缺陷,是阻碍直接甲醇燃料电池应用的主要问题之一。本文介绍了直接甲醇燃料电池用阻醇全氟磺酸复合质子交换膜的最新研究进展,比较了各类无机、有机添加物对复合膜甲醇渗透率、质子电导率以及电池性能的影响,并讨论了添加物对全氟磺酸质子交换膜甲醇、质子传递的影响机理。此外,针对大多数复合膜以牺牲质子电导来抑制甲醇渗透的问题,对如何提高复合膜质子对甲醇选择性及其未来发展趋势提出了一些设想。     

燃料电池用聚合物质子交换膜专利技术分析

聚合物质子交换膜是燃料电池的一个重要组成部分,也是目前研究的热点技术。本文对燃料电池用聚合物质子交换膜领域的专利申请状况进行了分析,从全氟型磺化聚合物质子交换膜、部分含氟型磺化聚合物质子交换膜和非含氟型磺化聚合物质子交换膜等3个方面出发,归纳出该技术领域的技术发展路线,并对该技术领域的发展做出展望。     

质子交换膜燃料电池膜电极耐久性的提升

质子交换膜燃料电池由于具有能量转换效率高、操作温度低、环境友好等优点而备受人们关注。随着2014年丰田发布燃料电池电动汽车Mirai,带来了新一轮燃料电池及燃料电池汽车的产业化热潮。然而,提升质子交换膜燃料电池的寿命,开发新一代长寿命燃料电池膜电极及燃料电池仍然是本领域的挑战性课题。膜电极(MEA)是质子交换膜燃料电池最核心的部件,其耐久性直接决定着燃料电池的寿命。MEA主要由质子交换膜、催化剂层、气体扩散层三部分组成。本文从质子交换膜、催化剂及载体、气体扩散层三个方面介绍了近年来国内外在提升燃料电池膜电极的寿命(耐久性)方面所做的工作,并对未来的相关研究和发展做了述评及展望。     

直接甲醇燃料电池中的膜性能比较

制备了磺化聚醚醚酮(SPEEK)和磺化酚酞型聚醚砜(SPES-C)两种质子交换膜,考察了其质子导电和阻醇性能.实验发现,两种新型质子交换膜具有一定的化学稳定性和质子电导率,尤其在高温下两种新膜的质子电导率与Nafion膜接近.两种新膜的甲醇透过系数要比Nafion膜的低1～2个数量级.分别以两种新型膜和Nafion115膜为电解质制备了直接甲醇燃料电池膜电极,讨论了膜材料的性能对直接甲醇燃料电池性能的影响.结果表明,膜材料的阻醇性越好,电池的开路电压越高;膜的电导率越高,在较高电流密度区域内电池的性能越好.     

直接乙醇燃料电池中乙醇电氧化过程的热力学和动力学考虑

从热力学和动力学角度讨论了质子交换膜燃料电池中的乙醇电氧化过程.理论计算得出直接乙醇燃料电池比乙醇重整质子交换膜燃料电池具有较高的有效能效率.从热力学分析可知,温度低于100℃时乙醇完全氧化的最大转化率仅为14%.从动力学角度考虑,PtSn/C催化剂对乙醇电氧化具有较高的催化活性,但仍不能使乙醇发生完全电氧化.热力学和动力学分析表明,操作温度是影响直接乙醇燃料电池性能的关键因素,它对开发新型催化剂和电解质膜材料提出了新的要求.     

车用质子交换膜燃料电池材料部件

车用燃料电池主要包括质子交换膜燃料电池、金属-空气燃料电池等,其中质子交换膜燃料电池是目前车用燃料电池的主要开发对象(以下简称车用燃料电池)。经过全球范围内近十年的持续研发,车用燃料电池在能量效率、功率密度与比功率、低温启动等功能特性方面已经取得了突破性进展,新一轮的燃料电池汽车产业化浪潮正在迫近。然而,车用燃料电池的耐久性和成本还没达到预期商业化目标,是其产业化的最后障碍。探索和研发燃料电池用新型关键材料部件是解决这两大问题、推进其商业化进程的关键所在,也是车用燃料电池长期的研究重点和热点。本文系统地梳理了近几年来车用燃料电池质子交换膜、催化层、气体扩散层、双板板关键材料部件的研究进展和成果,并分类进行了简要评述,分析了其性能与商业化目标的差距。最后展望了车用燃料电池关键材料部件今后的发展方向。     

