Affiliation:
1. Department of Chemistry‐Ångström Laboratory Uppsala University Uppsala SE‐75121 Sweden
2. Karlsruher Institut für Technologie Institut für Angewandte Materialien (IAM) Herrmann‐von‐Helmholtz Platz 1 76344 Eggenstein‐Leopoldshafen Germany
Abstract
AbstractKnowledge about capacity losses related to the solid electrolyte interphase (SEI) in sodium‐ion batteries (SIBs) is still limited. One major challenge in SIBs is that the solubility of SEI species in liquid electrolytes is comparatively higher than the corresponding species formed in Li‐ion batteries. This study sheds new light on the associated capacity losses due to initial SEI formation, SEI dissolution and subsequent SEI reformation, charge leakage via SEI and subsequent SEI growth, and diffusion‐controlled sodium trapping in electrode particles. By using a variety of electrochemical cycling protocols, synchrotron‐based X‐ray photoelectron spectroscopy (XPS), gas chromatography coupled with mass spectrometry (GC‐MS), and proton nuclear magnetic resonance (1H‐NMR) spectroscopy, capacity losses due to changes in the SEI layer during different open circuit pause times are investigated in nine different electrolyte solutions. It is shown that the amount of capacity lost depends on the interplay between the electrolyte chemistry and the thickness and stability of the SEI layer. The highest capacity loss is measured in NaPF6 in ethylene carboante mixed with diethylene carbonate electrolyte (i.e., 5 µAh h−1/2pause or 2.78 mAh g·h−1/2pause) while the lowest value is found in NaTFSI in ethylene carbonate mixed with dimethoxyethance electrolyte (i.e., 1.3 µAh h−1/2pause or 0.72 mAh g·h−1/2pause).
Funder
Deutsche Forschungsgemeinschaft
Svenska Forskningsrådet Formas
Subject
General Physics and Astronomy,General Engineering,Biochemistry, Genetics and Molecular Biology (miscellaneous),General Materials Science,General Chemical Engineering,Medicine (miscellaneous)
Cited by
7 articles.
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