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

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    109 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

    Bibliographical note

    Funding Information:
    The authors are grateful for financial support from the Korea Science and Engineering Foundation (KOSEF), through the Research Center for Energy Conversion & Storage.

    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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