200W MCFC电池组的电化学性能及热平衡计算

MCFC电池组 (6对电池 ,电极面积 2 2 6cm2 )在 0 .9MPa/cm2 反应气压下 ,输出功率为2 17.6W .热平衡计算表明 ,该电池组在 30 0mA/cm2 电流密度下放电 ,当气体利用率为 2 0 %时 ,电池组处于热平衡状态下运行 .若维持此热平衡 (电池组内最高温度为 70 0℃ ,运行温度 6 5 0℃ )状态且提高反应气体利用率 ,则电池组热平衡点的电流密度将下降 ,以空气 +CO2 为氧化剂 ,H2 +CO2 为燃料气时 ,在不同气体利用率下电池组热平衡点的电流密度均大于 10 0mA/cm2 .提高电池组的输出功率 ,热电效率将下降 ;提高反应气压 ,热电效率相应提高     

基于纳米有机液体的高性能温差电池

传统液体温差电池较低的热电转换性能一直无法得到有效改善,亟需寻找新的热电转换机制来提升热电转换效率。本文采用分子动力学（MD）方法,数值模拟研究了不同温度下以不同配比的甘油-水为溶剂的氯化钠溶液在碳纳米管（CNT）内离子、分子分布情况。结果表明：离子、分子的分布受温度影响较大,近壁面净电荷、电势分布随温度升高出现明显的分层。根据模拟结果提出以CNT为电极材料,甘油氯化钠溶液或甘油水氯化钠溶液为电解质溶液组成温差电池。其热电转换性能远优于大多数温差电池,同时温度适用范围也显著增加。以多孔碳为电极材料,甘油氯化钠溶液为电解质溶液组成的热电转换装置实验验证了可行性。     

工业尺寸固体氧化物燃料电池高效及阳极安全运行条件研究

固体氧化物燃料电池(Solid Oxide Fuel Cell, SOFC)是一种清洁高效的能源转化装置, 如何提高SOFC的发电效率, 并保证阳极不发生局部氧化, 是工业界与学术界的焦点问题之一. 建立了工业尺寸SOFC的效率测试与评价方法, 通过对比多组高燃料利用率下的电池效率测试结果, 发现在相同燃料利用率下, 电压会随电流的增大而下降. 因此, 较低的电流有利于达到更高的效率, 较大的电流则有利于输出更高的功率. 此外, 研究了高燃料利用率下放电时电压波动与阳极局部氧化的关联, 通过分析阳极Ni的临界氧化条件, 提出了避免发生阳极局部氧化的电池安全运行条件: 电池的输出电压应高于Ni的临界氧化电动势. 基于所采用的电池和测试参数, 发现在各个电流及温度下, SOFC发电效率大于50%时, 对应的燃料利用率一般在77%~90%这一区间内, 当燃料利用率为87.10%时, 电池具有最大的发电效率. 尽管对于不同材料、结构和制备工艺的SOFC, 其最高效率所对应的工况会有所差异, 但所提出的效率测试及评价方法和阳极安全运行的判断条件具有一定的普适性, 可以根据实际需求中高功率、高效率及长期稳定运行的重要程度, 确定相应的高效及阳极安全运行条件.     

气流床煤气化炉内流动、混合与反应过程的研究进展

气流床气化过程涉及高温高压下湍流多相流动与复杂化学反应过程的相互作用,涵盖喷嘴雾化与弥散、复杂多相射流流动、炉内湍流混合、复杂气化反应、火焰结构及温度分布等诸多方面,是世界各国研究的热点.对近年来世界各国在气流床气化过程研究上取得的进展进行了综述,包括喷嘴雾化与颗粒弥散机理与雾化过程的影响因素、撞击流驻点偏移规律和撞击面振荡规律、撞击火焰结构与炉内三维温度场、典型煤种气化反应特性与石油焦气化特性以及气流床气化过程模拟.对气流床气化过程未来的研究重点进行了展望.     

