The influence of fluorine doping on the structural and electrical properties of the LiFePO₄ powder

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• 作者：Dragana Jugović^a ; ^{dragana.jugovic@itn.sanu.ac.rs} ; ^{djugovic@vinca.rs} ; Miodrag Mitrić^b ; ^{mmitric@vinca.rs} ; Milo&scaron ; Milović^a ; ^{milos.milovic@itn.sanu.ac.rs} ; Nikola Cvjetićanin^c ; ^{nikola.cvj@ffh.bg.ac.rs} ; Bojan Jokić^d ; ^{bjokic@tmf.bg.ac.rs} ; Ana Umićević^b ; ^{umicev@vinca.rs} ; Dragan Uskoković^a ; ^{dragan.uskokovic@itn.sanu.ac.rs}
• 关键词：A. Powders ; solid state reaction ; B. Spectroscopy ; C. Electrical properties ; E. Electrodes
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：15 February 2017
• 年：2017
• 卷：43
• 期：3
• 页码：3224-3230
• 全文大小：882 K
• 卷排序：43

文摘

Low intrinsic electronic conductivity is the main disadvantage of LiFePO4 when used as a cathode material in lithium ion batteries. The paper offers experimental proofs of the theoretical prediction that fluorine doping of LiFePO4 can enhance its electrical conductivity. The LiFePO4 and fluorine-doped LiFePO4 olivine type, carbon-free powders are synthesized and examined. The crystal structure refinements in the Pnma space group reveal that doping with fluorine ions preserves the olivine structure, while reducing both the lattice parameters and the antisite defect, and increasing the crystallite size. A small amount of incorporated fluorine enhances the electrical conductivity from 4.6×10−7 S cm−1 to 2.3×10−6 S cm−1 and has a positive impact on the electrochemical performance. Several spectroscopy techniques (Mössbauer, FTIR, and Raman) reveal differences between the two powders and additionally support the findings of both the Rietveld refinement and the conductivity measurements.