低温固体氧化物燃料电池

固体氧化物燃料电池作为新型的能源转换装置,具有高效、清洁、稳定性高、灵活多样等特点,有着良好的发展前景.它的中低温化对于商业应用具有十分重要的意义,现阶段的研究重点主要集中于将操作温度从传统的800-1000℃降低到600℃甚至以下.本文集中介绍了应用于600℃以下的中低温固体氧化物燃料电池,分别从低温电解质、阴极和阳...     

不同含钴阴极在YSZ薄膜电解质固体氧化物燃料电池中的性能

固体氧化物燃料电池阴极材料的阻抗对固体氧化物燃料电池的性能有较大影响.我们通过XRD、对称电池以及单电池性能测试等方法比较系统地研究了4种最为常用的含钴阴极材料直接用于钇稳定化氧化锆（YSZ）电解质薄膜与通过引入SDC夹层后用于YSZ电解质薄膜后的性能.我们发现,不同的含钴阴极材料与YSZ材料之间都不同程度地发生相反应,在应用于YSZ电解质薄膜上时,相反应大大降低了含钴阴极材料的性能,在使用了SDC夹层后,单电池的功率输出显著提高.     

单室固体氧化物燃料电池

单室固体氧化物燃料电池使矿物燃料和氧在同一气室中反应发电,具有无需密封、结构简单及抗热和机械性能强的特点,已经显示出作为便携式电源的良好发展前景,近几年来已成为燃料电池领域的一个研究热点.本文较详细地介绍了单室固体氧化物燃料电池的发展背景、特点、工作原理和影响单室固体氧化物燃料电池性能的众多因素,阐述了它的发展历程及最新进展,并对其前景进行了展望.     

单室固体氧化物燃料电池

单室固体氧化物燃料电池使矿物燃料和氧在同一气室中反应发电,具有无需密封、结构简单及抗热和机械性能强的特点,已经显示出作为便携式电源的良好发展前景,近几年来已成为燃料电池领域的一个研究热点.本文较详细地介绍了单室固体氧化物燃料电池的发展背景、特点、工作原理和影响单室固体氧化物燃料电池性能的众多因素,阐述了它的发展历程及最新进展,并对其前景进行了展望.     

乙醇在Ni-ZnO-ZrO2-YSZ阳极SOFC上的发电性能

为考察乙醇用于固体氧化物燃料电池的可行性,用柠檬酸溶胶 凝胶制备阳极催化材料Ni-ZnO-ZrO₂,利用机械混合法制备Ni-ZnO-ZrO₂-YSZ(Y₂O₃稳定的ZrO₂)阳极。用涂覆法,在YSZ电解质上,制备了Ni-ZnO-ZrO₂-YSZ/YSZ/LSM（La_0.85Sr_0.15MnO₃）与Ni-YSZ/YSZ/LSM的单体电池。在不同蒸发器操作温度、电池操作温度和乙醇蒸气流量下,以乙醇为燃料进行发电实验,对两种阳极的电池发电性能进行比较。实验结束后,用SEM检测了两种电池阳极的表面。结果表明,Ni-ZnO-ZrO₂-YSZ阳极SOFC的电池输出性能明显高于Ni-YSZ阳极,且Ni-ZnO-ZrO₂-YSZ阳极具有较好的抗积炭能力。     

单室固体氧化物燃料电池

单室固体氧化物燃料电池使矿物燃料和氧在同一气室中反应发电,具有无需密封、结构简单及抗热和机械性能强的特点,已经显示出作为便携式电源的良好发展前景,近几年来已成为燃料电池领域的一个研究热点。本文较详细地介绍了单室固体氧化物燃料电池的发展背景、特点、工作原理和影响单室固体氧化物燃料电池性能的众多因素,阐述了它的发展历程及最新进展,并对其前景进行了展望。     

