| 1. |
- 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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| 2. |
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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- Raza, Rizwan, et al.
(författare)
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Electrochemical study on co-doped ceria-carbonate composite electrolyte
- 2012
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 201, s. 121-127
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Tidskriftsartikel (refereegranskat)abstract
- A co-doped ceria-carbonate (Ce0.8Sm0.2-xCaxO2-delta-Na2CO3) has been synthesized by a co-precipitation method. The detailed electrochemical characterizations (e.g. impedance spectra, polarization curve and IV curves) of this composite material are reported and discussed. The two phase nanocomposite electrolytes with carbonate coated on the co-doped ceria displays dual (H+/O2-) ion conduction at low temperature (300-600 degrees C) in solid oxide fuel cell. The observed remarkable temperature-dependent of conductivity is attributed to the softening/melting of carbonate phase as the physical state of carbonate phase transforms from solid to molten state. Coexistence of various charge carriers, oxide phase composition, and the oxide-carbonate interfacial area are investigated by Raman spectra. The enhancement of conductivity is also discussed by the general mixing rule/percolation theory of composite interfaces. The co-doping with 2nd phase gives a good approach to realize challenges for solid oxide fuel cell.
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| 7. |
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| 8. |
- Zhu, Bin, et al.
(författare)
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A fuel cell with a single component functioning simultaneously as the electrodes and electrolyte
- 2011
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Ingår i: Electrochemistry communications. - : Elsevier BV. - 1388-2481 .- 1873-1902. ; 13:3, s. 225-227
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Tidskriftsartikel (refereegranskat)abstract
- A fuel cell device is realized by using a single component of lithium nickel oxide and gadolinium doped ceria (LiNiO2-GDC) composite material, a mixture of electronic and ionic conductors, when nickel foam and silver paste are attached to each surface of the single component pellet as current collectors. This simple fuel cell construction with only one component showed the same or even better performances compared to conventional three-component MEA (membrane electrolyte assembly) fuel cell using GDC as electrolyte. The maximum power density of 450 mW/cm(2) has been achieved at 550 degrees C for the single component fuel cell.
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| 9. |
- Zhu, Bin, 1956-, et al.
(författare)
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A new energy conversion technology joining electrochemical and physical principles
- 2012
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Ingår i: RSC Advances. - 2046-2069. ; 2:12, s. 5066-5070
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Tidskriftsartikel (refereegranskat)abstract
- We report a new energy conversion technology joining electrochemical and physical principles. This technology can realize the fuel cell function but built on a different scientific principle. The device consists of a single component which is a homogenous mixture of ceria composite with semiconducting materials, e.g. LiNiCuZn-based oxides. The test devices with hydrogen and air operation delivered a power density of 760mWcm(-2) at 550 degrees C. The device has demonstrated a multi-fuel flexibility and direct alcohol and biogas operations have delivered 300-500 mW cm(-2) at the same temperature. Device physics reveal a key principle similar to solar cells realizing the function based on an effective separation of electronic and ionic conductions and phases within the single-component. The component material multi-functionalities: ion and semi-conductions and bi-catalysis to H-2 or alcohol (methanol and ethanol) and air (O-2) enable this device realized as a fuel cell.
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| 10. |
- Zhu, Bin, et al.
(författare)
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A single-component fuel cell reactor
- 2011
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 36:14, s. 8536-8541
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Tidskriftsartikel (refereegranskat)abstract
- We report here a single-component reactor consisting of a mixed ionic and semi-conducting material exhibiting hydrogen-air (oxygen) fuel cell reactions. The new single-component device was compared to a conventional three-component (anode/electrolyte/cathode) fuel cell showing at least as good performance. A maximum power density of 300-600 mW cm(-2) was obtained with a LiNiZn-oxide and ceria-carbonate nanocomposite material mixture at 450-550 degrees C. Adding a redox catalyst element (Fe) resulted in an improvement reaching 700 mW cm(-2) at 550 degrees C.
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