61. |
- Qin, Haiying, et al.
(författare)
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Integration design of membrane electrode assemblies in low temperature solid oxide fuel cell
- 2012
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 37:24, s. 19365-19370
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, an integration design of membrane electrode assemblies in low temperature solid oxide fuel cells (LTSOFCs) is accomplished by using a mixed ionic-electronic conductor. The mixed ionic-electronic conductor is a composite material, LiNiCuZn oxides, Gd2O3 and Sm-doped CeO2 composited with Na2CO3 (LiNiCuZn oxides-NGSDC), which consists of ionic conductor, n-type and p-type semiconductors. The multi-phase composite material can also be used in single layer fuel cell (SLFC) to replace single-phase materials. A SLFC using the LiNiCuZn oxides-NSGDC composite exhibits an OCV of 1.05 V and maximum power density of 800 mW cm-2, which is comparable to the cell performance of conventional LTSOFCs and much higher than that of SLFC reported before. The reasons leading to the good performance are porous structure of electrode and the matching of ionic conductor and semiconductor.
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62. |
- Rafique, Asia, et al.
(författare)
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An efficient carbon resistant composite Ni0.6Zn0.4O2-delta-GDC anode for biogas fuelled solid oxide fuel cell
- 2019
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 438
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the fabrication of Ni0.6Zn0.4-Gd0.2Ce0.8O2-delta (NiZn-GDC) via a two-step wet chemical synthesis technique. This composite was found to be more thermally stable and carbon resistive under the intense reducing environment of biogas. This was confirmed by different characterization techniques. The maximum power density P-max, was achieved at 600 degrees C as 820 mW/cm(2) and 548 mW/cm(2) with hydrogen and biogas, respectively. Different characterization techniques have been performed, such as X-ray diffractometry (XRD), scanning electron microscopy (SEM/EDX), UV visible spectroscopy, and Raman spectroscopy. The XRD pattern by Rietveld refinement showed two-phase structures of the anode composite with an average crystallite size of 25 35 nm before and after reduction with methane. The optical band gap (E-g(opt)) of NiZn-GDC was calculated to be 2.24eV from the Tauc plot using absorbance data. The Nyquist plot was also drawn to study the AC electrochemical impedance spectra (EIS) of the nanocomposite anode from 450 degrees C to 600 degrees C in air. The maximum DC conductivity of 1.37 S/cm was observed at a temperature of 600 degrees C using the four-probe DC technique.
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63. |
- Rafique, Asia, et al.
(författare)
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Design and Modeling of a Fuel Cell System Using Biomass Feedstock as a Biofuel
- 2020
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Ingår i: Fuel Cells. - : Wiley. - 1615-6846 .- 1615-6854. ; 20:1, s. 89-97
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Tidskriftsartikel (refereegranskat)abstract
- This paper aims to model ceramic fuel cell system based on low-temperature planar solid oxide fuel cell (SOFC) different biogases fuels from multiple biomasses, that is, animal waste, redwood, rice husk and sugar cane. Biomass is a better choice for the generation of energy globally. Therefore, there is a focus on the most available biomass resources in the country that can be used as clean energy sources. This developed model is designed by thermodynamic analysis and electrochemical calculations using MATLAB. The designed model is a lumped parameter model based on the steady-state one-dimensional flow. In this model, all calculated power and flow rate values were kept as positive values. Also, the system is considered to be free of leaks, and heat loss is neglected. The operating temperature and pressure are assumed to be 500–700 °C and the partial pressure is set at three different pressures; P1 (1 bar), P2 (2 bar), and P3 (3 bar), respectively, and fuel utilization factor is 80%. It is observed that the best performance is obtained with animal-waste based biogas at 700 °C and P3 (3 bar).
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64. |
- Rafique, Asia, et al.
