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能源电化学材料近期研究专辑(南开大学 陈军教授)

晶态Li12Si7锂离子电池负极材料的电化学性能研究

  • 杨亚雄 ,
  • 马瑞军 ,
  • 高明霞 ,
  • 潘洪革 ,
  • 刘永锋
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  • 硅材料国家重点实验室,浙江省电池新材料及应用技术重点实验室,浙江大学材料科学与工程学院,浙江杭州 310027

收稿日期: 2016-05-03

  修回日期: 2016-05-19

  网络出版日期: 2016-07-28

基金资助

国家自然科学基金资助项目(51471152),教育部创新团队项目(IRT13037)和中组部拔尖人才支持

Electrochemical Performance of Crystalline Li12Si7 as Anode Material for Lithium Ion Battery

  • YANG Ya-xiong ,
  • MA Rui-jun ,
  • GAO Ming-xia ,
  • PAN Hong-ge ,
  • LIU Yong-feng
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  • State Key Laboratory of Silicon Materials, Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China

Received date: 2016-05-03

  Revised date: 2016-05-19

  Online published: 2016-07-28

摘要

通过加热摩尔比为12:7的LiH/Si球磨混合物,避免了Li与Si之间巨大的熔点差异,成功制备了晶态Li12Si7合金,研究了其电化学性能和储锂机制. 发现Li12Si7在0.02 ~ 0.6 V的嵌脱锂过程中,只发生晶胞体积的变化,而不产生相变,呈现出明显的固溶储锂机制. 该固溶储锂机制的存在,有效抑制了Si基负极材料嵌脱锂过程中由于相变导致的体积效应,使得晶态Li12Si7在0.02 ~ 0.6 V电压范围内具有显著改善的电化学性能,其首次库伦效率高达100%,30次循环后的可逆容量保持率约为74%,分别优于相同条件下原始Si电极的55%和37%.

本文引用格式

杨亚雄 , 马瑞军 , 高明霞 , 潘洪革 , 刘永锋 . 晶态Li12Si7锂离子电池负极材料的电化学性能研究[J]. 电化学, 2016 , 22(5) : 521 -527 . DOI: 10.13208/j.electrochem.160541

Abstract

Crystalline Li12Si7 is successfully synthesized by heating the mixture of LiH and Si with a molar ratio of 12:7, which avoids the huge difference of the melting points between Li and Si. The electrochemical performance and lithium storage mechanism of the as-prepared Li12Si7 are studied in this work. It is found that only a change in cell volume takes place without a phase change during the lithiation/delithiation of Li12Si7 at a voltage range of 0.02 ~ 0.6 V, exhibiting a solid-solution lithium storage mechanism. Such a lithium storage process effectively retards the volume effect caused by the phase change during lithiation/delithiation of Si-based anode. This induces significantly the improved electrochemical properties of crystalline Li12Si7 while cycling at 0.02 ~ 0.6 V. The first Coulombic efficiency of crystalline Li12Si7 is determined to be as high as 100%, and the capacity retention is 74% after 30 cycles, which are distinctly higher than those of Si anode (55% and 37%, respectively) under identical conditions.

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