| 1. |
- Chen, Mingming, et al.
(författare)
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Ceria-carbonate composite for low temperature solid oxide fuel cell : Sintering aid and composite effect
- 2014
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 39:23, s. 12309-12316
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the effect of carbonate content on microstructure, relative density, ionic conductivity and fuel cell performance of Ce0.8Sm0.2O1.9-(Li/Na)(2)CO3 (SDC-carbonate, abbr. SCC) composites is systematically investigated. With the addition of carbonate, the nanoparticles of ceria are well preserved after heat-treatment. The relative densities of SCC pellets increase as the carbonate content increases or sintering temperature rises. Especially, the relative density of SCC2 sintered at 900 degrees C is higher than that of pure SDC sintered at 1350 degrees C. Both the AC conductivity and DC oxygen ionic conductivity are visibly improved compared with the single phase SDC electrolyte. Among the composites, SDC-20 wt% (Li/Na)(2)CO3 (SCC20) presents high dispersion, relative small particle size, and the dense microstructure. The optimized microstructure brings the best ionic conductivity and fuel cell performance. It is hoped that the results can contribute the understanding of the role of carbonate in the composite materials and highlight their prospective application.
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| 2. |
- Di, Jing, et al.
(författare)
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Samarium doped ceria-(Li/Na)(2)CO3 composite electrolyte and its electrochemical properties in low temperature solid oxide fuel cell
- 2010
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 195:15, s. 4695-4699
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Tidskriftsartikel (refereegranskat)abstract
- A composite of samarium doped ceria (SDC) and a binary carbonate eutectic (52 mol% Li2CO3/48 mol% Na2CO3) is investigated with respect to its morphology, conductivity and fuel cell performances. The morphology study shows the composition could prevent SDC particles from agglomeration. The conductivity is measured under air, argon and hydrogen, respectively. A sharp increase in conductivity occurs under all the atmospheres, which relates to the superionic phase transition in the interface phases between SDC and carbonates. Single cells with the composite electrolyte are fabricated by a uniaxial die-press method using NiO/electrolyte as anode and lithiated NiO/electrolyte as cathode. The cell shows a maximum power density of 590 mW cm(-2) at 600 degrees C, using hydrogen as the fuel and air as the oxidant. Unlike that of cells based on pure oxygen ionic conductor or pure protonic conductor, the open circuit voltage of the SDC-carbonate based fuel cell decreases with an increase in water content of either anodic or cathodic inlet gas, indicating the electrolyte is a co-ionic (H+/O2-) conductor. The results also exhibit that oxygen ionic conductivity contributes to the major part of the whole conductivity under fuel cell circumstances. (C) 2010 Elsevier B.V. All rights reserved.
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| 3. |
- Fan, Liangdong, 1985-
(författare)
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Development and characterization of functional composite materials for advanced energy conversion technologies
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The solid oxide fuel cell (SOFC) is a potential high efficient electrochemical device for vehicles, auxiliary power units and large-scale stationary power plants combined heat and power application. The main challenges of this technology for market acceptance are associated with cost and lifetime due to the high temperature (700-1000 oC) operation and complex cell structure, i.e. the conventional membrane electrode assemblies. Therefore, it has become a top R&D goal to develop SOFCs for lower temperatures, preferably below 600 oC. To address those above problems, within the framework of this thesis, two kinds of innovative approaches are adopted. One is developing functional composite materials with desirable electrical properties at the reduced temperature, which results of the research on ceria-based composite based low temperature ceramic fuel cell (LTCFC). The other one is discovering novel energy conversion technology - Single-component/ electrolyte-free fuel cell (EFFC), in which the electrolyte layer of conventional SOFC is physically removed while this device still exhibits the fuel cell function. Thus, the focus of this thesis is then put on the characterization of materials physical and electrochemical properties for those advanced energy conversion applications. The major scientific content and contribution to this challenging field are divided into four aspects except the Introduction, Experiments and Conclusions parts. They are:Continuous developments and optimizations of advanced electrolyte materials, ceria-carbonate composite, for LTCFC. An electrolysis study has been carried out on ceria-carbonate composite based LTCFC with cheap Ni-based electrodes. Both oxygen ion and proton conductance in electrolysis mode are observed. High current outputs have been achieved at the given electrolysis voltage below 600 oC. This study also provides