Aging in Lithium-Ion Batteries: Experimental and Model Investigation of Harvested LiFePO4 and Mesocarbon Microbead Graphite Electrodes
2013 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 0019-4686, Vol. 110, 335-348 p.Article in journal (Refereed) Published
This study investigates aging in LiFePO4/mesocarbon microbead graphite cells that have been subjected to either a synthetic hybrid drive cycle or calendar aging, at 22 C. The investigation involves detailed examination and comparison of harvested fresh and aged electrodes. The electrode properties are determined using a physics-based electrochemical impedance spectroscopy (EIS) model that is fitted to three-electrode EIS measurements, with input from measured electrode capacity and scanning electrode microscopy (SEM). Results from the model fitting provide a detailed insight to the electrode degradation and is put into context with the behavior of the full cell aging. It was established that calendar aging has negligible effect on cell impedance, while cycle aging increases the impedance mainly due to structural changes in the LiFePO4 porous electrode and electrolyte decomposition products on both electrodes. Further, full-cell capacity fade is mainly a consequence of cyclable lithium loss caused by electrolyte decomposition.
Place, publisher, year, edition, pages
2013. Vol. 110, 335-348 p.
Lithium-ion battery, Aging, EIS modeling, LiFePO4, Graphite
IdentifiersURN: urn:nbn:se:kth:diva-122395DOI: 10.1016/j.electacta.2013.05.081ISI: 000329530300044ScopusID: 2-s2.0-84888320795OAI: oai:DiVA.org:kth-122395DiVA: diva2:622108
FunderStandUpSwedish Energy Agency
QC 20140120. Updated from "Accepted" to "Published".2013-05-202013-05-202014-05-12Bibliographically approved