| 41. |
- Jing, Yifu, et al.
(författare)
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Synthesis and electrochemical performances of linicuzn oxides as anode and cathode catalyst for low temperature solid oxide fuel cell
- 2012
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Ingår i: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 1533-4899. ; 12:6, s. 5102-5105
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Tidskriftsartikel (refereegranskat)abstract
- Low temperature solid oxide fuel cell (LTSOFC, 300-600 °C) is developed with advantages compared to conventional SOFC (800-1000 °C). The electrodes with good catalytic activity, high electronic and ionic conductivity are required to achieve high power output. In this work, a LiNiCuZn oxides as anode and cathode catalyst is prepared by slurry method. The structure and morphology of the prepared LiNiCuZn oxides are characterized by X-ray diffraction and field emission scanning electron microscopy. The LiNiCuZn oxides prepared by slurry method are nano Li 0.28Ni 0.72O, ZnO and CuO compound. The nano-crystallites are congregated to form ball-shape particles with diameter of 800-1000 nm. The LiNiCuZn oxides electrodes exhibits high ion conductivity and low polarization resistance to hydrogen oxidation reaction and oxygen reduction reaction at low temperature. The LTSOFC using the LiNiCuZn oxides electrodes demonstrates good cell performance of 1000 mW cm -2 when it operates at 470 °C. It is considered that nano-composite would be an effective way to develop catalyst for LTSOFC.
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| 42. |
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| 43. |
- Khan, M. Ajmal, et al.
(författare)
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Effect of titania concentration on the grain boundary conductivity of calcium-doped ceria electrolyte
- 2014
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Ingår i: Ceramics International. - : Elsevier BV. - 0272-8842 .- 1873-3956. ; 40:7, s. 9775-9781
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Tidskriftsartikel (refereegranskat)abstract
- A solid-state technique was used to synthesize ceria-based (CDC-xT, in which x=0-1 mol%) solid electrolyte ceramics. The effects of doping the ceramic solid electrolyte (CDC) with titanium oxide were studied with regard to densification, crystal structure, morphology, electro-impedance spectroscopy and fuel cell performance. TiO2 doping afforded materials a 95% relative density at 940 degrees C, approximately 200 degrees C lower than the temperature required without titanium oxide. The addition of titanium oxide (TiO2) reduced the CDC sintering temperature and significantly improved the grain boundary conduction. The minimum grain boundary resistivity was obtained at 0.8 mol% TiO2. X-ray diffraction (XRD) results showed that the lattice parameters enhanced with increased titanium oxide concentrations up to 0.8 mol%, revealing the solubility limit for Caria's fluorite structure. The optimum doping level (0.8 mol%) is provided maximum conductivity. Conductivities were measured using EIS (Electrochemical Impedance Spectroscopy) with a two-probe method, and the activation energies were calculated using the Arrhenius plots. The maximum power density (660 mW/cm(2)) was achieved with CDC 0.8T electrolyte at 650 degrees C using LiCuZnNi oxide electrodes.
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| 44. |
- Lapa, C. M., et al.
(författare)
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Synthesis and characterization of composite electrolytes based on samaria-doped ceria and Na/Li carbonates
- 2010
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 35:7, s. 2953-2957
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Tidskriftsartikel (refereegranskat)abstract
- Samaria-doped ceria-based composites with a 2:1 addition of Li and Na carbonates (or simple Na carbonate as admixture) were prepared mixing nanosized powders of the ceramic phase with the remaining constituents. Samples fired at relatively low temperatures (below 700 degrees C) were characterized by X-ray diffraction, scanning electron microscopy combined with energy dispersive spectroscopy and impedance spectroscopy in air. These composites showed a complex but homogeneous distribution of both phases, with one ceramic skeleton of bonded nanosized grains surrounded by the carbonate-based phase. Impedance spectroscopy data was used to confirm the impressive electrical conductivity of these materials, but also to put into evidence the complex nature of the charge transport process, clearly deviating from classical electrolytes.
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| 45. |
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| 46. |
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| 47. |
- Lima, Raquel Bohn, et al.
