Phase relations of Li2O–FeO–SiO2 ternary system and electrochemical properties of Li x Si y O z compounds

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• 作者：Danlin Yan ; Xiaofeng Geng ; Yanming Zhao ; Xinghao Lin…
• 刊名：Journal of Materials Science
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：51
• 期：13
• 页码：6452-6463
• 全文大小：3,703 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Materials Science
  Characterization and Evaluation Materials
  Polymer Sciences
  Continuum Mechanics and Mechanics of Materials
  Crystallography
  Mechanics
  
• 出版者：Springer Netherlands
• ISSN：1573-4803
• 卷排序：51

文摘

Phase equilibria in the ternary Li₂O–FeO–SiO₂ system have been studied by means of X-ray powder diffraction. The experimental results show that no new lithium ferrous silicate compounds can be found in our experimental condition which may be a candidate cathode material for LIBs. The Li₂O–FeO–SiO₂ system can be characterized by the existence of 9 three-phase regions. In Li₂O–SiO₂ binary system, Li₂SiO₃ and Li₄SiO₄ are purely synthesized by solid-state reactions; other new information includes the electrochemical properties of Li₂SiO₃ and Li₄SiO₄ compounds, where the electrochemical test indicated that initial discharge-specific capacities can reach to 136 and 129 mAhg−1, respectively. Enhanced performance was exhibited after carbon coating. The initial discharge-specific capacities of carbon-coated Li₂SiO₃ and carbon-coated Li₄SiO₄ compound can reach to 230 and 220 mAhg−1 respectively. Our results show that Li₂SiO₃ and Li₄SiO₄ samples have better capacity retention except for the first discharge. No significant change can be seen in ex situ XRD patterns for Li₂SiO₃/C, while the lithium-ion insertion/extraction reaction may exist in Li₄SiO₄/C as forming solid solutions (nominated Li_4+xSiO₄).