锆酸钙基高温质子导体材料

锆酸钙基材料具有优良的热、机械、发光、介电性能,是先进的耐火、发光、铁电材料。自1991年Iwahara等发现锆酸钙基材料在高温下具有质子导电性以来,锆酸钙基电解质陶瓷的研究取得重大进展。本文结合本实验室的研究分别从材料制备、陶瓷烧结、质子传输机理及影响质子传输的因素等4个方面就20年来锆酸钙基质子导体材料的研究进展进行了综述,并对其未来发展进行了展望。     

新型氧离子导体La_2Mo_2O_9

La2Mo2O9是一种具有高离子导电性的新型氧离子导体,其氧离子电导率在1073K时高达0.06S/cm,与YSZ在1273K时的电导率相当。这种高的离子导电性使它在中温固体氧化物燃料电池、氧传感器、透氧膜、固态离子器件等领域有着重要的潜在应用前景。本文从La2Mo2O9的结构、性质、氧离子扩散机理及其掺杂改性4个方面综述了近年来La2Mo2O9基固体电解质的研究热点和新进展,为该固体电解质材料的研究提供了有价值的信息。     

SrCe0.9Yb0.1O3-α陶瓷的导电性

以高温固相反应法合成了质子导电性氧化物陶瓷SrCe0.9Yb0.1O3-α.粉末XRD结果表明,该陶瓷样品为单一斜方相钙钛矿型结构.以陶瓷样品为固体电解质、多孔性铂为电极,采用交流阻抗谱技术和气体浓差电池方法分别测定了样品在600～1000 ℃下、干燥空气及湿润氢气中的电导率及离子迁移数,研究了样品的离子导电特性.结果表明,在600～1000 ℃下干燥空气中,陶瓷样品的最大电导率为0.026 S·cm-1,氧离子迁移数为0.03～0.2,是一个氧离子与空穴的混合导体;在湿润氢气中,陶瓷样品的最大电导率为0.015 S·cm-1. 600～800 ℃时,陶瓷样品的质子迁移数为1,是一个纯的质子导体,而在900～1000 ℃时,陶瓷样品的质子迁移数为0.91～0.97,是一个质子与电子的混合导体,质子电导占主导.     

Ba_xCe_(0.8)Y_(0.2)O_(3-α)固体电解质的氧离子导电性

固体电解质是指固体状态下具有较高电导率的离子导体,根据其传导离子所带电荷分为阳离子导体(如:Na+,Li+,H+等)和阴离子导体(如:F-,Cl-,O2-等)。固体电解质与液体电解质不同之处为:(1)是固态;(2)电荷载流子通常只有一种;(3)由于晶格能较大,通常在较高温度下离子才能迁移。具有实用价值的固体电解质的电导率一般在10-3S·cm-1以上,同时要求其离子迁移数要足够大。至今,已发现和合成了上百种固体电解质材料。在加速研制绿色化学电源、寻找高离子电导率、高化学稳定性、低成本的固体氧化物燃料电池(SOFC)固体电解质的研究中,ABO3钙钛矿型…     

一种新型结构质子交换膜的研究

质子导体的研究近年来受到了广泛的关注，具有质子传导能力的电解质材料可广泛地应用于燃料电池、电解池、电化学反应装置以及传感器等领域，特别是作为质子交换膜燃料电池（PEMFC）的核心组件之一的质子交换膜越来越受到人们的重视。Nafion（Du Pont）全氟磺酸膜是目前广泛用于PEMFC中的一种质子导体。Nafion全氟磺酸膜具有优异的化学稳定性以及在较低温度条件下高的质子电导率，然而其高昂的价格、差的高温性能以及用于直接甲醇燃料电池（DMFC）中时的高甲醇渗透率阻碍了DMFC商业化发展。     

SrCe0.95 Yb0.05 O3-α的制备及其质子导电特性

利用固相反应法制备出固态质子导体SrCe0.95Yb0.05O3-α,并使用X射线衍射分析法及低频阻抗测量法对其电子结构和导电特性进行了研究.X射线分析结果表明,该物质为钙钛矿晶体结构,具有p型电子空穴和氧离子空穴.在低温下主要为电子导电,且电子导电率随温度的升高而增大.在含氢气环境中,当温度高于550 K时, SrCe0.95Yb0.05O3-α具有明显的质子导电性,随着温度的升高,质子导电性增强.当温度高于800 K时,质子是导体中的主要载流子,质子电导率可达4.5 mS/cm.     