以椰壳生物质炭为燃料的直接炭固体氧化物燃料电池

通过热裂解制得椰壳炭,表征了其结构和组成,并将其用于电解质为钇稳定化氧化锆（YSZ）、电极材料为银和钆掺杂氧化铈（Ag-GDC）的固体氧化物燃料电池（SOFC）的燃料,对所构成的直接炭固体氧化物燃料电池（DC-SOFC）的性能进行了测试研究。结果表明,所制得的椰壳炭颗粒粒径在微米级别,具有介孔结构,而且椰壳炭中含有K、Ca等元素,可用作Boudouard反应催化剂。当使用椰壳炭作为DC-SOFC燃料时,在800 ℃下电池最大功率密度为255 mW/cm²;负载Fe催化剂后,最大功率密度提升为274 mW/cm²。以0.5 A/cm²的恒电流放电,0.5 g负载Fe椰壳炭燃料电池能够连续工作17.6 h,燃料利用率为39%,表明椰壳炭作为DC-SOFC燃料具有优异的性能和潜力。     

Ln_2MO_4型固体氧化物燃料电池阴极材料

发展中温固体氧化物燃料电池阴极材料面临着巨大的挑战,K2NiF4结构Ln2MO4型氧化物(Ln=La,Pr,Nd,Sm;M=Ni,Cu,Fe,Co,Mn)由于具有高的离子-电子电导率,与固体电解质匹配的热膨胀系数,较好的氧扩散及表面交换性能,得到了人们的广泛关注.这预示着该类材料有希望成为一种新型固体氧化物燃料电池阴极材料.阴极材料的高温化学稳定性研究结果表明,镍酸盐Ln2NiO4(Ln=La,Pr,Nd)氧化物与固体电解质YSZ化学相容性较差,高温时易生成绝缘相Ln2Zr2O7.相比较而言,对于掺杂型Ln2-xSrxM1-yMy/O4(Ln=La,Sm,Nd;M,M/=Cu,Fe,Ni,Co)阴极材料与传统固体电解质CGO、LSMG和YSZ等具有很好的化学相容性,高温条件下二者之间不发生化学反应.与传统的钙钛矿相比,具有相同组成元素的Ln2MO4型氧化物具有更低的热膨胀系数,并且与固体电解质有很好的热匹配性.电导率数值的大小是衡量阴极材料性能的重要指标.研究结果显示,Ln2MO4氧化物在400～600℃的混合电导率数值为40～100S/cm,且镍酸盐和钴酸盐体系普遍具有较高的数值,这对阴极来说是极为有利的....     

乙醇在Ni-ZnO-ZrO_2-YSZ阳极SOFC上的发电性能

为考察乙醇用于固体氧化物燃料电池的可行性,用柠檬酸溶胶-凝胶制备阳极催化材料Ni-ZnO-ZrO2,利用机械混合法制备Ni-ZnO-ZrO2-YSZ(Y2O3稳定的ZrO2)阳极。用涂覆法,在YSZ电解质上,制备了Ni-ZnO-ZrO2-YSZ/YSZ/LSM(La0.85Sr0.15MnO3)与Ni-YSZ/YSZ/LSM的单体电池。在不同蒸发器操作温度、电池操作温度和乙醇蒸气流量下,以乙醇为燃料进行发电实验,对两种阳极的电池发电性能进行比较。实验结束后,用SEM检测了两种电池阳极的表面。结果表明,Ni-ZnO-ZrO2-YSZ阳极SOFC的电池输出性能明显高于Ni-YSZ阳极,且Ni-ZnO-ZrO2-YSZ阳极具有较好的抗积炭能力。     

YSZ电解质薄膜的制备方法

固体氧化物燃料电池(solid oxide fuel cells, SOFC)和固体氧化物电解池(solid oxide electrolytic cells, SOEC)制备的关键技术之一是在保证致密性的前提下将Y2O3稳定ZrO2(yttria-stabled zirconia, YSZ)电解质薄膜化.本文将YSZ电解质薄膜制备方法归类为陶瓷粉末法、化学法和物理法,综述了近年来这些方法的研究进展.通过对每种方法技术特点的说明和实例举证,探讨了这些方法的优、缺点和适用场合.最后,通过分析和比较,对YSZ薄膜化方法未来的发展进行了展望.     

