直接甲醇燃料电池研究进展

介绍了直接甲醇燃料电池的工作原理、研究现状及最新进展,认为直接甲醇燃料电池是目前较理想的燃料电池,有广阔的发展前景。     

质子交换膜燃料电池可视化研究进展

质子交换膜燃料电池(包括氢氧质子交换膜燃料电池和直接甲醇燃料电池)内的两相流动以及相应的水管理、气管理对燃料电池的性能和寿命有很大的影响,而可视化方法是研究流场槽道内两相流动非常重要的方法之一。可视化实验可以真实地展示气泡或液滴在流场槽道内的生成以及发展过程,有利于了解其进化机制,从而进一步优化气管理、水管理并提高电池性能。本文主要综述了质子交换膜燃料电池两极流场内两相流动的可视化研究进展,讨论了扩散层的润湿性以及扩散层内水的传递机理,还介绍了实现可视化的方法,并提出了可视化研究的不足及发展方向。     

聚丙烯酰胺固体凝胶膜中甲醇透过性能研究

采用膜扩散法，由示差折光仪在线测试了聚丙烯酰胺(PAAM)固体凝胶膜室温下甲醇透过系数。实验结果表明，随凝胶浓度的增加，PAAM固体凝胶膜的甲醇透过系数呈下降趋势；但在凝胶浓度一定的情况下，随凝胶中文链度的增加，PAAM固体凝胶膜的甲醇透过系数出现极小值。因此，PAAM固体凝胶膜在掺杂导电成分后可于直接甲醇燃料电池(DMFC)中作为阻醇电解质膜使用。     

聚钛硅氧烷的溶胶-凝胶合成及转变规律研究

以甲基三甲氧基硅烷和钛酸四丁酯为原料、甲醇为溶剂、盐酸为催化剂采用溶胶-凝胶法制备了含有杂原子钛的甲基硅树脂基体，借助傅立叶变换红外光谱研究了其特性。为了全面地了解该体系的溶胶-凝胶转相规律，我们分别做出了加水量为理论水解量30％、40％、50％时体系的转相相图，并将其转换为直角坐标以考察加水量、甲醇用量对相转变的影响a结果表明，选用反应条件为：甲醇用量大于70％、水用量小于40％、反应温度为50℃、盐酸用量为10％时，容易形成含钛量大于50％的溶胶状态的甲基硅树脂。     

直接甲醇燃料电池质子交换膜研究进展

直接甲醇燃料电池(DMFC)以其燃料来源丰富、储存方便、结构简单、安全等优点而日益受到广泛的关注。预计将在很多领域中能得到广泛的应用。过去,人们对DMFC做了很多研究,针对直接甲醇燃料电池中的质子交换膜(PEM)的阻甲醇性能方面的研究进展作如下评述。     

甲醇制氢的燃料电池技术及应用

以质子交换膜燃料电池为例 ,介绍了甲醇蒸汽重整、甲醇分解以及甲醇部分氧化重整制氢为燃料电池提供燃料的催化反应机理、反应条件、催化剂性能等 ,并提出了甲醇制氢的质子交换膜燃料电池的优越性及应用前景。     

C207铜基催化剂常压甲醇分解反应动力学(Ⅰ)本征动力学模型

在直流流动积分反应器中常压下研究了C207催化剂甲醇分解反应本征动力学。实验温度、气体组成与甲醇合成工业条件相接近。以实验測定数据应用改进高斯-牛顿法对动力学模型参数进行估值,获得甲醇分解反应本征动力学方程。     

电解重整式甲醇燃料电池系统

为解决直接甲醇燃料电池中甲醇氧化活性低及甲醇穿透问题,提出一种新型的电解重整式甲醇燃料电池系统。在系统中,高温电解重整器重整甲醇为常温燃料电池供氢,燃料电池的部分电能供给电解重整器使用。通过对系统的物料流、焓流、有效能流的分析,确定了系统中的不可逆因素。结果表明:电解重整器电压是影响系统效率的重要参数;升高重整器温度可以显著降低其电压,但必须采用合理的压力、甲醇溶液浓度以抑制甲醇溶液的蒸发,降低热量损失。与传统的直接甲醇燃料电池系统以及高温甲醇热重整联合质子交换膜燃料电池系统相比,该系统性能较高、结构紧凑。     

