| 1. |
- Basile, A., et al.
(författare)
-
European Fuel Cell 2011
- 2013
-
Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 38:1, s. 319-319
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 2. |
- Bin, Zhu, 1956
(författare)
-
Intermediate Temperature Solid Ionic Conductors and Fuel Cells
- 1995
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Novel solid proton conductors based on oxyacid salts and salt-ceramic composites and intermediate temperature fuel cells have been developed in this thesis work. The discovery of proton conduction in these materials introduces a new concept of proton conductors and starts a new research field - Intermediate Temperature Solid Proton Conductors and Fuel Cells. In these materials highly mobile protons are present in very low concentrations resulting in a high proton conductivity, 10-2 to 10-1 S/cm, between 300 and 600 °C. Most materials investigated have a face centred cubic structure or are two-phase materials. Two types of proton bond states and proton conduction mechanisms have been suggested and are discussed. The first type is a single proton jump accompanying the hydrogen bond reorientation due to a "Paddle wheel" mechanism for the sulphates and sulphate-ceramic composites and the second type is interfacial proton conduction for the nitrate-ceramic composites. The theory for the fuel cell process, protonic conduction and diffusion processes in these types of materials is discussed. Fuel cells using these materials as electrolytes have been successfully demonstrated. A typical fuel cell performance is a current density of 300 mA/cm2 at 0.75 V, which is suitable for the requirement of commercialisation.
|
|
| 3. |
|
|
| 4. |
- Fan, Liangdong, 1985-
(författare)
-
Development and characterization of functional composite materials for advanced energy conversion technologies
- 2013
-
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.
|
|
| 5. |
- Fan, Liangdong, 1985-, et al.
(författare)
-
Effective hydrogen production by high temperature electrolysis with ceria-carbonate composite
-
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.
|
|
| 6. |
|
|
| 7. |
- Liu, Yanyan, et al.
(författare)
-
A Single-Phase Mixed-Conductive Pr-Doped CeO2 Membrane for Advanced Fuel-to-Electricity Technology
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Pr-doped CeO2 has exhibited many interesting properties relying on the flexible valence of praseodymium. The tailorable doping contents of praseodymium determine the ionic or mixed electronic-ionic conductivity properties of the Pr-doped CeO2. Interestingly, the characteristic feature that praseodymium element preferably attributes on the surface of ceria particles facilitates the surface exchange kinetics for oxygen transport relying on oxygen vacancies and resulting in high ionic conduction. Hereby, we investigated a 10 mol.% Pr-doped CeO2 (Pr-CeO2) synthesized by hydrothermal method focusing on its surface conductive properties. The as-prepared Pr-CeO2 exhibited a high electrical conductivity of 0.36 S cm-1 at 600 ℃. Using this mixed conductive Pr-CeO2, we fabricated a solid oxide fuel cell (SOFC) device in a ‘sandwich’ configuration while p-type semiconductor Ni0.8Co0.15Al0.05Li-oxide was pasted on both sides of Pr-CeO2 membrane layer. This device exhibited a comparable peak power density of 776 mW cm-2 at 600 ℃ to the conventional ionic conducting electrolyte-based SOFCs. Furthermore, the mechanism for surface conductivity enhancement has been discussed. These findings reveal an alternative methodology to prepare materials with significant impacts on advanced R&D SOFC technology.
|
|
| 8. |
|
|
| 9. |
- Ma, Ying, 1983-
(författare)
-
Ceria-based Nanostructured Materials for Low-Temperature Solid Oxide Fuel Cells
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As one of the most efficient and environmentally benign energy conversion devices, solid oxide fuel cells (SOFC) have attracted much attention in recent years. Conventional SOFC with yttria-stabilized zirconia as electrolyte require high operation temperature (800-1000 °C), which causes significant problems like material degradation, as well as other technological complications and economic barrier for wider applications. Therefore, there is a broad interest in reducing the operation temperature of SOFCs. One of the most promising ways to develop low-temperature SOFCs (LTSOFC) is to explore effective materials for each component with improved properties. So in this thesis, we are aiming to design and fabricate ceria-based nanocomposite materials for electrolyte and electrodes of LTSOFC by a novel nanocomposite approach. In the first part of the thesis, novel core-shell doped ceria/Na2CO3 nanocomposite was fabricated and investigated as electrolytes materials of LTSOFC. Two types of doped ceria were selected as the main phase for nanocomposite: samarium doped ceria (SDC) and calcium doped ceria (CDC). The core-shell SDC/Na2CO3 nanocomposite particles are smaller than 100 nm with amorphous Na2CO3 shell of 4~6 nm in thickness. The ionic conductivity of nanocomposite electrolytes were investigated by EIS and four-probe d.c. method, which demonstrated much enhanced ionic conductivities compared to the single phase oxides. The thermal stability of such nanocomposite has also been investigated based on XRD, BET, SEM and TGA characterization after annealing samples at various temperatures. Such nanocomposite was applied in LTSOFCs with an excellent power density of 0.8 Wcm-2 at 550 °C. The high performances together with notable thermal stability prove the doped ceria/Na2CO3 nanocomposite as a potential electrolyte material for long-term LTSOFCs. In the second part of the thesis, a novel template-, surfactant-free chemical synthetic route has been successfully developed for the controlled synthesis of hierarchically structured CeO2 with nanowires and mesoporous microspheres morphologies. The new synthetic route was designed by utilizing the chelate formation between cerium ion and various carboxylates forms of citric acid. Then, hierarchically structured cerium oxide with morphologies of nanowires and mesoporous microspheres can be obtained by thermal decomposition of the two kinds of precursors. Moreover, by doping with desired elements, SDC nanowires and SDC-CuO mesoporous microspheres were prepared and used for electrolyte and anode materials, respectively, based on their unique properties depending on their morphologies. When SDC nanowires/Na2CO3 composite were applied as electrolyte for single SOFC, and it exhibited maximum power density of 522 mWcm-2 at 600 °C, which is much better than the state-of-the-art SOFCs using doped ceria as electrolytes. Besides, the mesoporous CuO-SDC composite anode was synthesized by our microwave-assisted method, which shows good phase homogeneity of both SDC and CuO. When it was applied for fuel cells, the cell had better performance than conventional CuO-SDC anode prepared by solid state method. The whole work of this thesis aims to provide a new methodology for the entire SOFC community. It is notable that our work has attracted considerable attention after publication of several attached papers. The results in this thesis may benefit the development of LTSOFC and expand the related research to a new horizon.
|
|
| 10. |
|
|
