H2S固体氧化物燃料电池的制备及其性能

采用尿素燃烧法制备La0.6Sr0.4Co0.2Fe0.8O3-δ(记作LSCF,下同)钙钛矿型阴极催化剂前体粉末,经800℃锻烧后具有典型的钙钛矿结构。在400～950℃温度范围内,催化剂具有较高的电导率,满足固体氧化物燃料电池阴极的要求。研究了以H2S为燃料气时,单体固体氧化物燃料电池(CoS-Mo2S)/BaCe0.9-xZrxY0.1O3/LSCF在不同温度下的电化学性能以及脱硫性能。结果表明:电池的最大电流密度、最大功率密度以及对H2S的脱除率均随温度的升高而增大;在反应温度为850℃,燃气流量为50 mL/min的条件下,电池的最大电流密度和最大功率密度分别为39.52 mA/cm2,6.38 mW/cm2;900℃时,H2S的脱除率达72%。     

高效双室微生物燃料电池的运行特性

微生物燃料电池(MFC)在产生电流的同时还能处理糖蜜废水和电镀废水,并能从电镀废水中回收金属单质。本实验确定了电镀废水阴极液对双室微生物燃料电池产电性能的影响,阴极液分别采用银离子、铜离子和锌离子溶液作为MFC的阴极液,其初始浓度均配成1000mg/L。结果表明,锌离子作为阴极时MFC的产能效果最不理想,功率密度仅为1.9×10-6mW/m2。阴极为铜离子溶液时,可以获得相对大一些的功率密度(13.9mW/m2)。产能效果最好的是银离子阴极MFC,在电流密度为82.7mA/m2其获得最大功率密度为23.1mW/m2,COD去除率为71%,且其重金属去除率最大(72%),远远高于锌离子和铜离子。研究表明,重金属离子可以作为微生物燃料电池的阴极电子受体,MFC可以将有机废水中的化学能直接转化为电能,同时将重金属还原,具有显著的环境效益和经济效益。     

温度对微生物燃料电池电化学性能的影响

分别在20℃,37℃和45℃三个温度条件下以间歇方式运行大肠杆菌生物燃料电池(MFC),研究功率密度、电极电势、电化学阻抗等电化学性质随温度的变化规律.结果表明:温度从20℃提高到37℃,最大功率密度从53.35 mW/m2 (275 mA/m2)增加到610.5 mW/m2(2775 mA/m2),增长了10.5倍;同时阳极电极电势降低;且阳极电化学阻抗由741.9 Ω降低到42.4 Ω.在一定温度范围内,升高温度不仅能提高电池功率输出,而且能增强其电化学活性.但是,太高的温度反而不利于生物燃料电池的运行.45℃时的最大功率密度只有171 mW/m2(600 mA/m2),比37℃时最大功率610.5 mW/m2(2 775 mA/m2)减少72％;同时阳极电化学阻抗由42.4 Ω增加到416.1 Ω.大肠杆菌生物燃料电池在37℃时具有最佳的电化学性能.可见,温度在生物燃料电池运行中是一个非常重要的操作参数.     

Ni-CGO阳极支撑ScSZ/CGO复合电解质电池的制备及性能

用柠檬酸溶胶-凝胶法合成了Ce0.85Gd0.15O2-δ(CGO),用共沉淀法合成了掺摩尔分数为11%Sc2O3稳定的ZrO2(scandium oxide-stabilized zirconia,ScSZ)电解质材料.通过X射线衍射和透射电镜对电解质材料的物相、形貌和成分进行表征.结果表明:CGO和ScSZ在各自的煅烧温度下均形成了单-的立方萤石结构晶态;ScSZ颗粒的粒径约为20nm.用共压法分别制备了以NiO-CGO阳极支撑的CGO单层电解质和ScSZ/CGO复合电解质的基体,并在基体上涂覆阴极制作单电池.在650～800℃范围内测试单电池的电性能.结果表明:ScSZ/CGO双层电解质电池的开路电压和最大功率密度均高于单层CGO电解质电池;在800℃电流密度和功率密度达到最大值,分别为677.5 mA/cm2和197.3 mW/cm2.说明SeSZ/CGO双层电解质有效地提高了电池的性能.     

