Papers by Author: Guang Yao Meng

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Authors: Hai Bin Li, Chang Rong Xia, Xiao Hong Fan, Xi He, Xiaoliang Wei, Guang Yao Meng
Abstract: In the development of intermediate temperature solid oxide fuel cell (IT-SOFC), the anode supported thin electrolyte with higher conductivity than YSZ is an essential approach in recent years. In this work, we report our route that Ce0.8Sm0.2O1.9 (SDC) as electrolyte and porous NiO-SDC as anode substrate are prepared by a bi-layer tape casting and co-sintering process. The major effort was to adjust and control the shrinkage of the two material layers. It was found that only the specimens with less than 0.1% mismatching of the sintering shrinkage between two layers can result in the flat and crack free samples. In addition, high activity powders were the essential to obtain dense SDC electrolyte. Fuel cells with Sm0.5Sr0.5CoO3 as cathode were tested. The open circuit voltage (OCV) and the power density of the cells confirmed the full densification of the SDC electrolyte on the anode support.
Authors: Yan Hong Yin, Chang Rong Xia, Wei Zhu, Guo Yong, Guang Yao Meng
Abstract: NiO-SDC(Ce0.8Sm0.2O1.9) cermet anodes for solid oxide fuel cells (SOFCs) were fabricated by sintering NiO-SDC composite particles derived from gel-casting. The influence of Ni content and sintering temperature on the electrode polarization using humidified CH4 as fuel was investigated in order to optimize the fabrication conditions. The lowest anodic polarization was obtained for an anode sintered at 1350 oC and consisting of equal volume of Ni and SDC. The anodic polarization at 600 oC was about 37mV at a current density of 300mA/cm2. Maximum power density of 352 mW/cm2 was achieved at 600oC for a single cell based on the optimized anode, inferring high catalytic activity of the gel-cast Ni-SDC anode. This high performance seems to be attributed to the microstructure in which Ni and SDC are uniformly distributed.
Authors: Ji Gui Cheng, Hai Bin Li, Xing Qin Liu, Guang Yao Meng
Authors: Xing Yan Xu, Chang Rong Xia, Shou Guo Huang, Guang Yao Meng
Abstract: Composites consisting of silver and yttria-stabilized bismuth oxide (YSB) were fabricated and investigated as cathodes for intermediate-temperature solid oxide fuel cells (SOFCs) with thin electrolyte films of yttria-stabilized zirconia (YSZ). The films were deposited using spin coating with YSZ suspension. Comparison of YSB-Ag and conventional La0.8Sr0.2MnO3 (LSM) based cathodes showed that the YSB-Ag composite has better electrochemical performance; Interfacial polarization resistance of YSB-Ag cathode is 0.13 Ωcm2 at 750oC. Power density of the single cell with YSB-Ag cathode was about 535 mW/cm2 at 750oC, while that with LSM-Sm0.2Ce0.8O1.9 cathode was only 329 mW/cm2.
Authors: Xue Bin Zhang, Jun Xu, Xiang Jun Ren, Xing Qin Liu, Guang Yao Meng
Authors: Qi Bing Chang, Jian Er Zhou, Yong Qing Wang, Guang Yao Meng
Abstract: Porous ZrO2 single crystals were prepared through a sol-gel-hydrothermal method and characterized by XRD, HR-TEM, SEM and FT-IR. The results show that the dried sol gel was converted into monoclinic zirconia crystals after calcined above 550 °C. The zirconia single crystal has a porous structure with the crystal sizes of 20-70 nm. The origin of the pores was the gaseous hydrolysates of the superstoichiometric urotropine. The gel structure and the hydrothermal treatment are the required conditions resulting in the pores in crystals. After sintered at 1400 °C, the disc of the obtained ZrO2 crystals was dense. However, Y2O3 should be added to avoid fracture due to phase change if the disc was used as heat insulating layer.
Authors: Hong Hai Zhong, Ji Gui Cheng, Xing Qin Liu, Guang Yao Meng
Abstract: La1-xCaxCrO3 (0.1≤ x ≤ 0.4) is usually used as interconnect material for solid oxide fuel cells (SOFCs). In this paper, composite material, the two-phase mixtures of face-centered cubic fluorite structure CayCe1-yO2-y (0 ≤ y≤ 0.2) and orthorhombic perovskite structure [Sm(Eu,Gd)]1-zCazCrO3 (0 < z < 0.3), was prepared by an auto-ignition process in which mixed rare earth oxides (Sm2O3, Gd2O3, Eu2O3 and CeO2) are substituted for La2O3 in La1-xCaxCrO3. The direct current (DC) four-probe technique measurement indicated that the electrical conductivities of specimens increased along with the increase of Ca2+ content (x), especially when x=0.3 and 0.4. The material (x=0.4, about 94% relative density) showed excellent electrical conductivities of 48 Scm-1 in air and 13 Scm-1 in H2 (purity 99.999%) at 700°C respectively, which is about 3 times as high as that of La0.7Ca0.3CrO3.
Authors: Ji Gui Cheng, Q.X. Fu, Xing Qin Liu, Ding Kung Peng, Guang Yao Meng
Authors: Wei Tao Bao, Jian Feng Gao, Guang Yao Meng
Abstract: A single cell with a two-layer electrolyte consisting of an yttria stabilized zirconia (YSZ, Y2O3 8 mol%) layer and an Sm-doped ceria (SDC, Sm2O3 20mol%) interlayer has been fabricated on porous YSZ-NiO anode support. The layer of YSZ electrolyte was prepared by modified electrostatic powder coating method and the SDC interlayer by screen-printed method on the green YSZ layer. After co-firing at 1400°C for 5 h, the two-layer film with a dense YSZ film of about 15μm and porous SDC film of about 25μm was fabricated. The performances of as-fabricated single cell using La0.8Sr0.2FeO3 as cathode were tested using H2-3% H2O as fuel and air as oxidant at 800°C. Results indicated that the peak power density of a single cell with SDC interlayer reaches 469 mW/cm2 at 800°C, obviously higher than that of without SDC interlayer, which is about 300 mW/cm2 at 800°C.
Authors: Hai Yan Song, Hong Fu Jiang, Xing Qin Liu, Yin Zhu Jiang, Guang Yao Meng
Abstract: Nanocrystalline tungsten oxide doped titanium dioxide (WOx-TiO2) powders were prepared by TiCl4 hydrolysis and characterized by XRD, XPS, UV–Vis absorption spectra and TEM. Results showed that WOx not only hindered the growth of TiO2 particles but also greatly increased the transformation temperature (>800 oC) from anatase to rutile during sintering; the dominant fraction of tungsten oxides was non-stoichiometric tungsten oxide (WxOy) with Wn+ (4
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