固体电解质质子导体的研究进展

介绍了固体电解质质子导体的应用、结构、质子传输机理以及国内外的最新研究进展,详细地综述了钙钛矿型和非钙钛矿型固体电解质质子导体的多种结构类型以及其质子传导机理的最新理论研究,同时分别介绍了两种质子导体的发展概况和面临问题,展望了未来质子导体的发展前景.     

质子导体BaCe_(0.8)Lu_(0.2)O_(3-α)的电性能(英文)

采用高温固相法制备了BaCe0.8Lu0.2O3-α质子导体。运用X射线衍射仪(XRD)、扫描电镜(SEM)对该材料的物相结构、微观形貌进行了表征。在500~900℃温度范围内,应用交流阻抗谱和气体浓差电池方法研究了材料在不同气体气氛中的离子导电性和氢-空气燃料电池性能。结果表明,BaCe0.8Lu0.2O3-α材料为单一斜方晶结构,具有良好的致密性。在500~900℃温度范围内,干燥或湿润的氮气、空气和氧气中,材料的电导率随着氧分压增大稍有增大。在湿润的氢气中,材料表现为纯的质子导电性。在以该材料为固体电解质的氢-空气燃料电池条件下,材料表现为质子、氧离子和电子的混合导电性,其中离子导电性始终占主导;氢-空气燃料电池在900℃下的最大输出功率密度为92.2mW·cm-2,高于我们以前报道的BaCe0.8RE0.2O3-α(RE=Pr,Eu,Ho,Er,等)材料。     

Ba0.9La0.1Ce0.9Nd0.1O3-α陶瓷的离子导电性

用高温固相反应法制备了Ba0.9La0.1Ce0.9Nd0.1O3-α质子导电性陶瓷,粉末X-射线衍射(XRD)分析表明,该陶瓷为单一钙钛矿型斜方晶结构。在500~900℃温度范围内,分别用气体浓差电池方法和交流阻抗谱技术研究了材料在不同气体气氛中的离子导电性,并与Ba0.9Ca0.1Ce0.9Nd0.1O3-α材料的离子导电性进行了比较。结果表明,在500~900℃温度范围内、湿润氢气中,Ba0.9La0.1Ce0.9Nd0.1O3-α材料的质子迁移数为1,是一个纯的质子导体。在干燥空气中,该材料是一个氧离子和电子空穴的混合导体,氧离子迁移数为0.295~0.081,氧离子电导率高于Ba0.9Ca0.1Ce0.9Nd0.1O3-α。在湿润空气中,该材料是一个质子、氧离子和电子空穴的混合导体,质子迁移数为0.151~0.009,氧离子迁移数为0.300~0.107,质子电导率低于Ba0.9Ca0.1Ce0.9Nd0.1O3-α材料。在氢-空气燃料电池条件下,Ba0.9La0.1Ce0.9Nd0.1O3-α材料是一个质子、氧离子和电子的混合导体,离子迁移数为0.964~0.853,离子电导率与Ba0.9Ca0.1Ce0.9Nd0.1O3-α材料相近。     

新颖无机质子传导材料的研究进展

质子传导在燃料电池、气体传感及电致显色等领域有重要的研究前景.尤其是在燃料电池领域,由于其具有低污染、高效率、操作简单和寿命长等优点而被广泛应用.本文介绍了质子传导在质子交换膜燃料电池中的重要作用及工作原理,分析了质子交换膜的质子传导机理,并简要分析总结了近年来关于无机及其复合质子导体材料的研究进展.     

介孔材料离子导电性的研究

介孔材料由于其奇特的性质和广泛的应用成为人们研究的热点。本文介绍了近几年来介孔材料质子和锂离子导电性的研究现状和发展趋势,主要总结了介孔纯氧化物、介孔纯氧化物的孔内修饰、介孔氧化物的孔壁掺杂修饰、介孔氧化物薄膜、介孔材料与有机高分子复合膜的离子导电性的研究进展。     

硅材料在微型燃料电池中的应用*

微型燃料电池被认为可作为便携式电子设备的下一代电源而越来越受到关注。传统的石墨、金属等材料用于微型燃料电池时产生了不少问题,如石墨材料微加工性能差,金属易腐蚀、密度较大等不利于应用于便携式设备。硅材料因为其低的气体透过率、高的导热系数和适于微加工等特性在微型质子交换膜燃料电池中得到了越来越多地应用。本文对硅材料在微型燃料电池的气体扩散层、质子交换膜构造中的应用以及硅材料作为基底制作微型燃料电池技术的进展进行了综述,并对硅材料在微型燃料电池领域应用的技术特点及前景做了分析与讨论。     