微生物燃料电池处理含铬废水

采用双室的微生物燃料电池装置,探讨利用微生物燃料电池处理含铬废水的效率及电池性能.通过测定微生物燃料电池的电压、功率密度和电流密度,研究电池的性能,通过测定出水中Cr(Ⅵ)的浓度探讨微生物燃料电池对Cr(Ⅵ)的处理效率.结果表明,最大值出现在第21天,大约在18 mV左右;电压的最小值在0.5 mV左右,稳定值在2mV左右;装置稳定后,在电流密度等于0.526μA/cm2时,电池的电压达到最大值,为39.5 mV;当电流密度为1.328μA/cm2,功率密度达到最大值,为1.328×10-3mW/cm2;利用微生物燃料电池装置对Cr(Ⅵ)可以达到一定的处理效果,去除率约为20％.     

实心多孔支撑体全膜化微型固体氧化物燃料电池的制备及性能

提出一种实心多孔支撑体全膜化微型固体氧化物燃料电池(micro solid oxide fuel cell,μSOFC)设计模型.电池用氧化钇部分稳定的氧化锆[(ZrO2)0.97(Y2O3)0.03,partially stabilized zirconia,PSZ]多孔陶瓷作为支撑体,在其上制备NiO-YSZ阳极层,分别采用离心和浸渍两种成膜工艺制备YSZ电解质膜,以La0.8Sr0.2MnO3-YSZ复合材料为阴极,对组装好的单电池进行了电化学性能测试.在850℃和800℃时,离心沉积工艺制备的单电池最大输出功率密度分别为286 mW/cm2和254 mW/cm2,而浸渍涂布法制备单电池的最大输出功率密度则分别达到572 mW/cm2和388 mW/cm2.电化学阻抗谱显示;电极极化是影响电池性能的主要因素.     

活性炭空气阴极微生物燃料电池的放大和串并联组合研究

采用体积分别为28 mL(mL-MFC)和4.5 L(L-MFC)的单室空气阴极微生物燃料电池,考察了扩大化对活性炭空气阴极性能的影响.mL-MFC的最大功率密度为30 W/m3(1 200 mW/m2),L-MFC的最大功率密度为7.3 W/m3 (435 mW/m2),扩大化后活性炭空气阴极性能下降是致使L-MFC功率降低的主要原因.电化学阻抗(EIS)分析表明,L-MFC中阴极性能下降主要是由于工作水压增大,导致了阴极扩散电阻增大和氧气还原速率降低.通过串联或并联方式组合L-MFC,可明显提高电池的输出电压或电流;串并联组合后电池的功率密度有所下降,主要由电池连接时的接触电阻引起.     

镍-纳米二氧化钛复合镀层的制备及性能

以多孔泡沫镍为基体,通过在瓦特镀镍液中复合电沉积,得到Ni-TiO2复合镀层.研究了阴极电流密度、pH、时间、镀液中纳米TiO2质量浓度及分散剂种类对Ni-TiO2复合镀层的TiO2含量、表面形貌及光催化性能的影响.通过正交试验得到最佳工艺条件为:TiO2质量浓度10g/L,pH=4.0,阴极电流密度30 mA/cm2...     

非贵金属催化碱性硫离子-空气燃料电池

以碱性硫离子电解液作为阳极燃料构建了硫离子-氧气燃料电池体系,采用粉末活性炭材料制备了涂膏电极,将碱性硫化钠溶液作为阳极燃料,通过建立电化学三电极模型对电极在碱性硫离子溶液中的放电性能进行研究,主要考察了硫离子浓度、体系温度对开路电位以及放电平台的影响。电极在碱性硫离子溶液中具有较负的开路电位和稳定的放电平台;通过单体电池测试在0.24V电压下获得11mW/cm2的最大功率密度,此时电池的电流密度为46mA/cm2,证明碱性硫离子燃料电池在阳极不使用贵金属催化剂的情况下表现出良好的放电性能,是一种具有潜在研究价值和广泛应用前景的电化学体系。     

燃料电池与碳纤维之应用

介绍了以氢气为主要反应物的燃料电池作为替代性能源无污染和高效率的特点,燃料电池的应用领域、电池种类、工作原理和组成元件,以及逢甲大学研发之燃料电池气体扩散层技术。测试结果表明:当Load0.5V时,该自制的新型气体扩散层电流密度可达1026.4～1149.6mA/cm,而商用气体扩散层电流密度为941.6mA/cm;自制气体扩散层功率密度可达600mW/cm,而商用气体扩散层功率密度为511.2mW/cm,均高过商用气体扩散层。     