温度对空间用氢镍电池电化学性能的影响

以60 Ah氢镍电池为研究对象,研究了温度对电池电性能的影响. 结果表明,电池的放电容量、过充电率随着温度均呈先升后降趋势,最高放电容量可达63.68 Ah（-5 ^oC）,电池的适合涓流值及3天自放电率随着温度的升高呈增加趋势,电池的放电容量、过充电率、适合涓流值和自放电率与环境温度之间有近似的代数公式变化关系. -10 ^oC、80%放电深度（DOD）条件下循环3000次后,电池电性能无明显衰降;25 ^oC下循环550次,放电电压跌至0.8 V,电池失效. 结合相关参考文献结果及EIS试验分析可知,25 ^oC下电池循环性能迅速失效主要是由于高温下镍电极更易析氧和发生极板腐蚀,以及高温下镍极板更易粉化所致.     

千瓦级熔融碳酸盐燃料电池堆

1.5kW级熔融碳酸盐燃料电池（molten carbonate fuel cell,MCFC）堆由15个电极面积为250mm×400mm的单电池组成.系统采用内部分配方式供给气体,通过设在电池堆上、下部和四个侧面的电炉丝进行加热.在常压和650℃条件下,分别以氢气和空气作燃料和氧化剂,经过4次热循环,电池堆的开路电压依然保持在16.33V,在运行144h后,电池堆在150mAcm^-2放电时,其峰值输出功率为1.48kW,在工作电压10.5V（平均每个单电池的工作电压为0.7V）条件下输出功率基本不变,达到825W.     

钙钛矿光伏电池封装材料与工艺研究进展

钙钛矿太阳能电池作为第3代新概念太阳能电池,具有高光电转换效率、低成本和可柔性加工等优点,近年来发展迅速,其光电转换效率从一开始的3.8%增长到近期的25.5%,逐渐比肩硅电池,已接近商业化应用水平。目前,实现钙钛矿太阳能电池产业应用的关键环节在于电池封装,它不仅可以解决钙钛矿光伏器件稳定性问题,还可以实现电池安全、环保和延长使用寿命等要求。结合近十几年来钙钛矿光伏电池封装材料和封装工艺两方面的发展现状,文中介绍了钙钛矿电池封装领域取得的成果和存在的不足,讨论了目前现有封装技术的优缺点,以及它们适用的不同器件类型。着重在不同温度湿度条件下,比较了不同封装材料性能、封装工艺条件对钙钛矿电池效率及稳定性的影响,归纳出影响钙钛矿电池薄膜封装效果的3个关键因素： 聚合物的弹性模量、水蒸气透过率、加工温度。比较了不同聚合物薄膜封装材料适宜的加工温度、优缺点及加工成本。可以看出,随着钙钛矿光伏电池工业化需求的强烈增长和人们对其封装材料研究的不断深入,研究适合大面积生产和光伏建筑一体化的新型功能聚合物封装材料将是必然趋势。     

TAG高温氧化腐蚀分析仪原理及应用

介绍了TAG高温氧化腐蚀分析仪的结构特点、工作原理及具体应用. TAG高温氧化腐蚀分析仪能够在可控气氛(干燥、潮湿和腐蚀)和可控温度的条件下实现原位测试. 双炉体设计最大程度上减小了浮力效应的干扰,并且悬挂样品设计全面积接触气氛,精确测量质量微弱变化. TAG高温氧化腐蚀分析仪可用于研究无机和有机材料等的高温分解问题,也可用于研究金属和陶瓷等材料在单一或多种气氛下的氧化腐蚀机理.     