微生物燃料电池

微生物燃料电池 (Microbial Fuel Cells,MFCs) 是一种利用微生物作为催化剂,将燃料中的化学能直接转化为电能的装置。本文首先简要介绍了MFCs 的发展简史和基本原理,针对MFCs 产电性能低的现状,分别从产电微生物、电池结构、质子交换膜(PEM)、电极以及电解液等方面着重综述了近几年有关提高MFCs 产电性能的研究进展。最后介绍了关于MFCs 的另一些有趣的研究方向：植物MFCs,生物阴极MFCs,以及污水脱氮和有毒废水处理。     

Latest Developments in Proton Conductors

Solid proton conductors are receiving considerable attention, stimulated by the need of pollution control and with the objective to develop future microprotonics. The latest striking developments in the study of proton conductors are presented:

• i)Hydrogen containing perovskites, with a discussion of the nature and location of hydrogen inprotonic and electronic high-temperature superconductors;
• ii)Novel forms of hydrogen in disordered and mixed conductors, with the problems of the vibrational proton transfer assistance assumed by some authors and the independent proton dynamics evidenced by inelastic neutron scattering;
• iii)Frequency dependent conductivity and dielectric relaxation, including thermally stimulated current experiments in hydrated synthetic and biological gels (seeds);
• iv)Proton conducting membranes as candidates to replace Nafion®-like materials in H₂ (methanol) fuel cells.

     

磺化聚醚砜/磷酸硼复合质子交换膜的制备与性能

采用sol-gel法成功制备了一系列有望用于高温质子交换膜燃料电池的新型磺化聚醚砜(SPES)/磷酸硼(BPO4)复合膜, 并经热重分析(TGA)-傅立叶变换红外光谱(FTIR)联用技术、差示扫描量热仪(DSC)、扫描电子显微镜(SEM)等对膜的结构和性能进行了表征. 结果表明, 复合膜较纯SPES膜具有更高的热稳定性和玻璃化转变温度, 较低的溶胀性及较高的氧化稳定性; SEM图片显示BPO4在聚合物基体中的分布十分均匀, 这将有利于连续质子传输通道的形成; 复合膜的质子传导率随BPO4含量的增加而增加, 当温度超过120 ℃后, 复合膜仍保持着较高的质子传导率, 这表明该复合膜在高温质子交换膜燃料电池中具有良好的应用前景.     

Evaluation of proton conductivity of sulfonated polyimide/dihydroxy naphthalene charge‐transfer complex hybrid membranes

Sulfonated polyimide (SPI)/dihydroxynaphthalene (DHN) charge‐transfer (CT) complex hybrid films were investigated as possible alternative for polymer electrolyte membranes in polymer electrolyte fuel cells. SPI/DHN CT complex hybrid films include CT complexes, which might work as electronic conductors, and sulfonic acid units, which could work as proton conductors. Therefore, the origin of the conductivity of SPI/DHN complex hybrid films was evaluated by four‐probe impedance measurements in the through‐plane direction of the films. The obtained conductivity of the CT complex hybrid films increased with the increase of ion exchange capacity of the CT films and the decrease of CT complex concentration in the films. These results indicated that proton transfer dominantly occurred in the CT complex hybrid films. Proton conductivity of the CT complex hybrid films consisting of 2,6‐ or 1,5‐DHN showed the similar values, although the molecular geometries of the CT complex were different. The activation energy values for proton conductivity in the CT films were approximately the same as that of Nafion 212. Water uptake (WU) results were also conducted and suggest that CT complex formation could control the degree of WU of the films and prevent dissolution of SPI. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2991–2997     

静电纺丝纳米纤维在燃料电池质子交换膜中应用的研究进展

保护环境,开发环保型能源,对人类和社会具有重要意义。 质子交换膜燃料电池由于具有燃料转化率较高和无污染的优点,备受关注。 静电纺丝纳米纤维具有比表面积大、高孔隙率和三维的相互连通的网状结构等特点,可以在燃料电池质子交换膜中得到广泛应用。 静电纺丝纳米纤维类复合质子交换膜具有较高的质子传导率,较低的燃料渗透率,较好的化学稳定性能、热稳定性能和机械性能。 本文首先介绍了质子交换膜燃料电池,然后从不同的离子型聚合物基质复合质子交换膜的类别出发,介绍了静电纺丝纳米纤维在Nafion、磺化聚酰亚胺(SPI)、聚苯并咪唑(PBI)、磺化聚醚醚酮(SPEEK)等不同种类的离子型聚合物质子交换膜中的研究现状及作用机理,同时对静电纺丝纳米纤维在质子交换膜的应用方面存在的问题及应用前景做了评论和展望。     