Co-synthesis of nano-sized LSM–YSZ composites with enhanced electrochemical property

Nano-sized LSM–YSZ composite was co-synthesized by a glycine–nitrate process (GNP). Transmission electron microscopy revealed that the as-prepared LSM–YSZ particles consist of nano-sized powders with a dominant YSZ phase. Backscatter electron image shows that LSM and YSZ phases were regularly dispersed within the composite. Alternating current impedance measurement revealed that the co-synthesized LSM–YSZ electrode shows lower polarization resistance and activation energy than the physically mixed LSM–YSZ electrode. This electrochemical improvement would be attributed to the increase in three-phase boundary and good dispersion of LSM and YSZ phases within the composite. This paper is dedicated to Professor Su-Il Pyun on the occasion of his 65th birthday.     

锰酸镧和氧化钇稳定的氧化锆复合阴极的研究

用交流阻抗,强极化和电导测量等方法考察了一系列不同氧化钇稳定氧化锆(YSZ)含量的锶掺杂锰酸镧(LSM)复合阴极的电化学性能,发现随着掺入YSZ量的增大,阴极性能大幅度提高,当YSZ质量分数为40%时,电极性能最好,电化学极化电阻约为1.18Ω/cm².通过分析发现,YSZ的掺杂使电极反应过程的控制步骤发生了变化.同时发现,随着YSZ含量的增加,电极的接触电阻增大.以Pt为电流收集层和40%的YSZ+LSM的复合电极形成的二层电极可有效地消除接触电阻,进一步提高了复合电极的性能.在1223K极化电阻从1.18Ω/cm²下降到0.41Ω/cm².     

La0.8Sr0.2MnO3/YSZ电极氧电化学还原反应动力学

用线性极化、循环伏安、电位阶跃等方法详细研究了Ｌａ０．８Ｓｒ０．２ＭｎＯ３／ＹＳＺ高温电极上进行的氧化学还原反应。实验结果表明，该反应存在两条路径：低温下氧还原反应主要发生在气相－ＬＳＭ电极－ＹＳＺ电解质接触的三相界面（ＴＰＢ），速度控制步骤为氧原子在ＬＳＭ表面的浓差扩散，高温下由于氧空位在ＬＳＭ表面的形成，氧还原反应区扩展至ＬＳＭ电极表面，速度控制步骤为氧的电荷转移反应，实验同时发现：氧空位的形     

Effect of Bi0.75Y0.25O1.5 electrolyte additive in collector layer to properties of bilayer composite cathodes of solid oxide fuel cells based on La(Sr)MnO3 and La(Sr)Fe(Co)O3 compounds

The sintering features, electroconductivity, and electrochemical characteristics of bilayer electrodes with functional composite layers based on La(Sr)MnO₃ (LSM) and La(Sr)Fe(Co)O₃ with LSM collector layer and Bi(Y)O_1.5 (YDB) electrolyte additive in contact with Ce (Sm)O₂(SDC), La(Sr)Ga(Mg)O₃, and Zr(Sc)O₂ electrolytes were studied. YDB additive to the electrode collector layer was shown to produce a positive effect to the properties of the studied electrode systems. The maximum electrochemical activity and electroconductivity was observed for the electrodes with 5 wt % of YDB electrolyte additive in the collector layer. Thus, electroconductivity of electrodes is almost doubled and 100 mV cathode overvoltage current density is increased by 30% at the temperatures of 800 to 900°C and up to 10-fold at 650 to 700°C. The collector layer sintering temperature of bilayer electrodes can be reduced from 1150 to 1000°C without loss of electrochemical activity. The service life tests (about 1200 h) of composite electrodes with LSM2-SDC functional layer and 90% LSM2 + 10% YDB collector layer in contact with SDC electrolyte showed the time dependences of polarization resistance tending to saturation and described with damped exponent. Original Russian Text ? N.M. Bogdanovich, D.I. Bronin, G.K. Vdovin, I.Yu. Yaroslavtsev, B.L. Kuzin, 2009, published in Elektrokhimiya, 2009, Vol. 45, No. 4, pp. 486–494.     

