2023 |
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In situ synthesis of extremely small, thermally stable perovskite nanocatalysts for high-temperature electrochemical energy devices
Mi Young Park, Jisu Shin, Sun-Young Park, Ji-eun Won, Jun Yeon Hwang, Seungki Hong, Si-Won Kim, Ji-Hoon Jang, Kyung Joong Yoon
Chemical Engineering Journal,
476,
23.11.15, published
High-temperature solid oxide cells (SOCs) offer one of the most efficient and versatile routes for producing electric power and H2. However, the practical use of nanomaterials in SOCs has been limited by their lack of thermal stability. In this study, we present an infiltration technique that enables the in situ synthesis of extremely small, thermally stable perovskite (Sm0.5Sr0.5)CoO3 nanocatalysts on the inner surface of porous SOC electrodes. We identified certain impurity phases, such as SrCO3, that cause fatal degradation and eliminated them using a rational complexation strategy optimized for individual constituent cations. Consequently, we fabricated ∼ 20 nm diameter, highly pure, single-phase nanocatalysts that achieved more than double the performance of a cell with standard (La,Sr)(Co,Fe)O3– and (La,Sr)CoO3-based air electrode. The cells stably operated during long-term tests in both the power generation and H2 production modes, with negligible degradation. Furthermore, we successfully scaled up this process to fabricate large-scale commercial cells using a fully automated process. The key findings of this study will resolve critical barriers with high-temperature nanomaterials and accelerate the commercialization of SOC technology.
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6 |
Annealing-Free Thioantimonate Argyrodites with High Li-Ion Conductivity and Low Elastic Modulus
Wo Dum Jung, Ji-Su Kim, Young Jung Kim, Hyeseong Jeong, Daseul Han, Kyung-Wan Nam, Docheon Ahn, Deok-Hwang Kwon, Hun-Gi Jung, Jong-Ho Lee, and Hyoungchul Kim
Advanced Functional Materials,
2023.3.9, Wiley, published
Although Li-ion superconducting sulfides have been developed as solid electrolytes (SEs) in all-solid-state batteries, their high deformability, which is inherently beneficial for room-temperature compaction, is overlooked and sacrificed. To solve this dilemmatic task, herein, highly deformable Li-ion superconductors are reported using an annealing-free process. The target thioantimonate, Li5.2Si0.2Sb0.8S4Br0.25I1.75, comprising bimetallic tetrahedra and bi-halogen anions is synthesized by two-step milling tuned for in situ crystallization, and exhibits excellent Li-ion conductivity (σion) of 13.23 mS cm−1 (averaged) and a low elastic modulus (E) of 12.51 GPa (aver-aged). It has a cubic argyrodite phase of ≈57.39% crystallinity with a halogen occupancy of ≈90.67% at the 4c Wyckoff site. These increased halogen occupancy drives the Li-ion redistribution and the formation of more Li vacancies, thus facilitating Li-ion transport through inter-cage pathway. Also, the facile annealing-free process provides a unique glass-ceramic structure advantageous for high deformability. These results represent a record-breaking milestone from the combined viewpoint of σion and E among promising SEs. Electrochemical characterization, including galvanostatic cycling tests for 400 h, reveals that this material displays reasonable electrochemical stability and cell performance (150.82 mAh g−1 at 0.1C). These achievements shed light on the synthesis of practical SEs suffice both σion and E requirements. |
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Atomically dispersed platinum electrocatalysts supported on gadolinia-doped ceria nanoparticles for practical high-temperature solid oxide cells
Jihong Min, Haewon Seo, Jisu Shin, Mi Young Park, Sun-Young Parkd, Haneul Choi, Soohyung Park, Sungeun Yang, Hye Jung Chang, Jongsup Hong and Kyung Joong Yoon
Journal of Materials Chemistry A,
2023.10.30, published
Atomically dispersed catalysts provide excellent catalytic properties and atom utilization efficiency, but their high-temperature application has been limited by their low thermal stability. Herein, we report atomically dispersed Pt catalysts that are both highly active and thermally stable in fuel cells and electrolyzers operating above 600 °C. We developed a urea-based chemical synthetic method that strongly anchors atomic-scale Pt species on the surface of ceria nanoparticles and prevents their agglomeration at high temperatures. Doping the ceria with gadolinia further enhances their catalytic properties by increasing the oxygen vacancy concentration and promoting the oxygen exchange kinetics. This process enables in situ synthesis within the porous electrode of realistic solid oxide cells and significantly improves the power output and H2 production rate in fuel cell and electrolysis modes, respectively. Furthermore, this electrode stably operated without noticeable degradation during a long-term evaluation, thus proving the excellent thermal stability of atomically dispersed Pt/ceria catalysts.
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Advancing towards ready-to-use solid oxide fuel cells: 5 minute cold start-up with high-power performance
Hyeseong Jeong, Channyung Lee, Ji-Won Son, Seung Yong Lee, Kyung Joong Yoon, Dongwook Shin, Mansoo Choi, Sung Soo Shin, and Hyoungchul Kim
J. Mater. Chem. A,
11,
2023.03.20, Journal of Materials Chemistry A, published
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Structural mapping and tuning of mixed halide ions in amorphous sulfides for fast Li-ion conduction and high deformability
Ji-Su Kim, Young Jung Kim, Daseul Han, Kyung-Wan Nam, Gihan Kwon, Tae Wook Heo, Hun-Gi Jung, Kyung Joong Yoon, and Hyoungchul Kim
J. Mater. Chem. A,
11,
2023.03.20, Journal of Materials Chemistry A, published
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열람중 |
Exsolution of Ru Nanoparticles on BaCe0.9Y0.1O3-δ Modifying Geometry and Electronic Structure of Ru for Ammonia Synthesis Reaction Under Mild Conditions
Hayoung Kim, Asif Jan, Deok-Hwang Kwon, Ho-Il Ji, Kyung Joong Yoon, Jong-Ho Lee, Yongseok Jun, Ji-Won Son, and Sungeun Yang
Small,
19,
Wiley, published
- Green ammonia is a carbon-free energy carrier and storage medium synthesized using green hydrogen and an active catalyst. - The catalytic activity of ammonia synthesis can be improved by controlling the geometry and electronic structure of the active species through an exsolution process. - Ru nanoparticles exsolved on a BaCe0.9Y0.1O3-δ support exhibit high activity and uniform size distribution, and are well-anchored to the support with in-plane epitaxy. The electronic structure of Ru is modified by in situ Ba promoter accumulation.
(Note that this is a summary of the abstract using chatGPT) |
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한국과학기술연구원 홈페이지
https://onlinelibrary.wiley.com/doi/full/10.1002/smll.202205424
138회 연결
PUBLICATION 