RuAg/TiO2-C催化剂的制备及对甲醇的电催化氧化性能

采用改性溶胶-凝胶法和水热合成法制备了C掺杂多孔纳米TiO2,以其为载体制备了一种RuAg/TiO2-C催化剂.采用XRD、TEM、EDS、XPS及电化学分析对催化剂的结构和性能进行了表征,测定了其对甲醇的电催化氧化性能.结果表明,RuAg的负载和C的掺杂提高了TiO2对甲醇的电催化性能,RuAg/TiO2-C对甲醇电...     

有机锆聚合物气凝胶的制备及光催化还原CO2

以2-氨基对苯二甲酸(NH2-BDC)为配体、四氯化锆为Zr4+源,采用溶胶-凝胶法制备了4种不同配体/金属离子物质的量比的气凝胶,并通过SEM、BET、FTIR、XPS、UV-Vis、荧光光谱等表征了材料的结构及光电性能.结果表明,这种气凝胶不仅具有大的比表面积与丰富的孔道结构,而且在氙灯照射下具有光电效应,可以在水中催化还原CO2生成甲醇.在300 W的氙灯照射下,研究了不同配体/金属离子物质的量比对光催化还原CO2的影响.结果表明,当气凝胶中n(NH2-BDC):n(Zr4+)的实际比例为1.10:1时,4 h光催化反应后甲醇产率为3.94 mmol/g-cat,催化转换频率(TOF)为2.29 h–1.相同催化反应条件下以NH2-UiO-66(Zr)为光催化剂,甲醇的产率为2.33 mmol/g-cat,TOF为1.80 h–1.此外,该气凝胶具有较好的光催化稳定性.     

Prediction of methanol and water fluxes through a direct methanol fuel cell polymer electrolyte membrane

Development of a direct methanol fuel cell (DMFC) mass flux model, using conventional transport theory, is presented and used to predict the fluid phase superficial velocity, methanol and water molar fluxes, and the chemical species (methanol and water) dimensionless concentration profiles in the polymer electrolyte membrane, Nafion^® 117, of a DMFC. Implementation of these equations is illustrated to generate the numerical data as functions of the variables such as the pressure difference across the membrane, methanol concentration at the cell anode, temperature, and position in the membrane.     

The role of under-rib convection in mass transport of methanol through the serpentine flow field and its neighboring porous layer in a DMFC

Numerical simulation of a direct methanol fuel cell (DMFC) operating under discharging conditions is challenged by the difficulties in modeling of complicated liquid-gas two-phase flows and coupled electrochemical kinetics. Under open-circuit conditions, the net electrochemical reactions in the DMFC anode cease, but, owing to the methanol concentration difference between the anode and cathode, the mass transport of methanol remains, creating a mass transport process of methanol in a single-phase liquid flow with no electrochemical reactions in the DMFC anode. Consequently, an accurate simulation of mass transport of methanol under such open-circuit conditions becomes possible. In this work, we performed a 3D numerical simulation of mass transport of methanol in the DMFC anode under open-circuit conditions and obtained the mass flux of methanol through the porous layer for different values of permeability. We also measured the mass flux of methanol permeation from the anode flow field to the cathode under open-circuit conditions. The comparison between the numerical and measured mass flux of methanol made it possible to in situ determine the permeability of the typical commercial porous layer. Using this in situ determined permeability, we then investigated numerically the effect of methanol feed rates on mass transport and found that the in-plane under-rib convection plays an important role, even at low methanol feed rate, to make the reactant evenly distributed over the entire catalyst layer.     

Two‐Phase 1D+1D Model of a DMFC: Development and Validation on Extensive Operating Conditions Range

A two‐phase 1D+1D model of a direct methanol fuel cell (DMFC) is developed, considering overall mass balance, methanol transport in gas phase through anode diffusion layer, methanol and water crossover. The model is quantitatively validated on an extensive range of operating conditions, 24 polarisation curves. The model accurately reproduces DMFC performance in the validation range and, outside this, it is able to predict values under feasible operating conditions. Finally, the estimations of methanol crossover flux are qualitatively and quantitatively similar to experimental measures and the main local quantities' trends are coherent with results obtained with more complex models.     