La0.8Sr0.2MnO3／YSZ高温电极交流阻抗研究

用交流阻抗方法研究了Ｌａ０．８Ｓｒ０．２ＭｎＯ３电极上进行的氧化电化学还原反应。实验表明反应速度控制步骤随反应温度，氧分压及过电位发生显著变化，近平衡下反应的ｒｄｓ为氧的解离吸附过程。强阳极极化下，电解质表面产生大量电子空穴；强阴极极化下，ＬＳＭ电极表面形成大量氧空位，二者的结果均使界面电导增加，电化学反应区扩展。     

Electrical conductivities and microstructures of LSM,LSM-YSZ and LSM-YSZ/LSM cathodes fabricated on YSZ electrolyte hollow fibres by dip-coating

Lanthanum strontium manganite – La_0.80Sr_0.20MnO₃ (LSM), LSM-Yttria stabilised zirconia (LSM-YSZ) composite and LSM-YSZ/LSM double-layer cathodes were separately fabricated on Yttria stabilised zirconia (YSZ) electrolyte hollow fibres by dip coating; their electrical conductivities and microstructures were then determined by the direct current four-probe method and scanning electron microscopy (SEM), respectively. Excellent cathode-electrolyte and cathode-cathode adhesion without delamination were achieved by the dip-coating fabrication method. The apparent electrical conductivities of porous LSM, LSM-YSZ and LSM-YSZ/LSM cathodes manufactured on YSZ hollow fibre by dip-coating and sintered at various temperatures in the range 1273–1473 K for 3 h, were 1.8 × 10³–5.5 × 10³ S/m, 0.32–209 S/m and 1.3 × 10³–5.5 × 10³ S/m, respectively, at measurement temperatures of 673–1073 K. The operating temperature dependence of the apparent electrical conductivity of the LSM, LSM-YSZ and LSM-YSZ/LSM cathodes was defined by the Arrhenius equation for electrical conductivity. The activation energies for electrical conductivity were derived as 0.106–0.147 eV, 0.83–0.94 eV, and 0.104–0.146 eV for the LSM, LSM-YSZ and LSM-YSZ/LSM cathodes, respectively. The LSM-YSZ and LSM-YSZ/LSM cathodes were strongly influenced by the YSZ and LSM phases, respectively.     

(La0.8Sr0.2)0.9MnO3–Gd0.2Ce0.8O1.9 composite cathodes prepared from (Gd, Ce)(NO3) x -modified (La0.8Sr0.2)0.9MnO3 for intermediate-temperature solid oxide fuel cells

Development of high performance cathodes with low polarization resistance is critical to the success of solid oxide fuel cell (SOFC) development and commercialization. In this paper, (La_0.8Sr_0.2)_0.9MnO₃ (LSM)–Gd_0.2Ce_0.8O_1.9(GDC) composite powder (LSM ~70 wt%, GDC ~30 wt%) was prepared through modification of LSM powder by Gd_0.2Ce_0.8(NO₃) _x solution impregnation, followed by calcination. The electrode polarization resistance of the LSM–GDC cathode prepared from the composite powder was ~0.60 Ω cm² at 750 °C, which is ~13 times lower than that of pure LSM cathode (~8.19 Ω cm² at 750 °C) on YSZ electrolyte substrates. The electrode polarization resistance of the LSM–GDC composite cathode at 700 °C under 500 mA/cm² was ~0.42 Ω cm², which is close to that of pure LSM cathode at 850 °C. Gd_0.2Ce_0.8(NO₃) _x solution impregnation modification not only inhibits the growth of LSM grains during sintering but also increases the triple-phase-boundary (TPB) area through introducing ionic conducting phase (Gd,Ce)O_2-δ, leading to the significant reduction of electrode polarization resistance of LSM cathode.     