Carbon-air fuel cell without a reforming process

This paper describes a direct carbon-air fuel cell (DCFC) which uses a molten hydroxide electrolyte. In DCFCs, carbon is electrochemically directly oxidized to generate the power without a reforming process. Despite its compelling cost and performance advantages, the use of molten metal hydroxide electrolytes has been ignored by DCFC researches, primarily due to the potential lack of invariance of the molten hydroxide electrolyte caused by its reaction with carbon dioxide. This paper describes the electrochemistry of a patented medium-temperature DCFC based on molten hydroxide electrolyte, which overcomes the historical carbonate formation.To date, four successive generations of DCFC prototypes have been built and tested to demonstrate the technology, all using graphite rods as their fuel source. These cells all used a simple design in which the cell containers served as the air cathodes and successfully demonstrated delivering more than 40 A with the current density exceeding 250 mA/cm². The cathode is of non-porous structure made of an inexpensive Fe-Ti alloy, and gaseous oxygen is introduced into the cell by bubbling humid air through the electrolyte. Results obtained indicated that the cell operation was under a mixed Ohmic-mass transfer control. Anode and cathode reaction mechanisms are also discussed.     

An Intermediate-temperature H2S Fuel Cell with a Li2SO4-based Proton-conducting Membrane

A laboratory-scale intermediate-temperature H2S fuel cell with a configuration of H2S, （metal sulfide-based composite anode）/Li2SO4＋Al2O3/（NiO-based composite cathode）, air was developed and studied for production of power and for desulfurization of a fuel gas process stream. The cell was run at typical temperature （600-650℃） and ambient pressure, but its electrochemical performance may be limited by electrolyte membrane thickness. The membrane and its performance in cell have been characterized using scanning electron microscope （SEM） and electrochemical impedance spectrum （EIS） techniques. Composite anodes based on metal sulfides, Ag powder and electrolyte behaved well and stably in H2S stream, and composite cathodes based mainly on nickel oxide, Ag powder and electrolyte had superior performance to Pt catalyst. The maximum power density of up to 70mW.cm^-2 and current density of as high as 250mA.cm^-2 were obtained at 650℃. However, the long-term cell stability remains to be investigated.     

Improvement of sediment microbial fuel cell performance by application of sun light and biocathode

Three series of experiments were conducted to improve sediment microbial fuel cell (SMFC) performance. At first, dissolved oxygen level of catholyte was increased with native seaweed of the Caspian Sea. Power output was improved about 2-fold, and maximum power density of 46.14 8mW/m² was produced in the presence of seaweed as biocathode in cathode compartment. Secondly, the best depth to embed anode was then determined. Anode was embedded in 3, 6, 9 and 12 cm below the sediment/water interface. The best depth to bury the anode was finally determined in 3 cm below the sediment/water interface, maximum generated power and current density of 42.156 mW/m² and 282.92 mA/m², were respectively obtained in this depth. In addition, influence of agitated flow on power generation from SMFC was investigated.     

Fuel cell power generation from marine sediments: Investigation of cathode materials

BACKGROUND: Marine sediment microbial fuel cells (MFC) utilise oxidisable carbon compounds and other components present in sediments on ocean floors and similar environments to produce power in conjunction with, principally, oxygen reduction at the cathode in the overlying water. The aim of the work was to investigate a range of cathode materials for sediment MFC, to achieve relatively high levels of power. RESULTS: Cell potential and power density performance data are reported for sediment MFC using cathodes of: carbon sponge, cloth and paper, graphite and reticulated vitreous carbon (RVC), Co and Fe‐Co tetramethoxyphenyl porphyrin (FeCoTMPP) and platinised carbon and titanium. The anode was graphite cloth. After a period of stabilisation, open circuit voltages of 700 mV and maximum power densities of 62 mW m^?2 were obtained, using FeCoTMPP. Relatively low cost carbon cathodes gave power densities of around 30 mW m^?2. CONCLUSIONS: The study has shown that low level power can be produced from marine sediments using MFC without separators between the fuel and seawater containing dissolved oxygen. Cathode performance was an important factor determining the power output. Electrocatalyst at the cathode improved performance: FeCoTMMP gave power densities of 60 mW m^?2 which was twice that achieved with the best un‐modified carbon. Copyright © 2008 Society of Chemical Industry     

厌氧流化床无膜微生物燃料电池的床层膨胀高度与产电特性

考察了厌氧流化床床层膨胀高度对电池不同阴极位置(阴极1, 2, 3分别位于分布板上方150, 250, 350 mm)产电性能的影响. 膨胀高度低于170 mm时,电池功率随阴极位置沿轴向高度增加而减小,同一流速下,阴极1的最大电极输出功率最大,为347.1 mW/m2. 膨胀高度在170~270 mm时,同一流速下,阴极2的最大产电功率高于阴极1和阴极3,当流速为8.35 mm/s 时,达361.0 mW/m2. 膨胀高度在400 mm以下,同一流速下3处阴极的最大产电功率均降低,阴极3最大产电功率降低幅度较小,为297.5 mW/m2,电池功率随阴极位置沿轴向高度增加而增大. 该结果是流速对阳极室内传质及电子传递效率、流速对微生物膜生长双重影响的结果.     

