The root cause of the rate performance improvement after metal doping: A case study of LiFePO4

Chang Kyoo Park, Sung Bin Park, Ji Hun Park, Ho Chul Shin, Won Il Cho, Ho Jang

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Abstract

This study investigates a root cause of the improved rate performance of LiFePO4 after metal doping to Fesites. This is because the metal doped LiFePO4/C maintains its initial capacity at higher C-rates than undoped one. Using LiFePO4/C and doped LiFe0.97M 0.03PO4/C (M=Al3+, Cr3+, Zr 4+), which are synthesized by a mechanochemical process followed by one-step heat treatment, the Li content before and after chemical delithiation in the LiFePO4/C and the binding energy are compared using atomic absorption spectroscopy (AAS) and X-ray photoelectron spectroscopy (XPS). The results from AAS and XPS indicate that the low Li content of the metal doped LiFePO4/C after chemical delithiation is attributed to the low binding energy induced by weak Li-O interactions. The improved capacity retention of the doped LiFePO4/C at high discharge rates is, therefore, achieved by relatively low binding energy between Li and O ions, which leads to fast Li diffusivity.

Original languageEnglish
Pages (from-to)921-926
Number of pages6
JournalBulletin of the Korean Chemical Society
Volume32
Issue number3
DOIs
Publication statusPublished - 2011 Mar 20

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Keywords

  • Binding energy
  • Doping
  • LiFePO
  • Rate performance
  • XPS

ASJC Scopus subject areas

  • Chemistry(all)

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