Journal Article

FZJ-2019-05958

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Post-mortem analysis on LiFePO 4 |Graphite cells describing the evolution & composition of covering layer on anode and their impact on cell performance

Lewerenz, M. (Corresponding author)RWTH* ; Warnecke, A.RWTH* ; Sauer, D. U.FZJ*

2017
Elsevier New York, NY [u.a.]

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Please use a persistent id in citations: http://hdl.handle.net/2128/24278  doi:10.1016/j.jpowsour.2017.10.003

Abstract: During cyclic aging of lithium-ion batteries the formation of a μm-thick covering layer on top of the anode facing the separator is found on top of the anode. In this work several post-mortem analyses of cyclic aged cylindrical LFP|Graphite cells are evaluated to give a detailed characterization of the covering layer and to find possible causes for the evolution of such a layer. The analyses of the layer with different methods return that it consists to high percentage of plated active lithium, deposited Fe and products of a solid electrolyte interphase (SEI). The deposition is located mainly in the center of the cell symmetrical to the coating direction. The origin of these depositions is assumed in locally overcharged particles, Fe deposition or inhomogeneous distribution of capacity density. As a secondary effect the deposition on one side increases the thickness locally; thereafter a pressure-induced overcharging due to charge agglomeration of the back side of the anode occurs. Finally a compact and dense covering layer in a late state of aging leads to deactivation of the covered parts of the anode and cathode due to suppressed lithium-ion conductivity. This leads to increasing slope of capacity fade and increase of internal resistance.

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Contributing Institute(s):

1. Helmholtz-Institut Münster Ionenleiter für Energiespeicher (IEK-12)

Research Program(s):

1. 131 - Electrochemical Storage (POF3-131) (POF3-131)

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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