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Uneven Film Formati...
Uneven Film Formation across Depth of Porous Graphite Electrodes in Cycled Commercial Li-Ion Batteries
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- Klett, Matilda (författare)
- KTH,Tillämpad elektrokemi
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- Svens, Pontus (författare)
- KTH,Tillämpad elektrokemi,Scania CV AB, Sweden
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Tengstedt, Carl (författare)
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Seyeux, Antoine (författare)
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Swiatowska, Jolanta (författare)
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- Lindbergh, Göran (författare)
- KTH,Tillämpad elektrokemi
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- Wreland Lindström, Rakel (författare)
- KTH,Tillämpad elektrokemi
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(creator_code:org_t)
- 2014-12-24
- 2015
- Engelska.
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 119:1, s. 90-100
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- A critical aging mechanism in lithium-ion batteries is the decomposition of the electrolyte at the negative electrode forming a solid electrolyte interphase (SEI) layer that increases impedance and consumes cyclable lithium. In contrast to the typical nanometer SEI layer generally discussed, this paper reports on the formation of a micrometer thick film on top of and within the upper part of a porous graphite electrode in a deep-cycled commercial cylindrical LiFePO4/graphite cell. Morphological, chemical, and electrochemical characterizations were performed by means of cross-sectional electron microscopy in combination with energy dispersive X-ray spectroscopy and focused ion-beam milling, time-of-flight secondary ion mass spectrometry, and electrochemical impedance spectroscopy (EIS) to evaluate the properties and impact of the uneven film. It is shown that the film is enriched in PO and carbonate species but is otherwise similar in composition to the thin SEI formed on a calendar-aged electrode and clogs the pores in the electrode closest to the separator. Performance evaluation by physics-based EIS modeling supports a local porosity decrease, impeding the effective electrolyte transport in the electrode. The local variation of electrode properties implies that current distribution in the porous electrode under these cycling conditions causes inefficient material utilization and sustained uneven electrode degradation.
Ämnesord
- NATURVETENSKAP -- Kemi -- Annan kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Other Chemistry Topics (hsv//eng)
Nyckelord
- Capacity Fade
- Impedance Spectroscopy
- Postmortem Analysis
- Thin-Film
- Tof-Sims
- Electrochemical Characterization
- Photoelectron-Spectroscopy
- Lithium Intercalation
- Mass-Spectrometry
- Aging Mechanisms
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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