Anisotropic Ion Diffusion and Electrochemically Driven Transport in Nanostructured Block Copolymer Electrolytes
| Autor: | Steven Greenbaum, Lisa Cirrincione, Irune Villaluenga, Ksenia Timachova, Louis A. Madsen, Xi Jiang, Rajashree Bhattacharya, Nitash P. Balsara, Mallory Gobet, John Newman |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Anisotropic diffusion 020209 energy Analytical chemistry 02 engineering and technology Electrolyte Electrochemistry Surfaces Coatings and Films Ion Transmission electron microscopy 0202 electrical engineering electronic engineering information engineering Materials Chemistry Copolymer Lamellar structure Physical and Theoretical Chemistry Anisotropy |
| Zdroj: | The journal of physical chemistry. B. 122(4) |
| ISSN: | 1520-5207 |
| Popis: | Nanostructured block copolymer electrolytes have the potential to enable solid-state batteries with lithium metal anodes. We present complete continuum characterization of ion transport in a lamellar polystyrene-b-poly(ethylene oxide) copolymer/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) electrolyte as a function of salt concentration. Electrochemical measurements are used to determine the Stefan-Maxwell salt diffusion coefficients [Formula: see text], [Formula: see text], and [Formula: see text]. Individual self-diffusion coefficients of the lithium- and TFSI-containing species were measured by pulsed-field gradient NMR (PFG-NMR). The NMR data indicate that salt diffusion is locally anisotropic, and this enables determination of a diffusion coefficient parallel to the lamellae, D∥, and a diffusion coefficient through defects in the lamellae, D⊥. We quantify anisotropic diffusion by defining an NMR morphology factor and demonstrate that it is correlated to defect density seen by transmission electron microscopy. We find agreement between the electrochemically determined Stefan-Maxwell diffusion coefficients and the diffusion coefficient D⊥ determined by PFG-NMR. Our work indicates that the performance of nanostructured block copolymer electrolytes in batteries is strongly influenced by ion transport through defects. |
| Databáze: | OpenAIRE |
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