质子交换膜的传输通道微观结构对燃料电池性能的影响

质子交换膜燃料电池因其高效、高能量密度、快速启动等独特优势在便携电子设备及汽车动力装置等应用中极具发展潜力。质子交换膜内的传输通道由于对膜质子传导性能有重要影响而受到研究者们的广泛关注。构筑有序结构的质子传输通道,能够获得质子电导率与燃料渗透率、热稳定性、化学稳定性等性能均衡提升的新型质子交换膜材料。本文结合近年来质子传输通道的研究进展,对控制聚合物的相形态从而构筑有序质子传输通道的研究进行了综述,并针对不同相形态所形成的有序通道对膜及燃料电池性能的影响进行了分类与评述,最后对其发展趋势进行了展望。     

磺化嵌段型共聚物在质子交换膜燃料电池中的应用

燃料电池是以碳氢化合物为燃料的一种新型、清洁的发电装置,而其中的质子交换膜燃料电池由于具有可快速启动的优点而可应用于机动车等领域。所用的质子交换膜需要具有高的质子传导性、低的甲醇/水渗透性、好的机械和热稳定性以及合适的价格等特点,但目前已经工业化的Nafion膜并未能全部满足上述要求。为了解决这些问题,目前已经开发了多种新的质子交换膜。本文对其中的磺化嵌段型聚醚砜、磺化嵌段型聚酰亚胺和苯乙烯基嵌段共聚物在质子交换膜燃料电池中的应用进行了综述,并与Nafion膜和相应的无规共聚物的性能进行了比较。最后展望了嵌段共聚物在质子交换膜领域的发展趋势。     

核-壳结构氧还原反应电催化剂

The high cost of platinum in catalyst layers hinders the commercialization of proton exchange membrane fuel cells. This Account reviews recent progress on core-shell nanostructures for oxygen reduction reaction (ORR) in acidic media, which is the cathodic reaction in fuel cells. The synthesis, characterization and evaluation of different types of core-shell electrocatalysts are summarized. Various strategies to improve the performance of core-shell electrocatalysts, including dealloying, morphology control, and surface modification are presented. The issues of mass production and fuel cell performance of core-shell electrocatalysts are also discussed.     

Effect of Anode Material on Electrochemical Oxidation of Low Molecular Weight Alcohols—A Review

The growing climate crisis inspires one of the greatest challenges of the 21st century—developing novel power sources. One of the concepts that offer clean, non-fossil electricity production is fuel cells, especially when the role of fuel is played by simple organic molecules, such as low molecular weight alcohols. The greatest drawback of this technology is the lack of electrocatalytic materials that would enhance reaction kinetics and good stability under process conditions. Currently, electrodes for direct alcohol fuel cells (DAFCs) are mainly based on platinum, which not only provides a poor reaction rate but also readily deactivates because of poisoning by reaction products. Because of these disadvantages, many researchers have focused on developing novel electrode materials with electrocatalytic properties towards the oxidation of simple alcohols, such as methanol, ethanol, ethylene glycol or propanol. This paper presents the development of electrode materials and addresses future challenges that still need to be overcome before direct alcohol fuel cells can be commercialized.     

Platinum Nanoparticles Modified with Perfluorinated Alkylamines as a Model Cathode Catalyst for Fuel Cells

Platinum nanoparticles (NPs) modified with undecafluorohexylamine (UFHA) and octylamine were synthesized as a novel model cathode catalyst for fuel cells. The modified Pt NPs were well characterized by FTIR, X‐ray photoelectron spectroscopy, thermogravimetric analysis, and transmission electron microscopy. These NPs supported on carbon black were applied as electrocatalysts for the oxygen reduction reaction. The UFHA‐modified Pt NP catalyst showed high electrocatalytic activity and durability compared to a commercial catalyst. Besides suppression of undesired oxide formation on the Pt surface, the affinity between the perfluorinated alkyl chains of UFHA and Nafion^® improved the catalyst activity by creating a desirable proton conduction path. Additionally, UFHA modification improved durability by suppressing Pt dissolution and carbon corrosion because of restricted water accessibility. The β ‐oxide formation, which is responsible for Pt dissolution, was significantly attenuated by surface modification.     

Development of Poly(Vinyl Alcohol)-Based Polymers as Proton Exchange Membranes and Challenges in Fuel Cell Application: A Review

Abstract

Poly(vinyl alcohol) (PVA) is a biodegradable, water-soluble membrane that has low methanol permeation and reactive chemical functionalities. Modification of these features makes PVA an attractive proton exchange membrane (PEM) alternative to Nafion^TM. However, the pristine PVA membrane is a poorer proton conductor than the Nafion^TM membrane due to the absence of negatively charged ions. Hence, modification of PVA matrixes whilst complying with the requirements of projected applications has been examined extensively. Generally, three modification methods of PVA membranes have been highlighted in previous reports, and these are (1) grafting copolymerization, (2) physical and chemical crosslinking, and (3) blending of polymers. The use of each modification method in different applications is reviewed in this study. Although the three modification methods can improve PVA membranes, the mixed method of modification provides another attractive approach. This review covers recent studies on PVA-based PEM in different fuel cell applications, including (1) proton-exchange membrane fuel cells and (2) direct-methanol fuel cells. The challenges involved in the use of PVA-based PEM are also presented, and several approaches are proposed for further study.     

