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Abstract Synthesizing solids in molten fluxes enables the rapid diffusion of soluble species at temperatures lower than in solid‐state reactions, leading to crystal formation of kinetically stable compounds. In this study, we demonstrate the effectiveness of mixed hydroxide and halide fluxes in synthesizing complex Sr/Ag/Se in mixed LiOH/LiCl. We have accessed a series of two‐dimensional Sr(Ag1−xLix)2Se2layered phases. With increased LiOH/LiCl ratio or reaction temperature, Li partially substituted Ag to form solid solutions of Sr(Ag1−xLix)2Se2withxup to 0.45. In addition, a new type of intergrowth compound [Sr3Se2][(Ag1−xLix)2Se2] was synthesized upon further reaction of Sr(Ag1−xLix)2Se2with SrSe. Both Sr(Ag1−xLix)2Se2and [Sr3Se2][(Ag1−xLix)2Se2] exhibit a direct band gap, which increases with increasing Li substitution (x). Therefore, the band gap of Sr(Ag1−xLix)2Se2can be precisely tuned via fine‐tuningxthat is controlled by only the flux ratio and temperature.
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Mathematical Modeling of High-Temperature Multiphase Solid/Molten Carbonate Membranes for CO 2 Capture
High-temperature solid/molten-carbonate composite represent an emerging class of CO2transport membranes to capture CO2from flue gas with advantages in flux density and selectivity over conventional solvent/sorbent- and polymer-based counterparts. While significant technical progress in these membranes has been made in the past years, a deeper fundamental understanding of CO2transport mechanisms is still limited. Aimed to bridge this gap, we here report a theoretical study on flux performances of four types of solid/molten-carbonate CO2transport membranes by analytical and numerical modeling. We found that analytical and numerical results are virtually identical for solids with single charge carrier. However, for mixed conducting solids, numerical methods are preferred since analytical methods cannot solve the nonlinear local concentrations of charge carriers. Application of numerical method to a new three-phase membrane containing a mixed conducting solid, a pure electron conducting solid and molten-carbonate reveals a ∼90% increase in CO2flux compared to the two-phase (mixed conducting solid and molten-carbonate) counterpart. The models presented here are expected to provide better fundamental insights and guidance for designing next-generation high-performance CO2transport membranes.
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- Award ID(s):
- 1924095
- PAR ID:
- 10204846
- Publisher / Repository:
- The Electrochemical Society
- Date Published:
- Journal Name:
- Journal of The Electrochemical Society
- Volume:
- 167
- Issue:
- 16
- ISSN:
- 0013-4651
- Page Range / eLocation ID:
- Article No. 164512
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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