alternative manner for high efficient hydrogen production. Compatible and high active electrode development for ceria-carbonate composite electrolyte based LTCFC. A symmetrical fuel cell configuration is intentionally employed. The electro-catalytic activities of novel symmetrical transition metal oxide composite electrode toward hydrogen oxidation reaction and oxygen reduction reaction have been experimentally investigated. In addition, the origin of high activity of transition metal oxide composite electrode is studied, which is believed to relate to the hydration effect of the composite oxide.A novel all-nanocomposite fuel cell (ANFC) concept proposal and feasibility demonstration. The ANFC is successfully constructed by Ni/Fe-SDC anode, SDC-carbonate electrolyte and lithiated NiO/ZnO cathode at an extremely low in-situ sintering temperature, 600 oC. The ANFC manifests excellent fuel cell performance (over 550 mWcm-2 at 600 oC) and a good short-term operation as well as thermo-cycling stability. All results demonstrated its feasibility and potential for energy conversion.Fundamental study results on breakthrough research Single-Component/Electrolyte-Free Fuel Cell (EFFC) based on above nanocomposite materials (ion and semi-conductive composite) research activities. This is also the key innovation point of this thesis. Compared with classic three-layer fuel cells, EFFC with an electrolyte layer shows a much simpler but more efficient way for energy conversion. The physical-electrical properties of composite, the effects of cell configuration and parameters on cell performance, materials composition and cell fabrication process optimization, micro electrochemical reaction process and possible working principle were systematically investigated and discussed. Besides, the EFFC, joining solar cell and fuel cell working principle, is suggested to provide a research platform for integrating multi-energy-related device and technology application, such as fuel cell, electrolysis, solar cell and micro-reactor etc.This thesis provides a new methodology for materials and system innovation for the fuel cell community, which is expected to accelerate the wide implementation of this high efficient and green fuel cell technology and open new horizons for other related research fields.
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| 4. |
- Fan, Liangdong, 1985-, et al.
(författare)
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Effective hydrogen production by high temperature electrolysis with ceria-carbonate composite
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The high temperature electrolysis potentially offers an effective approach for large-scale and high purity hydrogen production. Besides, the research on the hybrid oxygen ion/proton conductive behavior is a hot field in the ceria-based composite field. In this present study, single cell assembled by SDC-carbonate electrolyte and Ni-based electrode was fabricated and operated in ceramic electrolysis cells (CECs) model. The effect of the relative humidity and temperature on the electrochemical performance was investigated by electrochemical impedance spectra (EIS) and polarization curves. Under an applied electrolysis voltage of 1.6 V, the maximum consumed current density is 1.2 Acm-2 in oxygen ionic conduction mode. The electrochemical performance in proton conduction mode is comparable to the oxygen ion conduction mode. The results here again demonstrate the hybrid ionic conduction of ceria-carbonate composite, and provide a promising materials system for high efficient hydrogen production.
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| 5. |
- Fan, Liangdong, et al.
(författare)
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Electrochemical study of lithiated transition metal oxide composite as symmetrical electrode for low temperature ceramic fuel cells
- 2013
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 38:26, s. 11398-11405
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Tidskriftsartikel (refereegranskat)abstract
- In this work, Lithiated NiCuZnOx (LNCZO) composite is synthesized and evaluated as a potential symmetrical electrode for ceria-carbonate composite electrolyte based low temperature ceramic fuel cells. Its crystal structures, the hydrogen oxidation/oxygen reduction electrochemical activities and fuel cell performances are systematically examined on the symmetrical cell configuration. Nano crystallite particles in the form of composite are observed for these oxides. The LNCZO shows relatively high catalytic activities for hydrogen oxidation and oxygen reduction reaction according to the electrochemical impedance spectroscopy measurements. A remarkable low oxygen reduction activation energy of 42 kJ mol(-1) is obtained on the LNCZO/ceria-carbonate composite, demonstrating excellent electro-catalytic activity. Especially, the catalytic activity can be further improved in the presence of water in the cathode chamber. The results show that the lithiated transition metal oxide composite is a promising symmetrical electrode for ceria-carbonate electrolyte and composite approach might a probable solution to develop super-performance electrodes for reduced temperature ceramic fuel cells.
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| 6. |
- Fan, Liangdong, et al.