Functionalization of polymeric materials as a high performance membrane for direct methanol fuel cell: A review

A coherent review on the advanced proton exchange membranes (PEMs) for direct methanol fuel cell (DMFC) application and the future direction in the development of a high performance polymeric membrane for DMFC were discussed in this paper. PEMs have a profound influence on performance of DMFC. The PEMs are categorized into five groups which are partially fluorinated, perfluorinated ionomers, acid–base complexes, non-fluorinated ionomers, hydro carbon and aromatic polymers. Many researchers have investigated the functionalization methods on the PEMs to solve methanol crossover problem while obtaining low electronic conductivity, high proton conductivity, low electro osmotic drag coefficient, high mechanical properties and good chemical and thermal stability. Including in this review, fabrication of PEM using electrospinning process coupled with the promising functionalized polymeric materials which were known to be the most important initiatives at present in order to further expand the full potential of DMFC performance.     

直接甲醇燃料电池

介绍了直接甲醇燃料电池的原理、结构,并与发展较早的氢气燃料电池进行优劣比较。针对近期商业化便携式燃料电池的技术指标,主要讨论了直接甲醇燃料电池在性能和成本上的现状和问题,并着重阐述了阳极催化剂和电解质膜(决定其性能的两个关键因素)的研发进展。     

直接甲醇燃料电池

介绍了直接甲醇燃料电池的原理、结构,并与发展较早的氢气燃料电池进行优劣比较。针对近期商业化便携式燃料电池的技术指标,主要讨论了直接甲醇燃料电池在性能和成本上的现状和问题,并着重阐述了阳极催化剂和电解质膜（决定其性能的两个关键因素）的研发进展。     

直接甲醇燃料电池技术及应用

本文回顾了直接甲醇燃料电池（ＤＭＦＣ）的研究开发历史,系统阐述了ＤＭＦＣ系统中电催化剂选择与设计基本原则、电解质膜材料与甲醇渗透的关系。分析了电池工作温度、工作压力和甲醇进料方式对ＤＭＦＣ电化学性能的影响。     

直接甲醇燃料电池用阻醇质子交换膜研究进展

直接甲醇燃料电池是近十年兴起的新型燃料电池,并以其独特的优点引起了人们广泛的关注。作为其重要组成部分的质子交换膜的性质是影响电池性能的关键因素。本文在介绍近两年质子交换膜研究最新进展的基础上,综述了天然聚合物用作质子交换膜材料的研究情况,并分析了其优劣势及应用前景。     

微型直接甲醇燃料电池阳极传质分析

针对微型直接甲醇燃料电池,将阳极流场板简化为规则结构的多孔介质,运用多孔介质理论建立了包括流场板在内的阳极传输模型。模型考虑了阳极流道内液体饱和度沿流动方向的变化、催化层的厚度以及甲醇渗透,计算并讨论了阳极流道内液体饱和度的分布和流量对电池电流密度的影响,分析了阳极过电位对甲醇浓度分布和电池性能的影响以及质子交换膜内的传质特性。     

Cell performances of direct methanol fuel cells with grafted membranes

Cell performances were evaluated with grafted polymer membranes as an electrolyte for a direct methanol fuel cell (DMFC). The membranes were prepared using a poly(ethylene-tetrafluoroethylene), or ETFE, film. The base polymer film was added to sulfonic groups using γ-radiation activated grafting technique as ion-exchange groups. These membranes had more suitable properties for DMFCs, i.e. higher electric conductivity and lower methanol permeability than perfluorinated ionomer membrane (Nafion). Nevertheless, the cell performance with the grafted membrane was inferior to that with Nafion. The analysis of electrode potentials vs. reversible hydrogen electrode showed larger activation overpotential for both the electrodes on the grafted membranes. We concluded that this is due to poor bonding of the catalyst layers to the grafted membranes.