TY  - JOUR
AU  - Klein, Sven
AU  - Wrogemann, Jens Matthies
AU  - van Wickeren, Stefan
AU  - Harte, Patrick
AU  - Bärmann, Peer
AU  - Heidrich, Bastian
AU  - Hesper, Jakob
AU  - Borzutzki, Kristina
AU  - Nowak, Sascha
AU  - Börner, Markus
AU  - Winter, Martin
AU  - Kasnatscheew, Johannes
AU  - Placke, Tobias
TI  - Understanding the Role of Commercial Separators and Their Reactivity toward LiPF 6 on the Failure Mechanism of High‐Voltage NCM523 || Graphite Lithium Ion Cells
JO  - Advanced energy materials
VL  - 12
IS  - 2
SN  - 1614-6832
CY  - Weinheim
PB  - Wiley-VCH
M1  - FZJ-2021-05231
SP  - 2102599 -
PY  - 2022
AB  - NCM523 || graphite lithium ion cells operated at 4.5 V are prone to an early “rollover” failure, due to electrode cross-talk, that is, transition metal (TM = Mn, Ni, and Co) dissolution from NCM523 and deposition at graphite, subsequent formation of Li metal dendrites, and, in the worst case, generation of (micro-)short-circuits by dendrites growing to the cathode. Here, the impact of different separators on the high-voltage performance of NCM523 || graphite cells is elucidated focusing on the separators’ structural properties (e.g., membrane vs fiber) and their reactivity toward LiPF6 (e.g., ceramic-coated separators). First, the separator architecture has a major impact on cycle life. Fiber-structured separators can prevent the “rollover” failure by a more homogeneous deposition of TMs and formation of Li metal dendrites, thus, hindering penetration of dendrites to the cathode. In contrast, porous membrane-structured separators cannot prevent the cell failure due to inhomogeneous TM deposits/Li metal dendrites. Second, it is demonstrated that different types of ceramic-coated separators (Boehmite (γ-AlO(OH)) vs α-Al2O3) exhibit different reactivities toward LiPF6. While α-Al2O3 shows a minor reactivity toward LiPF6, the γ-AlO(OH) coating leads to in situ formation of the beneficial difluorophosphate anion in high amounts due the high reactivity toward LiPF6 decomposition, which significantly improves cycle life.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000725443500001
DO  - DOI:10.1002/aenm.202102599
UR  - https://juser.fz-juelich.de/record/903576
ER  -