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Influence of carbonate-based additives on the electrochemical performance of Si NW anodes cycled in an ionic liquid electrolyte.
Date
2020
Abstract
Addition of electrolyte additives (ethylene or vinylene carbonate) is shown to dramatically improve the cycling stability and capacity retention (1600 mAh g-1) of Si nanowires (NWs) in a safe ionic liquid (IL) electrolyte (0.1LiTFSI-0.6PYR13FSI-0.3PYR13TFSI). We show, using postmortem SEM and TEM, a distinct difference in morphologies of the active material after cycling in the presence or absence of the additives. The difference in performance is shown by postmortem XPS analysis to arise from a notable increase in irreversible silicate formation in the absence of the carbonate additives. The composition of the solid electrolyte interphase (SEI) formed at the active material surface was further analyzed using XPS as a function of the IL components revealing that the SEI was primarily made up of N-, F-, and S-containing compounds from the degradation of the TFSI and FSI anions.
Supervisor
Description
peer-reviewed
Publisher
Citation
Nano Letters;20 (10), pp. 7011-7019
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Funding Information
European Research Council (ERC), European Union (EU), Science Foundation Ireland (SFI), Irish Research Council (IRC), European Union (EU), Horizon 2020