微生物燃料电池影响因素及作用机理探讨

以生活污水为初始接种体, 以醋酸钠水溶液为原料, 构建了一个无媒介体、无膜的单室微生物燃料电池, 考察了溶液的浓度、外电阻、温度和氧气的加入等因素对电池性能的影响, 监测了电池外电压和两极电极电势的变化过程, 分析了微生物燃料电池的运行机理. 研究结果表明: (1) 阳极吸附的微生物的活性是影响电池输出电压(输出功率)的关键因素. 营养液初始浓度越高, 微生物活性越高, 输出最大电压越高, 输出电压与浓度之间的关系符合MONOD方程; 溶液中溶氧的存在使微生物活性明显降低, 但溶氧浓度降低到一定程度后, 活性逐步恢复; 随着电池温度的升高, 微生物活性快速上升, 但温度突变到50 ℃后, 微生物活性明显降低; (2) 电池换水后, 由微生物活性所决定的阳极电势迅速达到平衡, 而阴极电势需要较长的时间才能达到极大值; (3) 随电流密度的变化, 两极电极电势相应发生变化, 其变化趋势符合原电池的基本规律; (4) 随外电阻的变化, 电池输出功率出现极大值, 即当外电阻为200 Ω时, 电池输出功率达到346 mW/m2.     

多孔泡沫铜和硫脲协同作用构筑无枝晶锂负极

锂金属作为下一代储能电池的理想负极材料一直受到极大的关注,然而锂枝晶的不可控生长和负极副反应带来的低库伦效率问题严重限制了锂金属电池的发展。这里,我们提出了一种多孔泡沫铜和硫脲协同作用的策略,利用硫脲分子的超填充作用实现锂金属在多孔泡沫铜表面的均匀沉积。在电解液中添加0.02 mol·L^-1硫脲作为电解质添加剂,采用多孔泡沫铜的Li||Cu半电池在循环300圈以后,库伦效率仍保持在98%以上。此外,在5C的高倍率条件下,Li||Li FePO4全电池循环300圈以后仍有94%的容量保持率。本工作为锂金属负极保护提供了一种新的策略并且该策略也可以扩展到其他金属负极保护中,非常有利于下一代高能量密度储能电池的开发。     

Modelling of a tubular solid oxide fuel cell with different designs of indirect internal reformer

The cell performance and temperature gradient of a tubular solid oxide fuel cell with indirect internal reformer(IIR-SOFC) fuelled by natural gas, containing a typical catalytic packed-bed reformer, a catalytic coated wall reformer, a catalytic annular reformer, and a novel catalytic annular-coated wall reformer were investigated with an aim to determine the most efficient internal reformer system. Among the four reformer designs, IIR-SOFC containing an annular-coated wall reformer exhibited the highest performance in terms of cell power density(0.67 W cm-2)and electrical efficiency(68%) with an acceptable temperature gradient and a moderate pressure drop across the reformer(3.53×10-5kPa).IIR-SOFC with an annular-coated wall reformer was then studied over a range of operating conditions: inlet fuel temperature, operating pressure, steam to carbon(S : C) ratio, gas flow pattern(co-flow and counter-flow pattern), and natural gas compositions. The simulation results showed that the temperature gradient across the reformer could not be decreased using a lower fuel inlet temperature(1223 K–1173 K)and both the power density and electrical efficiency of the cell also decreased by lowering fuel inlet temperature. Operating in higher pressure mode(1-10 bar) improved the temperature gradient and cell performance. Increasing the S : C ratio from 2 : 1 to 4 : 1 could decrease the temperature drop across the reformer but also decrease the cell performance. The average temperature gradient was higher and smoother in IIR-SOFC under a co-flow pattern than that under a counter-flow pattern, leading to lower overpotential and higher cell performance. Natural gas compositions significantly affected the cell performance and temperature gradient. Natural gas containing lower methane content provided smoother temperature gradient in the system but showed lower power density and electrical efficiency.     

基于电-化-热耦合理论对称双阴极固体氧化物燃料电池堆的电流与温度场数值模拟

本文基于电-化-热多场耦合理论,通过有限元方法建立了一个基于对称双阴极结构SOFC电堆单元的三维数值模型,研究了其电堆内部的电流密度分布和温度分布. 研究结果表明,气体流动方式以及集流方式影响了电解质上电流密度和温度分布：在气体进、出气口处有较大的电流密度分布;在气体共流模式下,电解质层温度分布却较均匀;在双阴极结构电池阴极侧的单一集流模式下,集流侧的电解质的平均电流密度高于另一侧.     

