磷酸亚铁锂核壳结构材料的制备和电化学性能.pdf

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1、?23?1?Vol.23 No.12 0 0 9?2?CHINESE JOURNAL OF MATERIALS RESEARCHFebruary 2 0 0 9?(?(?)?110016)?/?/?,?.?,?,?.?,?,?.?,?,?,?TB321?1005-3093(2009)01-0022-05Synthesis and electrochemical property of LiFePO4withcore-shell structuresLIU ShuheWEN LeiBAI SuoLI FengWANG Zuoming(Shenyang National Laboratory fo

2、r Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016)Manuscript received March 5,2008;in revised form May 12,2008.*To whom correspondence should be addressed,Tel:(024)83978648,Email:ABSTRACTTwo types of core-shell structured cathode materials-pyrolytic carbon(P

3、yC)/LiFePO4and carbon nanofiber(CNF)/LiFePO4were synthesized by fluidized bed chemical vapor deposition methodand their electrochemical properties were explored.The PyC or CNF coating can effectively reduce theresistivity of LiFePO4,and greatly improved its charge-discharge capacity and cyclability.

4、Compared withPyC,the one dimensional structure and excellent mechanical performance of CNF make it more suitableas the conductive additive of LiFePO4.KEY WORDS inorganic non-metallic materials,LiFePO4,fluidized-bed,electrochemical property?,?LiCoO2?LiNiO2?LiMn2O4?,?(LiFePO4)?.?,LiFePO4?,?,?.?1997?,L

5、iFePO4?(?)?1,2.?,LiFePO4?,?/?;?,LiFePO4?LiFePO4/FePO4?,?,?.?LiFePO4?2008?3?5?;2008?5?12?.?:?,?,?.?,?,?,?.?,?,?LiFePO4?311.?,?LiFePO4?12,13?35,?LiFePO4?10,11.?,?,?LiFePO4?10,11;?LiFePO4?69.?,?LiFePO4?1?:?231?:?231?:?23?,?LiFePO4?.?LiFePO4?,?LiFePO4?.1?LiFePO4?,?,?,?(PyC/LiFePO4)?LiFePO4(CNF/LiFePO4)1

6、4.?,?25 rpm.?320 ml/min,?10%,?700?,?1040 min.?Ni(NO3)2 6H2O?,?LiFePO4(Ni/(Ni+LiFePO4)=1%)?,?.?550?,Ni(NO3)26H2O?Ni?.?(JSM6301F)?.?XRD(D/max 2500 PC,CuK)?(LabRam HR800,?1.96 eV)?(JEOL 2010 TEM)?.?TGDTA(STA449C Jupiter)?,?30700?,?9.?,?1 MPa.?.?94:6?,?,?70?12 h?.?12 mm?,?.?(MBraun,4069A)?.?,?(Celgard24

7、00),?1 mol/L?LiPF6/?(EC)?(DMC)(EC:DMC=1:1).?,?17 mAh/g(0.1 C),?2.04.3 V.2?1?,LiFePO4?,?,?.?,?,?.EDS?,?LiFePO4?.?,?LiFePO4?.?LiFePO4?,?.?,?LiFePO4?.?,?LiFePO4?,?.?,?,?,?.?1LiFePO4?PyC/LiFePO4(?26min)?CNF/LiFePO4(?36 min)?SEM?Fig.1 SEMimagesoftherawLiFePO4(a),PyC/LiFePO4with 26 min reaction time(b)and

8、 CNF/LiFePO4with 36 min reaction time(c)24?23?24?23?24?23?,?,?(?2).?,?,?.?,?,?LiFePO4?.?:?15,?;?,?,?.?550?,?,?,?.?,?,?.XRD?,?LiFePO4?.?d002?,?2?/?Fig.2 Relationship between reaction time and con-tent of PyC/CNF?3LiFePO4?26 min PyC/LiFePO4?36 min CNF/LiFePO4?XRD?Fig.3 XRD patterns of raw LiFePO4,PyC/

9、LiFePO4with 26 min reaction time and CNF/LiFePO4with 30 min reaction time?(?3).?,?R?(?D?G?,?16)?2.0,?R?2.6,?,?.?,LiFePO4?4060 nm,?,?,?0.340.36 nm(?4),?XRD?.LiFePO4?CNF?,?(?5).LiFePO4?1.52104m,?3.8%?,?5?,?,?,?13%?,?7?.CNF/LiFePO4?PyC/LiFePO4?,?,?,?LiFePO4?.LiFePO4?17,?LiFePO4?8.6%?,PyC/?4LiFePO4?HRTE

10、M?Fig.4 HRTEMimageoftheCNFgrowingonLiFePO4?5?Fig.5 Relationship of resistivity and PyC or CNFcontent1?:?251?:?251?:?25?6LiFePO4?PyC/LiFePO4?CNF/LiFePO4?Fig.6 Charge capacities of LiFePO4,PyC/LiFePO4and CNF/LiFePO4with cyclingLiFePO4?9.6 mAh/g?146 mAh/g,?12.7%?,?147.2 mAh/g,?8.6%?.?,?3.8%?12.7%?,?8.6

11、%?,50?60%.?,?.?,Li+?18.?,?,?.?,?.?37.6%?,?9.6 mAh/g?163.9 mAh/g.?12.3%?,60?60%?,?.?20.8%?,100?95%?,?,?.?LiFePO4?PyC/LiFePO4?CNF/LiFePO4?,?,?,?LiFePO4?,?,?9,10.?LiFePO4?,?PyC/LiFePO4?.?,?LiFePO4?,?,?19,20;?,LiFePO4?,?.?,?.?,?8.6%?,?.?,?18,21,?.?LiFePO4?.?LiFePO4?LiFePO4?,?,?.?,?,?LiFePO4?,?,?,?,?(?).

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