Change search
ReferencesLink to record
Permanent link

Direct link
Uneven Film Formation across Depth of Porous Graphite Electrodes in Cycled Commercial Li-Ion Batteries
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.ORCID iD: 0000-0003-4901-5820
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. Scania CV AB, Sweden.
Show others and affiliations
2015 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 1, 90-100 p.Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
2015. Vol. 119, no 1, 90-100 p.
Keyword [en]
Capacity Fade, Impedance Spectroscopy, Postmortem Analysis, Thin-Film, Tof-Sims, Electrochemical Characterization, Photoelectron-Spectroscopy, Lithium Intercalation, Mass-Spectrometry, Aging Mechanisms
National Category
Other Chemistry Topics
URN: urn:nbn:se:kth:diva-160750DOI: 10.1021/jp509665eISI: 000347744700012ScopusID: 2-s2.0-84920651710OAI: diva2:791782
Swedish Energy Agency

QC 20150302

Available from: 2015-03-02 Created: 2015-02-27 Last updated: 2015-03-02Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Klett, MatildaSvens, PontusLindbergh, GöranWreland Lindström, Rakel
By organisation
Applied Electrochemistry
In the same journal
The Journal of Physical Chemistry C
Other Chemistry Topics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 96 hits
ReferencesLink to record
Permanent link

Direct link