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- Wu, Liang-Ting, et al.
(författare)
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Prediction of SEI Formation in All-Solid-State Batteries : Computational Insights from PCL-based Polymer Electrolyte Decomposition on Lithium-Metal
- 2022
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Ingår i: Batteries & Supercaps. - : John Wiley & Sons. - 2566-6223. ; 5:9
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Tidskriftsartikel (refereegranskat)abstract
- Identifying the solid electrolyte interphase (SEI) components in all-solid-state lithium batteries (ASSLBs) is essential when developing strategies for improving this battery technology. However, a comprehensive understanding of the interfacial stability and decomposition reactions of solid polymer electrolyte with lithium metal anode remains a challenge, not least outside the dominating poly(ethylene oxide)-based materials. Here, we report the reactivity of an electrolyte system composed of a polyester (poly-epsilon-caprolactone, PCL) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt on Li (100) surface, and the subsequent SEI formation, using ab initio molecular dynamics (AIMD) simulations. The step-by-step electrolyte decomposition on the anode surface is monitored, and the resultant major SEI components are analyzed by Bader charges to correlate with X-ray photoelectron (XPS) signal. The presence of PCL at the Li surface promotes a rapid initial reduction of LiTFSI salt via cleavage of S-N and C-S bonds, and its complete dissociation and formation of major SEI components such as LiF, Li2O, Li2S, and C-containing species. Furthermore, a computational analysis of relevant XPS spectra is performed to support the degradation compounds.
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| 2. |
- Wu, Liang-Ting, et al.
(författare)
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Role of copper as current collectors in the reductive reactivity of polymers for anode-free lithium metal batteries : Insights from DFT and AIMD studies
- 2023
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Ingår i: Materials Today Physics. - : Elsevier. - 2542-5293. ; 38
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the role of current collectors (CCs) in the reductive reactivity of polymers on Li metal and the resultant solid electrolyte interphase (SEI) formation is essential for improving the performance of anode-free lithium metal batteries (AFLMBs). In this study, we have examined the reactivity of three polymeric hosts: poly(ethylene oxide) (PEO), poly(epsilon-caprolactone) (PCL), and poly(trimethylene carbonate) (PTMC) at Li metal supported on Cu surfaces (Li/Cu) using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. In particular, the effect of copper (Cu) CCs on polymer stability, electronic structure, and their reduction reactions is investigated and compared to that of pure Li (100) surface. Through time-dependent Bader charge transfer analysis, electron transfer is identified as the triggering factor for polymer reduction. Based on the simulations, we find that the Cu CCs have a significant influence on the charge distribution of the Li metals, which increases electron transfer to the polymers and thereby accelerates polymers reduction. This thereby leads to different reaction mechanisms as compared to on Li-metal. The findings suggest that utilization of Cu CCs avoids the production of CO molecules and improves the quality of the formed SEI layer.
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