Failure Study of Commercial LiFePO4 Cells in over-Discharge Conditions Using Electrochemical Impedance Spectroscopy

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Yadong Liu
  • Zhefei Li
  • Jian Xie
  • Hao He
  • Fan Xu

Detail(s)

Original languageEnglish
Pages (from-to)A620-A632
Journal / PublicationJournal of the Electrochemical Society
Volume161
Issue number4
Online published25 Feb 2014
Publication statusPublished - 2014
Externally publishedYes

Abstract

Electrochemical impedance spectroscopy (EIS) studies were carried out on commercial 18650 LiFePO4 cells at different States of Charge (SOCs) to investigate failure in over-discharge conditions. The charge/discharge curves, capacity, charge acceptance, temperature, and impedance were characterized and analyzed. The EIS results show that the de-convoluted Ohmic resistance, R0, solid electrolyte interphase (SEI) resistance, RSEI, and Warburg Coefficient, σ, change with cycle number in some patterns, indicating the occurrence of corrosion of the current collector, SEI breakdown/decomposition and reformation, and the development of diffusion barriers of Li+ in the electrode, respectively. These parameters, R0, RSEI,and σ are associated with failure and can be used as indicators of incoming failure. The EIS results from the three-electrode system verify that the EIS results from the two-electrode system (practical 18650 cells) are reliable, which lays the foundation for the use of electrochemical impedance on practical applications of LIB cells. Overall, electrochemical impedance spectroscopy can be used as an effective and reliable tool to monitor the state of health, predict incoming failure of the cell, and issue a warning before failure without disturbing the operation of the cell.

Citation Format(s)

Failure Study of Commercial LiFePO4 Cells in over-Discharge Conditions Using Electrochemical Impedance Spectroscopy. / Liu, Yadong; Liu, Qi; Li, Zhefei; Ren, Yang; Xie, Jian; He, Hao; Xu, Fan.

In: Journal of the Electrochemical Society, Vol. 161, No. 4, 2014, p. A620-A632.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review