Morphology and electrical properties of Li₂FeSiO₄/C prepared by a vacuum solid-state reaction

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• 作者：Kun Gao ; Juan Zhang ; Shu-Dan Li ; ^{lishudan0451@163.com}
• 关键词：Composite materials ; Oxides ; Heat treatment ; Phase transitions
• 刊名：Materials Chemistry and Physics
• 出版年：2013
• 出版时间：15 May, 2013
• 年：2013
• 卷：139
• 期：2-3
• 页码：550-556
• 全文大小：1155 K

文摘

To improve the electrochemical performance of Li₂FeSiO₄ with low electric conductivity, the Li₂FeSiO₄/C composites with different carbon content are synthesized by a vacuum solid-state method. The experimental results show that the introduced carbon decrease the crystallite sizes of final products, but still keep the serious aggregated particles and make the Li₂SiO₃ impurity further increased. The Li₂FeSiO₄ with 4.15?wt. % carbon delivers the initial discharge capacity of 108.9?mAhg^?1 at room temperature and?retains 71.5 % of the initial discharge capacity after 50 cycles. The transition phenomenon in charge-discharge curves and the variation in D_Li+ values with the cycling number clearly indicate a transient process of phase transition for Li₂FeSiO₄, which requires at least 5-10 charge-discharge cycles.