Operando electrochemical impedance spectroscopy and its application to commercial Li-ion batteries

Noel Hallemans, Widanalage Dhammika Widanage, Xinhua Zhu, Sanghamitra Moharana, warwic Rashid, Annick Hubin, John Lataire

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)
243 Downloads (Pure)

Abstract

Electrochemical impedance spectroscopy (EIS) is a non-invasive technique for examining kinetics of electrochemical systems. Applied to energy storage devices, the impedance contains information about the state-of-charge and state-of-health of a battery. Classical EIS measurements, as implemented in many cyclers, are restricted by two important assumptions: linearity and stationarity. However, Li-ion batteries are inherently nonlinear, and are nonstationary while under operation. Classical EIS can thus only be performed on batteries in steady-state, and hence, no information about batteries under operation can be extracted. In this article, operando EIS is introduced as a promising tool for measuring time-varying impedance data of Li-ion batteries. The mathematics behind the impedance extraction are detailed, starting from nonstationary and mildly nonlinear current and voltage data. The technique is then applied to reproducible experiments, while charging and discharging commercial Li-ion batteries, using a commercial potentiostat. The operando impedance is shown to be different from the classical impedance, and the nonlinear behaviour of the battery is studied. Applications of operando EIS are discussed, with the focus on the modelling of the operando impedance data through equivalent circuit models, revealing the evolution of the ECM parameters over time.
Original languageEnglish
Article number232005
Number of pages11
JournalJournal of Power Sources
Volume547
Issue number11
DOIs
Publication statusPublished - 1 Nov 2022

Bibliographical note

Funding Information:
The authors would like to thank the late Rik Pintelon for initiating this joint research project between the University of Warwick and the VUB. Special thanks to John Booth from SciMed for his professional help with the measurement set-up. This project was supported financially by the Eutopia mobility programme, the Fund for Scientific Research (FWO Vlaanderen) and the Flemish government, Belgium (grant number: METH1). The code for generating multisine signals and extracting the time-varying impedance from the measured data will be made available on demand by contacting the corresponding author.

Funding Information:
The authors would like to thank the late Rik Pintelon for initiating this joint research project between the University of Warwick and the VUB. Special thanks to John Booth from SciMed for his professional help with the measurement set-up. This project was supported financially by the Eutopia mobility programme, the Fund for Scientific Research (FWO Vlaanderen) and the Flemish government, Belgium (grant number: METH1 ).

Publisher Copyright:
© 2022 Elsevier B.V.

Copyright:
Copyright 2022 Elsevier B.V., All rights reserved.

Keywords

  • Dynamic EIS
  • Li-ion batteries
  • data-driven modelling
  • commercial cells
  • nonlinear behaviour
  • ECM

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