Thermally Stable Super Ionic Conductor from Carbon Sphere Oxide

A highly stable proton conductor has been developed from carbon sphere oxide (CSO). Carbon sphere (CS) generated from sucrose was oxidized successfully to CSO using Hummers’ graphite oxidation technique. At room temperature and 90 % relative humidity, the proton conductivity of thin layer CSO on microsized comb electrode was found to be 8.7×10^?3 S cm^?1, which is higher than that for a similar graphene oxide (GO) sample (3.4×10^?3 S cm^?1). The activation energy (E_a) of 0.258 eV suggests that the proton is conducted through the Grotthuss mechanism. The carboxyl functional groups on the CSO surface are primarily responsible for transporting protons. In contrast to conventional carbon‐based proton conductors, in which the functional groups decompose around 80 °C, CSO has a stable morphology and functional groups with reproducible proton conductivity up to 400 °C. Even once annealed at different temperatures at high relative humidity, the proton conductivity of CSO remains almost unchanged, whereas significant change is seen with a similar GO sample. After annealing at 100 and 200 °C, the respective proton conductivity of CSO was almost the same, and was about ～50 % of the proton conductivity at room temperature. Carbon‐based solid electrolyte with such high thermal stability and reproducible proton conductivity is desired for practical applications. We expect that a CSO‐based proton conductor would be applicable for fuel cells and sensing devices operating under high temperatures.     

High Ionic Conductivity in a LiFeO2–LiAlO2 Composite Under H2/Air Fuel Cell Conditions

New ionic conducting materials for electrolytes for electrochemical devices have been attracting the interest of researchers in energy materials. Here, for the first time, we report a conductive composite with high ionic conductivity derived from an electronic conductor α‐LiFeO₂ and an insulator γ‐LiAlO₂. High conductivity was observed in the α‐LiFeO₂–γ‐LiAlO₂ composite when prepared by a solid state reaction method. However, the conductivity enhancement in α‐LiFeO₂–γ‐LiAlO₂ composite was not observed when the two oxides were mechanically mixed. The α‐LiFeO₂–γ‐LiAlO₂ composite also exhibits O^2? or/and H⁺ ionic conduction which was confirmed through H₂/air fuel cell measurements. An exceptionally high conductivity of 0.50 S cm^?1 at 650 °C was observed under H₂/air fuel cell conditions. This provides a new approach to discover novel ionic conductors from composite materials derived from electronic conductors.     

Proton transfer in electrochemically active “solid hydroxide proton conductor-hydrogenated metal” heterostructures

The electrochemical activity of solid-state heterostructures containing a hydrogenated metal and a solid proton conductor is investigated in the temperature ranges of 360–458 K, 360–370 K, and 320–420 K. The eutectics KOH/NaOH or KOH/KOH · H₂O and the chemical compound KOH · H₂O were chosen as the proton conductor. The conductivity of these electrolytes is higher than 1 mS/cm and their activation energies lower than 0.4 eV. Proton conductivity of the electrolytes is established by the emf method and confirmed by the isotope effect (H?D) in the conductivities of KOH · H₂O and the high-temperature form of KOH/NaOH (the protium forms are ≈1.4 times higher). Anomalies in the temperature dependence of conductivity and heat capacity are characteristic of eutectics in the region of 360 ± 1 K, and this has an effect on the electrochemical properties of the PdH _x |KOH/NaOH|PdO _y and TiH _x |KOH · H₂O|C heterostructures. Transport of atomic particles of hydrogen—most likely protons—across (Pd/Ti)H _x |MOH heteroboundaries where MOH = KOH · H₂O, KOH/NaOH, KOH/KOH · H₂O has a reversible character, which is shown by isotope and impedance measurements. The importance of the self-organized microheterogeneous solid eutectics KOH/NaOH and KOH/KOH · H₂O for their high conductivity compared to NaOH, KOH, and KOH · H₂O taken individually is discussed.