Development of novel LSM/GDC composite and electrochemical characterization of LSM/GDC based cathode-supported direct carbon fuel cells

(La_0.8Sr_0.2)_0.95MnO_3?δ (LSM)–Gd_0.1Ce_0.9O_2?δ (gadolinium-doped ceria, GDC) composite cathode material was developed and characterized in terms of chemical stability, sintering behaviour, electrical conductivity, mechanical strength and microstructures to assess its feasibility as cathode support applications in cathode-supported fuel cell configurations. The sintering inhibition effect of LSM, in the presence of GDC, was observed and clearly demonstrated. The mechanical characterization of developed composites revealed that fracture behaviour is directly affected by pore size distribution. The Weibull strength distribution showed that for bimodal pore size distribution, two different fracture rates were present. Furthermore, the contiguity of LSM and GDC grains was calculated with image analysis, and correlation of microstructural features with mechanical and electrical properties was established. Subsequently, an LSM/GDC-based cathode-supported direct carbon fuel cell (DCFC) with Ni/ScSZ (scandia-stabilised zirconia) anode was successfully fabricated via slurry coating and co-firing techniques. The microstructures of electrodes and electrolyte layers were observed to confirm the desired morphology after co-sintering, and a single cell was electrochemically characterized in solid oxide fuel cell (SOFC) and DCFC mode with ambient air as oxidant. The higher values of open-circuit voltage indicated that the electrolyte layer prepared by vacuum slurry coating is dense enough. The corresponding peak power densities at 850 °C were 450 and 225 mW cm^?2 in SOFC and DCFC mode, respectively. Electrochemical impedance spectroscopy was carried out to observe electrode polarization and ohmic resistance.     

Behavior of manganite electrodes in contact with LSGM electrolyte: the nature of low electrochemical activity

The electrochemical cells with electrodes based on La_0.8Sr_0.2MnO₃ (LSM) and supporting solid electrolytes La_0.88Sr_0.12Ga_0.82Mg_0.18O_2.85 (LSGM) and Ce_0.80Sm_0.20O_1.90 (SDC) were studied comparatively. Characteristics of LSM electrodes and composite electrodes comprising a mixture of LSM and electrolytes of different origins [LSGM, SDC, and Zr_0.82Sc_0.18O_1.91 (SSZ) in the mass ratio of 1:1] were analyzed. It was shown that: 1) the electrode polarization conductivity and the ohmic resistance of the cells with the LSM–LSGM composite electrodes on the LSGM and SDC electrolytes had very similar values, while they were largely different from all the other electrodes, 2) the electrochemical activity of the electrodes on the SDC electrolyte was much higher than on the LSGM electrolyte, and 3) the ohmic resistance of the cells with the SDC electrolyte corresponded to the electrolyte resistance, whereas, the ohmic resistance of the cells with the LSGM electrolyte was much larger than the electrolyte resistance. The obtained results are due to the interaction between the LSM and LSM-containing electrodes with the LSGM electrolyte during sintering, leading to the formation of a product with a very low conductivity.     

A Novel Electrochemical Sensor Based on Poly(1,5-diaminonaphthalene) and Poly(1,2-diaminoanthraquinone) Core-shell Composite Electrodes for Effective Voltammetric Determination of Nitrite

In this article, poly(1,2-diaminoanthraquinone) (pDAAQ) and poly(1,5-diaminonaphthalene) (pDAN) were electrochemically deposited layer by layer on a glassy carbon electrode (GCE) to generate pDAAQ/pDAN@GCE and pDAN/pDAAQ@GCE composite electrodes, respectively. The morphology and characteristics of the modified electrodes were investigated via electrochemical impedance spectroscopy)EIS), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy)SEM). The obtained results reveal the outstanding performance of the pDAN/pDAAQ@GCE electrode for electrochemical nitrite sensing where pDAAQ plays a vital role as the inner layer. Cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV) measurements revealed that the oxidation peak current of nitrite was proportional to its concentration. The best LSV results were obtained in a concentration range of 10–150 μM, with a limit of detection of 1.2 μM. Furthermore, the pDAN/pDAAQ@GCE composite electrode was used to determine nitrite ions in real water samples with good results.