Synthesis of LiFePO₄/C nanocomposites by a novel process and their electrochemical properties

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• 作者：Izumi Taniguchi ; ^{taniguchi.i.aa@m.titech.ac.jp} ; Renat Tussupbayev
• 关键词：Emulsion drip combustion ; Fluidized bed ; Lithium iron phosphate ; Cathode ; Lithium-ion batteries
• 刊名：Chemical Engineering Journal
• 出版年：2012
• 期刊代码：16_13858947
• 类别：ce
• 出版时间：1 June, 2012
• 卷：192
• 期：Complete
• 页码：334-342
• 文件大小：2276 K

摘要

LiFePO₄/C composites were successfully prepared by emulsion drip combustion in a fluidized bed reactor followed by heat treatment from the precursor solution; LiNO₃, Fe(NO₃)₃路9H₂O and H₃PO₄ were stoichiometrically dissolved in distilled water. The ordered LiFePO₄ olivine structure could be obtained after the heat treatment of the as-prepared samples was performed at temperature ranges from 500 to 800 掳C in N₂ + 3%H₂ atmosphere. It was also confirmed from the transmission electron microscopy (TEM) observation with electron diffraction spectrometry (EDS) that the final samples were LiFePO₄/C composites with larger secondary particles. The LiFePO₄/C composites were prepared at 600 掳C and then annealed at 700 掳C exhibited a first discharge capacity of 93 mAh g^鈭? at a 0.1 C rate, which corresponded to 55%of the theoretical capacity.

The as-prepared sample at 600 掳C by the emulsion drip combustion was milled in ethanol by a planetary ball-milling and then annealed at 700 掳C for 4 h in N₂ + 3%H₂ atmosphere. It was clearly seen from scanning electron microscopy(SEM) and TEM images with EDS that the final sample was made up of agglomerates with approximately 100 nm primary particles covered with a thin carbon layer. As a result, LiFePO₄/C nanocomposites could be successfully prepared by a combination of emulsion drip combustion and wet ball-milling followed by heat treatment. The LiFePO₄/C nanocomposites delivered a first discharge capacity of 147 mAh g^鈭? (86%of theoretical capacity) at a 0.1 C rate. The capacity retention after 100 cycles for the cell was 98%at a 1 C rate.