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The research aims to identify distinct degradation mechanisms in lithium-ion cells using electrochemical impedance spectroscopy without relying on cycling history.

May 21, 20260 citationsOpen Access

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History-Independent Identification of Two Distinct Degradation Mechanisms in NMC/C-SiO Lithium-Ion Cells via Electrochemical Impedance Spectroscopy

MFManuel Maria Governa Figueirinha

Key Points

The research aims to identify distinct degradation mechanisms in lithium-ion cells using electrochemical impedance spectroscopy without relying on cycling history.
Conducted a history-independent identification of two pathways using a single 10-minute EIS measurement on 228 NMC/C-SiO cells.
Cells were tested across eight aging protocols at temperatures ranging from 0–40 °C.
Analyzed data using a prognostic model and various statistical techniques, including AUROC and F1 scores.
Identified LLI/SEI mechanism in 58.2% of tested cells at median state of health (SoH) of 103.3%.
Achieved AUROC of 0.951 for no-BoL LAM detection, with a low false positive rate of 7/151.
Confirmed a new SEI arc mechanism at a time constant of approximately 716 μs.

Abstract

History-independent identification of two mechanistically distinct degradation pathways (LLI/SEI and LAM) in NMC/C-SiO lithium-ion cells, from a single 10-minute EIS measurement at five states of charge — without cycling history, charge/discharge sweeps, or cell provenance. Validated on 228 NMC/C-SiO cells (LG INR18650HG2, 3. 0 Ah; Luh larger than v3 due to protocol regrouping — coldest group n = 33 vs n = 9 in v3). - LAM cohort: n = 26 (three-guard τ-jump criterion, stricter than v3 single guard). - LLI extended: 103/177 (added CYCLIC₀C + all PROFILE protocols). - NEW: No-BoL LAM detection (interₛocₛtdₘean, AUROC = 0. 951, LOPO F1 = 0. 818). - NEW: BoL-anchored LAM mode (d10ₘax, AUROC = 0. 998, FP = 1/151). - NEW: Stage-0 screen (Mₛlow, 157/177 cells at SoH = 103. 5%). - NEW: γ (τ) mechanism analysis — new SEI arc at τ ≈ 716 μs (f ≈ 222 Hz). - NEW: LOPO prospective validation (zero leakage, F1 = 0. 818 LAM, 0. 653 LLI). - NEW: Section 6. 5 Limitations. - Mslow prognostic model and DCIR analysis deferred to journal submission. - Dataset DOI corrected: 10. 35097/1969 → 10. 35097/krk531nmj4bsshha. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ KEY RESULTS (v4) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ LLI/SEI: 103/177 (58. 2%) at median SoH = 103. 3%, +7. 5 ckp lead to SoH < 80%. Eₐ = 0. 2027 eV (CYCLIC, R² = 0. 978) ; Eₐ = 0. 1464 eV (PROFILE). AUROC = 0. 747. LOPO F1 = 0. 653. LAM no-BoL: AUROC = 0. 951, FP = 7/151, LOPO F1 = 0. 818. No prior data needed. LAM BoL: AUROC = 0. 998, FP = 1/151, TP = 24/26. Stage-2: 26/26 TP, 0 FP in 151 non-LAM. SNR = 70–90×. Permutation p < 10⁻⁴. Mechanism: New SEI arc at τₙew ≈ 716 μs (f ≈ 222 Hz) confirmed by γ (τ) analysis. BMS path: Im (Z) @147 Hz + Re (Z) @1 kHz, 5 SoC, ~10 min. No DRT inversion required. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ RELATED WORKS ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preprint: DOI 10. 5281/zenodo. 18356226 τ₆₃ in PEM fuel cells (concurrent preprint, same author): DOI: 10. 1149/osf. io/hpu7y Dataset companion paper (Luh use the current DOI for reproduction. ) Competing interests: None. Funding: None declared.

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Manuel Maria Governa Figueirinha (Mon,) studied this question.

synapsesocial.com/papers/6a0ea1c1be05d6e3efb607c2 https://doi.org/https://doi.org/10.5281/zenodo.20277657

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