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| 2. |
- Gao, Zhan, et al.
(author)
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Development of methanol-fueled low-temperature solid oxide fuel cells
- 2011
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In: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 35:8, s. 690-696
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Journal article (peer-reviewed)abstract
- Low-temperature solid oxide fuel cell (SOFC, 300-600 degrees C) technology fueled by methanol possessing significant importance and application in polygenerations has been developed. Thermodynamic analysis of methanol gas-phase compositions and carbon formation indicates that direct operation on methanol between 450 and 600 degrees C may result in significant carbon deposition. A water steam/methanol ratio of 1/1 can completely suppress carbon formation in the same time enrich H(2) production composition. Fuel cells were fabricated using ceria-carbonate composite electrolytes and examined at 450-600 degrees C. The maximum power density of 603 and 431 mW cm(-2) was achieved at 600 and 500 degrees C, respectively, using water steam/methanol with the ratio of 1/1 and ambient air as fuel and oxidant. These results provide great potential for development of the direct methanol low-temperature SOFC for polygenerations.
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| 3. |
- Gao, Zhan, et al.
(author)
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Electrochemical Characterization on SDC/Na2CO3 Nanocomposite Electrolyte for Low Temperature Solid Oxide Fuel Cells
- 2011
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In: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 1533-4899. ; 11:6, s. 5413-5417
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Journal article (peer-reviewed)abstract
- Our previous work has demonstrated that novel core-shell SDC/Na2CO3 nanocomposite electrolyte possesses great potential for the development of low temperature (300-600 degrees C) solid oxide fuel cells. This work further characterizes the nanocomposite SDC/Na2CO3 electrochemical properties and conduction mechanism. The microstructure of the nanocomposite sintered at different temperatures was analyzed through scanning electron microscope (SEM) and X-ray diffraction (XRD). The electrical and electrochemical properties were studied. Significant conductivity enhancement was observed in the H-2 atmosphere compared with that of air atmosphere. The ratiocination of proton conduction rather than electronic conduction has been proposed consequently based on the observation of fuel cell performance. The fuel cell performance with peak power density of 375 mW cm(-2) at 550 degrees C has been achieved. A.C. impedance for the fuel cell under open circuit voltage (OCV) conditions illustrates the electrode polarization process is predominant in rate determination.
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| 4. |
- Gao, Zhan, et al.
(author)
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Preparation and characterization of Sm0.2Ce0.8O1.9/Na2CO3 nanocomposite electrolyte for low-temperature solid oxide fuel cells
- 2011
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In: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 36:6, s. 3984-3988
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Journal article (peer-reviewed)abstract
- Sm0.2Ce0.8O1.9 (SDC)/Na2CO3 nanocomposite synthesized by the co-precipitation process has been investigated for the potential electrolyte application in low-temperature solid oxide fuel cells (SOFCs). The conduction mechanism of the SDC/Na2CO3 nanocomposite has been studied. The performance of 20 mW cm(-2) at 490 degrees C for fuel cell using Na2CO3 as electrolyte has been obtained and the proton conduction mechanism has been proposed. This communication demonstrates the feasibility of direct utilization of methanol in low-temperature SOFCs with the SDC/Na2CO3 nanocomposite electrolyte. A fairly high peak power density of 512 mW cm(-2) at 550 degrees C for fuel cell fueled by methanol has been achieved. Thermodynamical equilibrium composition for the mixture of steam/methanol has been calculated, and no presence of C is predicted over the entire temperature range. The long-term stability test of open circuit voltage (OCV) indicates the SDC/Na2CO3 nanocomposite electrolyte can keep stable and no visual carbon deposition has been observed over the anode surface. Copyright (C) 2011, Hydrogen Energy Publications, LLC.
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| 5. |
- Raza, Rizwan, et al.
(author)
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Ce-0.8(SmZr)(0.2)O-2-carbonate nanocomposite electrolyte for solid oxide fuel cell
- 2014
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In: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 38:4, s. 524-529
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Journal article (peer-reviewed)abstract
- A nanocomposite Zr/Sm-codoped ceria electrolyte coated with K2CO3/Na2CO3 was synthesized by a coprecipitation method. The electrochemical study of the two-phase nanocomposite electrolytes with carbonate coated on the doped ceria shows high oxygen ion mobility at low temperatures (300-600 degrees C). The interface between the two constituent phases was studied by electrochemical impedance spectroscopy. Ionic conductivities were also measured with electrochemical impedance spectroscopy. The morphology and structure of composite electrolyte were characterized using field-emission scanning electron microscopy and X-ray diffraction. The fuel cell power density is 700 mW cm(-2), and an open-circuit voltage of 1.00 V is achieved at low temperatures (400-550 degrees C). This codoped approach with a second phase provides a good indication regarding overcoming the challenges of solid oxide fuel cell technology.
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| 6. |
- Raza, Rizwan, et al.
(author)
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LiAlO2-LiNaCO3 Composite Electrolyte for Solid Oxide Fuel Cells
- 2011
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In: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 1533-4899. ; 11:6, s. 5402-5407
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Journal article (peer-reviewed)abstract
- This paper reports a new approach to develop functional solid oxide fuel cells (SOFC) electrolytes based on nanotechnology and two-phase nanocomposite approaches using non-oxygen ion or proton conductors, e.g., lithium aluminate-lithium sodium carbonate, with great freedom in material design and development. Benefited by nanotechnology and nanocomposite technology, the lithium aluminate-lithium sodium carbonate two-phase composite electrolytes can significantly enhance the material conductivity and fuel cell performance at low temperatures, such as 300 degrees C-600 degrees C compared to non-nano scale materials. The conductivity mechanism and fuel cell functions are discussed to be benefited by the interfacial behavior between the two constituent phases in nano-scale effects, where oxygen ion and proton conductivity can be created, although there are no intrinsic mobile oxygen ions and protons. It presents a new scientific approach to design and develop fuel cell materials in breaking the structural limitations by using non-ionic conductors on the desired ions i.e., proton and oxygen ions, and creating high proton and oxygen ion conductors through interfaces and interfacial mechanism.
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