Carbon Monoxide Oxidation on Pt Single Crystal Electrodes: Understanding the Catalysis for Low Temperature Fuel Cells

Herein the general concepts of fuel cells are discussed, with special attention to low temperature fuel cells working in alkaline media. Alkaline low temperature fuel cells could well be one of the energy sources in the next future. This technology has the potential to provide power to portable devices, transportation and stationary sectors. With the aim to solve the principal catalytic problems at the anode of low temperature fuel cells, a fundamental study of the mechanism and kinetics of carbon monoxide as well as water dissociation on stepped platinum surfaces in alkaline medium is discussed and compared with those in acidic media. Furthermore, cations involved as promoters for catalytic surface reactions are also considered. Therefore, the aim of the present work is not only to provide the new fundamental advances in the electrocatalysis field, but also to understand the reactions occurring at fuel cell catalysts, which may help to improve the fabrication of novel electrodes in order to enhance the performance and to decrease the cost of low temperature fuel cells.     

燃料电池用聚合物质子交换膜的研究进展

质子交换膜（PEM）是质子交换膜燃料电池的核心组件之一,具有隔绝阴阳极、提供质子传递通道和阻止燃料渗透的作用. 商业化应用的全氟磺酸PEM存在燃料渗透严重、高温条件下导电性差和成本高的问题,开发性能优良的聚合物PEM显得很有必要. 本文讨论了近年来聚合物PEM的研究进展,分别从聚合物的主链、支链和交联结构角度介绍了分子结构对薄膜相分离、质子导电性、稳定性和电池性能等性能的影响,并讨论了聚合物分子结构设计方面存在的问题,最后对燃料电池用聚合物PEM在未来的发展方向进行了展望.     

Single fuel cell with supported LSM cathode

Single fuel cells with bilayer supported cathodes are manufactured and tested. The cathodes consist of a high-porous La_0.6Sr_0.4MnO₃ support with the thickness of approximately 1 mm and a functional composite layer with the thickness of 13?C15 ??m made of La_0.75Sr_0.2MnO₃ and 8YSZ. Voltammetric and power characteristics of single fuel cells with a supported cathode, thin-film YSZ electrolyte, and platinum cathode are determined. The conclusion as to the significant contribution into the polarization overpotential losses on the cathode is made on the basis of the measurements of electric fuel cell characteristics. It decreases significantly as a result of the supported cathode modification by praseodymium oxide. At 850°C and voltage of 0.81 V, electric power density of a fuel cell was 1.65 W/cm².     

聚苯并咪唑的合成、性能及在燃料电池膜材料中的应用

讨论了聚苯并咪唑（PBI）的制备、种类及其性能，综述了围绕PBI用作质子导电材料的改性、掺杂及质子输送机理的研究进展，评述了PBI在质子交换膜中应用的进展。     

Boron-Doped PdCuAu Nanospine Assembly as an Efficient Electrocatalyst toward Formic Acid Oxidation

Control of the composition and morphology of Pd-based electrocatalysts is a promising strategy for the development of efficient direct formic acid fuel cells. Herein, a two-step method is presented for the design of B-doped PdCuAu nanospine assemblies (B-PdCuAu NAs) using NaBH₄ as the boron dopant. The boron content can be tailored easily by tuning the reaction time, and an optimal boron content is beneficial to promote the formic acid oxidation reaction. Such B-PdCuAu NAs exhibit superior mass and specific activities to commercial Pd black and PdCuAu NAs in alkaline solution. The excellent catalytic performance of B-PdCuAu NAs may arise from the increase in surface active sites and the electronic effect of boron modification. This work provides a facile synthesis of the B-doped metallic catalysts and highlights the boron modification in improving their performance as anode electrocatalysts for fuel cells.     

新型碳纳米材料在低温燃料电池催化剂中的应用

 碳纳米管及其衍生纳米碳材料是一种介于富勒烯与石墨之间的碳的存在形式,具有独特的电子性质. 碳纳米材料可与其表面负载的金属活性相产生一种特殊的载体-金属相互作用; 纳米管中电子转移的动力学行为极佳,并且其特殊的纳米级孔道结构有利于反应物及产物的传质,因此作为低温燃料电池催化剂载体备受关注. 综述了多种新型碳纳米材料如碳纳米管、碳纳米纤维、碳纳米盘、碳纳米角和碳纳米分子筛等在低温燃料电池催化剂中的应用,并对其存在的问题和可能的发展方向进行了讨论.