Preparation of Ni–YSZ thin and thick films on metallic interconnects as cell supports. Applications as anode for SOFC

In this work, we propose the preparation of a duplex anodic layer composed of both a thin (100 nm) and a thick film (10 μm) with Ni–YSZ material. The support of this anode is a metallic substrate, which is the interconnect of the SOFC unit cell. The metallic support limits the temperature of thermal treatment at 800 °C to keep a good interconnect mechanical behaviour and to reduce corrosion. We have chosen to elaborate anodic coatings by sol–gel route coupled with dip-coating process, which are low cost techniques and allow working with moderate temperatures. Thin films are obtained by dipping interconnect substrate into a sol, and thick films into an optimized slurry. After thermal treatment at only 800 °C, anodic coatings are adherent and homogeneous. Thin films have compact microstructures that confer ceramic protective barrier on metal surface. Further coatings of 10 μm thick are porous and constitute the active anodic material.     

LaNi0.6Fe0.4O3 as a cathode contact material for solid oxide fuel cells

In solid oxide fuel cells (SOFCs) the interconnects electrically link air and fuel electrodes on either side to produce a practical electrical power output. The long-term stability of intermediate temperature (650–800 °C) SOFC operation strongly depends on the composition of the ferritic steel interconnection material and the steel/ceramic interface. During high-temperature operation the Cr-containing ferritic steel forms an oxide scale at its surface, thereby causing high ohmic electrical contact resistance when connected to the surface of an electronically conducting ceramic cathode material. In the long run, the vaporization of Cr species from these oxide scales also affects the cathode activity, eventually leading to cell deterioration. One way of overcoming the problem is to incorporate another electronically conducting ceramic compliant layer, commonly known as the contact layer, between the cathode and metallic interconnect. In this contribution, LaNi_0.6Fe_0.4O₃ was tested as a cathode contact material. Its performance at 800 °C in the form of a ~50 μm thick film applied on two ferritic steel compositions was examined. After 600 h of testing, contact resistances of 60 and 160 mΩ cm² were obtained. The different values are explained by the variation in steel composition.     

A microfluidic fuel cell with flow-through porous electrodes

A microfluidic fuel cell architecture incorporating flow-through porous electrodes is demonstrated. The design is based on cross-flow of aqueous vanadium redox species through the electrodes into an orthogonally arranged co-laminar exit channel, where the waste solutions provide ionic charge transfer in a membraneless configuration. This flow-through architecture enables improved utilization of the three-dimensional active area inside the porous electrodes and provides enhanced rates of convective/diffusive transport without increasing the parasitic loss required to drive the flow. Prototype fuel cells are fabricated by rapid prototyping with total material cost estimated at 2 USD/unit. Improved performance as compared to previous microfluidic fuel cells is demonstrated, including power densities at room temperature up to 131 mW cm-2. In addition, high overall energy conversion efficiency is obtained through a combination of relatively high levels of fuel utilization and cell voltage. When operated at 1 microL min-1 flow rate, the fuel cell produced 20 mW cm-2 at 0.8 V combined with an active fuel utilization of 94%. Finally, we demonstrate in situ fuel and oxidant regeneration by running the flow-through architecture fuel cell in reverse.     

Spatially resolved characterization of PEFCs using simultaneously neutron radiography and locally resolved impedance spectroscopy

A method for performing neutron radiography and locally resolved impedance spectroscopy simultaneously in situ in an operating polymer electrolyte fuel cell (PEFC) is presented. The new method provides concurrently spatially resolved information about the local cell performance, the locally limiting processes, and the liquid water distribution. Information about the impact of water on cell performance and limiting processes can be gained in situ on a local scale in an operating PEFC. The method was applied to a PEFC operated on pure H₂/O₂ in co-flow mode under low humidity operating conditions. The results show that in co-flow mode strong flooding and severe drying can occur at the very same time in different sections of a PEFC.     

