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- Degradation mechanisms (1)
- Instrumental Isotope Fractionation (1)
- Isotope ratios (1)
- Isotopic tracing (1)
- LCO (1)
- LiCoO2 cathodes (1)
- Lithium isotope fractionation (1)
- Lithium isotopes (1)
- Lithium-ion batteries (1)
- MCICPMS (1)
Organisationseinheit der BAM
Instrumental Isotopic Fractionation (IIF) is the fractionation of
isotopes within the mass spectrometer, resulting in a deviation
of the measured isotope ratio from the true isotope ratio in a
sample. The foremost challenge in obtaining highly precise and
accurate absolute isotope ratio measurements lies in
implementing adequate corrections for IIF. The causes of IIF are
not yet completely understood and differ according to the type
of instrument. We are using certified isotope reference
materials to investigate the IIF behavior in in different types of
ICPMS instruments with different mass separation devices
including double focusing sector field (single and multicollector),
quadrupole filter and time-of-flight ICPMS.
Aging in lithium-ion batteries (LIBs) degrades performance and hinders sustainability, demanding advanced diagnostics for early failure prediction. We investigate lithium isotope fractionation (LIF) as an innovative probe of degradation in lithium cobalt oxide (LCO) coin cells aged over 0−700 cycles. High-precision multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) quantified δ7Li variations across cell stages: non-cycled (0 cycles), newly formed (5 cycles), semi-aged (250 cycles), and fully aged (700 cycles). During early cycling (≤ 45 cycles), chemical processes drive 7Li enrichment at the anode (δ7Li vs LSVEC = +12 ‰) through solid electrolyte interphase (SEI) formation, while the cathode depletes in 7Li (δ7Li vs LSVEC = −0.7 ‰). Beyond 45 cycles, electric field-induced migration predominates, promoting 6Li intercalation into the anode and increasing the δ7Li of the cathode by 8.1 ‰. Mass balance verifies isotope conservation, attributing shifts to redistribution and trapping. Complementary electrochemical impedance spectroscopy (EIS) and X-ray absorption spectroscopy and diffraction confirm SEI expansion, cobalt oxidation, lattice shrinkage, and changes in electrode structure, corroborating LIF trends. Notably, a δ7Li inflection at approximately 270 cycles anticipates end-of-life by 70 cycles, surpassing traditional methods in sensitivity. LIF emerges as a predictive indicator of aging mechanisms, informing optimized designs for durable LIBs.
