Synthesis and electrochemical properties of olivine-type LiFePO4/C composite cathode material prepared from a poly(vinyl alcohol)-containing precursor

Nan Ji Yun, Hyung Wook Ha, Kyung Hee Jeong, Heon Yong Park, Keon Kim

Research output: Contribution to journalArticle

97 Citations (Scopus)

Abstract

Olivine structure LiFePO4/C composite powders are synthesized as cathode materials for Li-ion batteries via a conventional solid-state reaction. Improvement in electrochemical performance has been achieved by using poly(vinyl alcohol) as the carbon sources for the as-prepared materials. The influence of the heat treatment on the physical and the electrochemical properties of LiFePO4/C materials is investigated. To examine the effect of added carbon content on the properties of materials, a one-step heat treatment has been employed with control of the PVA content in the precursor. Six samples were prepared with 0, 1, 3, 5, 10 and 30 wt.% PVA added to the raw materials. The particle size of LiFePO4 decreases as the carbon content increases. Materials with medium carbon contents have a small charge-transfer resistance and thus exhibit superior electrochemical performance. Interestingly, for a LiFePO4/C composite with a low PVA content, an unusual plateau at 4.3 V is observed. It is considered that this is due to the Fe3+/Fe4+ redox reaction of Fe3+ compounds that are present as an impurity. For samples with a high PVA amount, a thicker carbon coating provides an obstacle to improve the electrochemical properties.

Original languageEnglish
Pages (from-to)1361-1368
Number of pages8
JournalJournal of Power Sources
Volume160
Issue number2 SPEC. ISS.
DOIs
Publication statusPublished - 2006 Oct 6

Keywords

  • Carbon coating
  • Cathode material
  • Li-ion batteries
  • LiFePO
  • Olivine
  • Poly(vinyl alcohol)

ASJC Scopus subject areas

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

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