Studies on LiFePO4 as cathode material using impedance spectroscopy

Jan Philipp Schmidt, Thorsten Chrobak, Moses Ender, Jörg Illig, Dino Klotz, Ellen Ivers-Tiffée

Research output: Contribution to journalArticlepeer-review

Abstract

Lithium iron phosphate is a promising cathode material for the use in hybrid electrical vehicles (HEV) meeting the demands of good stability during cycling and safe operation due to reduced risk of thermal runaway. However, slow solid state diffusion and poor electrical conductivity reduce power capability. For further improvement, the identification of the rate determining processes is necessary. Electrochemical impedance spectroscopy (EIS) has proven to be a powerful tool for the characterization of electrochemical systems. In this contribution a deconvolution of the impedance with the distribution of relaxation times (DRTs) is used to obtain a better resolution in frequency domain. Therewith, the relevant loss processes are identified and an impedance model is developed. Using DRT and CNLS-fit allows the determination of time constants and polarization resistances of all relevant loss processes. Furthermore, their temperature behavior is studied and a physical interpretation is provided.

Original languageEnglish
Pages (from-to)5342-5348
Number of pages7
JournalJournal of Power Sources
Volume196
Issue number12
DOIs
Publication statusPublished - Jun 15 2011

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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