自呼吸式MEMS微燃料电池的结构及其性能

利用MEMS技术设计并制作了有效面积为1.2cm×1.2cm的不同阳极和阴极结构,将它们组成电池并进行比较。结果表明,阳极采用点-蛇形混合流场,电池峰值功率密度为比点状流场的电池可提高10.4%;阴极采用双层镂空流场,峰值功率密度比单层镂空流场电池增加15.7%。最优结构电池在30%～50%相对湿度下性能良好,200mA恒流放电近610h,电池电压比较稳定。     

以Ni-YSZ和Sm0.5Sr0.5Fe0.8Cu0.2O3-δ为电极的微管固体氧化物燃料电池的制备及电化学性能（英文）

分别以Ni-YSZ中空纤维为阳极和Sm0.5Sr0.5Fe0.8Cu0.2O3–δ–Sm0.2Ce0.8O1.9（SSFCu-SDC）为阴极制备了微管固体氧化物燃料电池（SOFC）。利用扫描电子显微镜（SEM）、电化学工作站表征了微管单电池的显微结构与电化学性能。SEM分析表明,采用相转化法制备的Ni-YSZ中空纤维阳极呈特殊的非对称结构,主要由中间海绵状结构和内外两侧的指孔状多孔结构构成。通过真空辅助浸渍涂覆法和与阳极共烧技术在阳极支撑体上制备了致密的YSZ电解质膜和SDC过渡层。分别采用湿氢为燃料和静态环境空气为氧化剂测定了制备的微管单电池在650～750℃时的电化学性能。结果表明,该微管单电池具有高的输出性能,在750、700℃和650℃时的最大功率密度分别可达到485.9、382.7mW/cm2和260.3mW/cm2。     

DIRECT ELECTROCHEMICAL POWER GENERATION FROM CARBON IN FUEL CELLS WITH MOLTEN HYDROXIDE ELECTROLYTE

Historically, despite its compelling cost and performance advantages, the use of a molten metal hydroxide electrolyte has been ignored by direct carbon fuel cell (DCFC) researchers, primarily due to the potential for formation of carbonate salt in the cell. This article describes the electrochemistry of a patented medium-temperature DCFC based on a molten hydroxide electrolyte, which overcomes the historical carbonate formation.

An important technique discovered for significantly reducing carbonate formation in the DCFC is to ensure a high water content of the electrolyte. To date, four successive generations of DCFC prototypes have been built and tested to demonstrate the technology - all using graphite rods as their fuel source. These cells all used a simple design in which the cell containers served as the air cathodes and successfully demonstrated the ability to deliver more than 40 A with the current density exceeding 250 mA/cm². Conversion efficiency greater than 60% was achieved.     

中温固体氧化物燃料电池SmBaCo_2O_（5＋δ）–Sm_（0.2）Ce_（0.8）O_（1.9）复合阴极材料的电化学性能

采用柠檬酸–硝酸盐自蔓延燃烧法分别合成了双钙钛矿结构的SmBaCo2O5＋δ（SBCO）阴极粉体和萤石型Sm0.2Ce0.8O1.9（SDC）电解质粉体,按3：2的质量比混合上述粉体研磨后得到复合阴极。利用X射线衍射仪研究化学相容性,直流四端子法测量电导率,热膨胀仪测量热膨胀系数;构建阳极支撑型单电池（Ni-SDC｜SDC｜SBCO-SDC）并进行了性能测试,用扫描电子显微镜观察电池的断面微结构,交流阻抗谱记录界面极化。结果表明：SBCO与SDC在1 000℃无相互作用;450～800℃,复合阴极的电导率在369～234 S/cm之间;SDC的加入降低了复合阴极的热膨胀系数;单电池具有理想的微观结构,阳极｜电解质｜阴极各界面彼此接触良好,650℃时极化电阻仅为0.031.cm2;以H2为燃料气（含体积分数3%水蒸气）,空气为氧化剂,650℃时电池的开路电压为0.77 V,输出功率最大值为640 mW/cm2。预示着SBCO-SDC是中温固体氧化物燃料电池有潜力的阴极材料。