| 1. |
- Wang, Baoyuan, et al.
(författare)
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Fast ionic conduction in semiconductor CeO2-delta electrolyte fuel cells
- 2019
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Ingår i: NPG ASIA MATERIALS. - : Nature Publishing Group. - 1884-4049 .- 1884-4057. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Producing electrolytes with high ionic conductivity has been a critical challenge in the progressive development of solid oxide fuel cells (SOFCs) for practical applications. The conventional methodology uses the ion doping method to develop electrolyte materials, e.g., samarium-doped ceria (SDC) and yttrium-stabilized zirconia (YSZ), but challenges remain. In the present work, we introduce a logical design of non-stoichiometric CeO2-delta based on non-doped ceria with a focus on the surface properties of the particles. The CeO2-delta reached an ionic conductivity of 0.1 S/cm and was used as the electrolyte in a fuel cell, resulting in a remarkable power output of 660 mW/cm(2) at 550 degrees C. Scanning transmission electron microscopy (STEM) combined with electron energy-loss spectroscopy (EELS) clearly clarified that a surface buried layer on the order of a few nanometers was composed of Ce3+ on ceria particles to form a CeO2-delta@CeO2 core-shell heterostructure. The oxygen deficient layer on the surface provided ionic transport pathways. Simultaneously, band energy alignment is proposed to address the short circuiting issue. This work provides a simple and feasible methodology beyond common structural (bulk) doping to produce sufficient ionic conductivity. This work also demonstrates a new approach to progress from material fundamentals to an advanced low-temperature SOFC technology.
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| 2. |
- Yun, Sining, et al.
(författare)
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Enhanced Performance of Supported HfO2 Counter Electrodes for Redox Couples Used in Dye-Sensitized Solar Cells
- 2014
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 7:2, s. 442-450
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Tidskriftsartikel (refereegranskat)abstract
- Mesoporous-graphitic-carbon-supported HfO2 (HfO2-MGC) nanohybrids were synthesized by using a soft-template route. Characterization and a systematic investigation of the catalytic properties, stability, and catalytic mechanism were performed for HfO2-MGC counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The new HfO2-MGC as a CE in DSSCs showed a surprisingly high efficiency of 7.75% for the triiodide/iodide redox couple and 3.69% for the disulfide/thiolate redox couple, greater than the Pt electrode in the corresponding electrolyte system, which opens up a possibility for its practical application.
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| 3. |
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| 4. |
- Yun, Sining, et al.
(författare)
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Pt-Free Counter Electrode for Dye-Sensitized Solar Cells with High Efficiency
- 2014
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 26:36, s. 6210-6237
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Tidskriftsartikel (refereegranskat)abstract
- Dye-sensitized solar cells (DSSCs) have attracted widespread attention in recent years as potential cost-effective alternatives to silicon-based and thin-film solar cells. Within typical DSSCs, the counter electrode (CE) is vital to collect electrons from the external circuit and catalyze the I-3(-) reduction in the electrolyte. Careful design of the CEs can improve the catalytic activity and chemical stability associated with the liquid redox electrolyte used in most cells. In this Progress Report, advances made by our groups in the development of CEs for DSSCs are reviewed, highlighting important contributions that promise low-cost, efficient, and robust DSSC systems. Specifically, we focus on the design of novel Pt-free CE catalytic materials, including design ideas, fabrication approaches, characterization techniques, first-principle density functional theory (DFT) calculations, ab-initio Car-Parrinello molecular dynamics (CPMD) simulations, and stability evaluations, that serve as practical alternatives to conventional noble metal Pt electrodes. We stress the merits and demerits of well-designed Pt-free CEs, such as carbon materials, conductive polymers, transition metal compounds (TMCs) and their corresponding hybrids. Also, the prospects and challenges of alternative Pt catalysts for their applications in new-type DSSCs and other catalytic fields are discussed.
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| 5. |
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| 6. |
- Yun, Sining, et al.
(författare)
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Superior Catalytic Activity of Sub-5 mu m-Thick Pt/SiC Films as Counter Electrodes for Dye-Sensitized Solar Cells
- 2014
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Ingår i: ChemCatChem. - : Wiley. - 1867-3880 .- 1867-3899. ; 6:6, s. 1584-1588
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Tidskriftsartikel (refereegranskat)abstract
- Dye-sensitized solar cells with sub-5 mu m-thick Pt/SiC-P (1.79 at.% Pt), Pt/SiC-M (0.45 at.% Pt), and Pt/SiC-R (0.39 at.% Pt) counter electrode (CE) films fabricated by using three different processes produced power conversion efficiencies of 6.82, 7.64, and 7.04% that reached 86.5, 97.0, and 89.3 %, respectively, of the level obtained by using a print-Pt CE (7.88 %). These materials can reduce the cost of CEs and solve challenges involving Pt.
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