(författare)
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Multioxide phase-based nanocomposite electrolyte (M@SDC where M = Zn2+ / Ba2+/ La2+/Zr-2/Al3+) materials
- 2020
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Ingår i: Ceramics International. - : ELSEVIER SCI LTD. - 0272-8842 .- 1873-3956. ; 46:52, s. 6882-6888
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the development of a highly dense and stable electrolyte on the base of nanoionics oxide interface theory. This gives a comparative study of two-phase nanocomposite electrolytes that are developed for low temperature solid oxide fuel cells (LT-SOFCs). These nanocomposites are synthesised with different oxides, which are coated on the doped ceria that showed high oxide ion mobility for LT-SOFCs. These novel two-phase nanocomposite oxide ionic conductors (MCe0.8Sm0.2O2-MO2, where M = Zn2+/Ba2+/La3+/Zr2+/Al3+) were synthesised by a co-precipitation method. The interface study between these two phases was analysed by electrochemical impedance spectroscopy (EIS), while ionic conductivities were measured with DC conductivity (four probe method). The nanocomposite electrolytes exhibited higher conductivities with the increase of concentration of coated oxides but decreased at a certain level. The structural or morphological properties of the nanocomposite electrolytes were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The thermal stability was investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The maximum performance of 590 mW/cm(2) at 550 degrees C was obtained for the Zn@SDC based cell, and the rest of the coated samples Ba@SDC, La@SDC, Zr@SDC and Al@SDC based cells showed values of 550 mW/cm(2), 540 mW/cm(2), 450 mW/cm(2), 340 mW/cm(2), respectively, with hydrogen as a fuel. Therefore, the coated-SDC based nanocomposite materials are a good approach for lowering the operating temperature to achieve the challenges of the solid oxide fuel cells (SOFC). These two-phase nanocomposite electrolytes satisfy the all requirements which one electrolyte should have, like high ionic conduction, thermodynamic stability and negligible electronic conduction.
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65. |
- Rafique, Asia, et al.
(författare)
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Significance enhancement in the conductivity of core shell nanocomposite electrolytes
- 2015
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 5:105, s. 86322-86329
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Tidskriftsartikel (refereegranskat)abstract
- Today, there is great demand of electrolytes with high ionic conductivities at low operating temperatures for solid-oxide fuel cells. Therefore, a co-doped technique was used to synthesize a highly ionically conductive two phase nanocomposite electrolyte Sr/Sm-ceria-carbonate by a co-precipitation method. A significant increase in conductivity was measured in this co-doped Sr/Sm-ceria-carbonate electrolyte at 550 degrees C as compared to the more commonly studied samarium doped ceria. The fuel cell power density was 900 mW cm(-2) at low temperature (400-580 degrees C). The composite electrolyte was found to have homogenous morphology with a core-shell structure using SEM and TEM. The two phase core-shell structure was confirmed using XRD analysis. The crystallite size was found to be 30-60 nm and is in good agreement with the SEM analysis. The thermal analysis was determined with DSC. The enhancement in conductivity is due to two effects; co-doping of Sr in samarium doped ceria and it's composite with carbonate which is responsible for the core-shell structure. This co-doped approach with the second phase gives promise in addressing the challenge to lower the operating temperature of solid oxide fuel cells (SOFC).
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66. |
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67. |
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68. |
- Raza, Rizwan, et al.
(författare)
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A nanostructure anode (Cu0.2Zn0.8) for low-temperature solid oxide fuel cell at 400-600 oC
- 2010
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 195:24, s. 8067-8070
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Tidskriftsartikel (refereegranskat)abstract
- We developed a new nickel-free anode for a low-temperature solid oxide fuel cell (LTSOFC) that demonstrated an outstanding electrochemical output of 1000 mW cm(-2) at 550 degrees C. The nanostructure anode had good conductivity and was compatible with cerium oxide-based electrolytes. The performance of a single cell was comparable and or better than those using standard Ni-YSZ and Ni-SDC electrodes (anode). It may have applications for hydrocarbon-based fuel for preventing carbon deposition and replacing nickel in the anode of LTSOFCs.
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69. |
- Raza, Rizwan, 1980-, et al.
(författare)
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Advanced Multi-Fuelled Solid Oxide Fuel Cells (ASOFCs) Using Functional Nanocomposites for Polygeneration
- 2011
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Ingår i: Advanced Energy Materials. - Germany : Wiley-VCH Verlagsgesellschaft. - 1614-6832 .- 1614-6840. ; 1:6, s. 1225-1233
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Tidskriftsartikel (refereegranskat)abstract
- An advanced multifuelled solid oxide fuel cell (ASOFC) with a functional nanocomposite was developed and tested for use in a polygeneration system. Several different types of fuel, for example, gaseous (hydrogen and biogas) and liquid fuels (bio-ethanol and bio-methanol), were used in the experiments. Maximum power densities of 1000, 300, 600, 550 mW cm−2 were achieved using hydrogen, bio-gas, bio-methanol, and bio-ethanol, respectively, in the ASOFC. Electrical and total efficiencies of 54% and 80% were achieved using the single cell with hydrogen fuel. These results show that the use of a multi-fuelled system for polygeneration is a promising means of generating sustainable power.
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70. |
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