(författare)
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Electrolysis study of ceria-carbonate composite for effective H2 production
- 2013
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Ingår i: EFC 2013 - Proceedings of the 5th European Fuel Cell Piero Lunghi Conference. - 9788882862978 ; , s. 79-80
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Konferensbidrag (refereegranskat)abstract
- The hybrid ionic conduction of ceria-carbonate composite is an interesting field that has attracted plenty attention in the past decade. However, it has not reached universal agreement among the researcher. Novel characterization method is still needed to reveal this complex system and benefit the future advanced materials design and development. In this work, the electrolysis operation is employed to investigate the possible ionic conduction behavior of ceria-carbonate. The other goal is to optimize the processing technology to maximum the kinetics rate for efficient hydrogen production. An impressive current density of 1.2 A cm-2 has been achieved at 600 °C under voltage of 1.6 V at the absolute humidity of 3% and oxygen ionic operational mode.
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| 7. |
- Fan, Liangdong, 1985-, et al.
(författare)
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High performance transition metal oxide composite cathode for low temperature solid oxide fuel cells
- 2012
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 203:1, s. 65-71
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Tidskriftsartikel (refereegranskat)abstract
- Low temperature solid oxide fuel cells (SOFCs) with metal oxide composite cathode on the ceria–carbonate composite electrolyte have shown promising performance. However, the role of individual elements or compound is seldom investigated. We report here the effect of the ZnO on the physico-chemical and electrochemical properties of lithiated NiO cathode. The materials and single cells are characterized by X-ray diffraction, scanning electron microscopy, DC polarization electrical conductivity, electrochemical impedance spectroscopy and fuel cell performance. The ZnO modified lithiated NiO composite materials exhibit smaller particle size and lower electrical conductivity than lithiated NiO. However, improved electro-catalytic oxygen reduction activity and power output are achieved after the ZnO modification. A maximum power density of 808 mW cm−2 and the corresponding interfacial polarization resistance of 0.22 Ω cm2 are obtained at 550 °C using ZnO modified cathode and 300 μm thick composite electrolyte. The single cell keeps reasonable stability over 300 min at 500 °C. Thus, ZnO modified lithiated NiO is a promising cathode candidate for low temperature SOFCs.
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| 8. |
- Fan, Liangdong, et al.
(författare)
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Low temperature ceramic fuel cells using all nano-composite materials
- 2011
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Ingår i: EFC 2011 - Proceedings of the 4th European Fuel Cell Piero Lunghi Conference and Exhibition. - 9788882862541 ; , s. 175-176
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Konferensbidrag (refereegranskat)abstract
- Nano-structural components have attracted increasing attention in intermediate/low temperature ceramic fuel cell. We reported here a ceramic fuel cell with a configuration of (Ni/Fe)-NSDC/NSDC/LiNiZnO-NSDC by all nano-composite materials and operated at low temperature range of 500-600°C. The prepared nanocomposite materials are characterized by X-ray diffraction (XRD), Emission scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Electrochemical performances were studied by current -Voltage, power density characteristics and Ac impedance spectroscopy. The short term stability of fuel cell was also investigated in 100 min. The high fuel cell performance and reasonable stability demonstrated that the all nanocomposite fuel cell concept is feasible and may have great potential in future study.
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| 9. |
- Fan, Liangdong, et al.
(författare)
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Low temperature ceramic fuel cells using all nano composite materials
- 2012
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Ingår i: Nano Energy. - : Elsevier BV. - 2211-2855. ; 1:4, s. 631-639
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Tidskriftsartikel (refereegranskat)abstract
- The shift to low operational temperature of solid oxide or ceramic fuel cells has induced many new concepts and novel technologies. In the present study, fuel cell assembled by all nano composite materials - NiO/Fe 2O 3-SDC anode, SDC-carbonate electrolyte and lithiated NiO/ZnO cathode - is investigated. A range of techniques, i.e., X-ray diffraction (XRD), Scanning electron microscopy (SEM) and electrochemical impedance spectroscopy as well as polarization measurements are employed to characterize the crystalline structures, morphologies and electrochemical properties of the synthesized nanocomposite materials and cells. Performance comparison is made between single cells with and without a pre-sintering process. Finally, single cell short term stability and thermo cycle behaviors are also examined. Combined the facile fabrication process, relative high performance and reasonable stability, the current all nanocomposite system may be a promising functional system for low temperature ceramic fuel cells.
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| 10. |
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