Insights into the distribution of water in a self-humidifying H2/O2 proton-exchange membrane fuel cell using 1H NMR microscopy

Proton ((1)H) NMR microscopy is used to investigate in-situ the distribution of water throughout a self-humidifying proton-exchange membrane fuel cell, PEMFC, operating at ambient temperature and pressure on dry H(2)(g) and O(2)(g). The results provide the first experimental images of the in-plane distribution of water within the PEM of a membrane electrode assembly in an operating fuel cell. The effect of gas flow configuration on the distribution of water in the PEM and cathode flow field is investigated, revealing that the counter-flow configurations yield a more uniform distribution of water throughout the PEM. The maximum power output from the PEMFC, while operating under conditions of constant external load, occurs when H(2)O(l) is first visible in the (1)H NMR image of the cathode flow field, and subsequently declines as this H(2)O(l) continues to accumulate. The (1)H NMR microscopy experiments are in qualitative agreement with predictions from several theoretical modeling studies (e.g., Pasaogullari, U.; Wang, C. Y. J. Electrochem. Soc. 2005, 152, A380-A390), suggesting that combined theoretical and experimental approaches will constitute a powerful tool for PEMFC design, diagnosis, and optimization.     

Improvement of the performance of the ultrafiltration of bentonite suspensions using a swirling decaying annular flow: comparison with tangential plane and axial annular flows

The limiting flux induces a performance limitation of ultrafiltration systems, the understanding of this phenomenon and the ability to predict the limiting flux are essential for improving the design and operation of ultrafiltration processes. A new cell design, an annular cell fitted with a tangential inlet, which induces a swirling decaying flow, is tested. Performances of this ultrafiltration unit configuration are compared with two other more classical geometries: a simple plane unit and an annular cell involving mainly axial flow. The cross-flow ultrafiltration of dilute suspensions of bentonite is studied under specific operating conditions in the three different configurations of filtration cells. The improvement of the permeation flux in the swirling cell, compared with that measured in the two other configurations, can reach 70% for a wall velocity gradient of 800 s⁻¹. This enhancement is highly linked to the removal of particles deposited at the membrane surface owing to the three-dimensional fluid flow involved in this particular cell. The bentonite deposit is compressible and characteristics of particles accumulation at the membrane surface are investigated.     

Characteristic simulation with various anode support thicknesses of membrane electrode assembly in SOFC

This study focuses on the research of solid oxide fuel cell (SOFC) and proposes reasonably practical designs, analyses, and numerical analyses with coupling software in physics, COMSOL Multiphysics, as the analysis tool to discuss the effects on the SOFC performance. This research applies the design of electrode support (anode support) to substitute the original electrolyte support, Yttria-stabilized zirconia, so that the electrolyte membrane could form a membrane to reduce ohmic resistance and increase power density. This study further discusses the effects of various flow fields (counterflow and co-flow) on internal mass transfer and SOFC performance. The findings show that the cell performance of SOFC with co-flow is better than counterpart with counterflow under anode support thickness 1,000 μm. Regarding the analyses of porosity effect with the porosity 0.7 and tortuosity 4.5, the power density reaches the maximum that could enhance the cell performance.     

复合阳极共烧制备致密La0.7Ca0.3Cr0.97O3-δ连接体薄膜的研究

固体氧化物燃料电池(SOFC)陶瓷连接材料的低成本薄膜化制备是现在公认的技术难题。为了改善传统NiO/YSZ阳极与LaCrO3基连接材料的共烧匹配性能,将化学性质稳定的Y0.7Ca0.3Cr0.9Zn0.1O3-δ(YCCZ)连接材料创造性地引入到NiO/YSZ阳极中,制备NiO/YSZ/YCCZ(6∶4∶2,m/m/m)三相复合阳极,并进行烧结特性、微观结构、电导率、热膨胀系数等系列性能的对比测试,结果表明NiO/YSZ/YCCZ新型复合阳极具有优良的综合性能。以NiO/YSZ/YCCZ为支撑体,采用浆料浸渍法制备湿膜,1 400℃空气条件下共烧,成功制备致密La0.7Ca0.3Cr0.97O3-δ连接体薄膜。