(författare)
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Direct lignin fuel cell for power generation
- 2013
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:15, s. 5083-5089
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Tidskriftsartikel (refereegranskat)abstract
- Lignin, the second most abundant component after cellulose in biomass, has been examined in this study as a fuel for direct conversion into electricity using direct carbon fuel cells (DCFC). Two different types of industrial lignins were investigated: Lignosulfonate (LS) and Kraft lignin (KL), in their commercial forms, after their blending with commercial active carbon (AC) or after alteration of their structures by a pH adjustment to pH 10. It was found that the open circuit voltage (OCV) of the DCFC could reach around 0.7 V in most of the trials. Addition of active carbon increased the maximum current density from 43-57 to 83-101 mA cm(-2). The pH adjustment not only increased the maximum current density but also reduced the differences between the two types of lignins, resulting in an OCV of 0.68-0.69 V and a maximum current density of 74-79 mA cm(-2) from both lignins. Typical power density was 12 (for KL + AC) and 24 mW cm(-2) (for LS + AC). It is concluded that a direct lignin fuel cell is feasible and the lignin hydrophilicity is critical for the cell performance.
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| 48. |
- Lima, Raquel B., et al.
(författare)
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Direct lignin fuel cell for power generation
- 2011
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Ingår i: 16th International Symposium on Wood, Fiber and Pulping Chemistry. ; , s. 257-262
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Konferensbidrag (refereegranskat)abstract
- Lignin, the second most abundant component after cellulose in biomass, has been examined in this study as a fuel for a direct conversion into electricity using direct carbon fuel cell (DCFC). Two different types of industrial lignins were investigated: lignosulphonate (LS) and kraft lignin (KL), either directly in their commercial forms, after their blending with commercial active carbon (AC) or after alternation of their structures by a pH adjustment to pH 10. It has been found that the open circuit voltage (OCV) of the DCFC could reach around 0.7 V in most of the trials. Addition of active carbon increased the maximum current density from 43∼57 to 85∼101 mA/cm 2. The pH adjustment not only increased the maximum current density but also reduced the differences between the two types of lignins, resulting in an OCV of 0.680-0.699 V and a maximum current density of 74∼79 mA/cm 2 from both lignins. Typical power density was 12 (for KL +AC) and 24 mW cm -2 (for LS +AC). It has been concluded that a direct lignin fuel cell is feasible and the lignin hydrophilicity is critical for the cell performance.
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| 49. |
- Ling, Yifu, et al.
(författare)
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An improved synthesis method of ceria-carbonate based composite electrolytes for low-temperature SOFC fuel cells
- 2013
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 38:36, s. 16532-16538
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Tidskriftsartikel (refereegranskat)abstract
- SDC-carbonate composite electrolytes for low-temperature Solid Oxide Fuel Cells (LTSOFC) have been synthesized by an improved freeze drying method based on the formation of lanthanide citrate complex solution/gel. This method can not only maintain small particle sizes in composite, but also control the carbonate composition precisely. To optimize the electrochemical performance of the composite electrolytes, SDC-carbonate samples with different carbonate contents were prepared and investigated. SEM, EDS, MPD and XRD analyses were applied to characterize the morphology and carbonate content and EIS was used to determine the ionic conductivity of the electrolyte. The highest conductivity achieved was 400 mS/cm at 600 degrees C.
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| 50. |
- Liu, Qinghua, et al.
(författare)
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Advanced electrolyte-free fuel cells based on functional nanocomposites of a single porous component : analysis, modeling and validation
- 2012
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:21, s. 8036-8040
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Tidskriftsartikel (refereegranskat)abstract
- Recently, a fuel cell device constructed with only one layer composited of ceria-based nanocomposites (typically, lithium nickel oxide and gadolinium doped ceria (LiNiO2-GDC) composite materials), called an electrolyte-free fuel cell (EFFC), was realized for energy conversion by Zhu et al. The maxium power density of this single-component fuel cell is 450 mW cm(-2) at 550 degrees C when using hydrogen fuel. In this study, a model was developed to evaluate the performance of an EFFC. The kinetics of anodic and cathodic reactions were modeled based on electrochemical impedance spectroscopy (EIS) measurements. The results show that both of the anodic and cathodic reactions are kinetically fast processes at 500 degrees C. Safety issues of an EFFC using oxidant and fuels at the same time without a gas-tight separator were analyzed under open circuit and normal operation states, respectively. The reaction depth of anodic and cathodic processes dominated the competition between surface electrochemical and gas-phase reactions which were effected by the catalytic activity and porosity of the materials. The voltage and power output of an EFFC were calculated based on the model and compared with the experimental results.
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