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Journal of Electrochemistry ›› 2016, Vol. 22 ›› Issue (5): 521-527.doi: 10.13208/j.electrochem.160541

• Special Issue on Energy Electrochemical Materials(Guest Editor: Professor Jun Chen) • Previous Articles     Next Articles

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*   

  1. 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:2016-05-03 Revised:2016-05-19 Online:2016-10-28 Published:2016-07-28
  • Contact: LIU Yong-feng E-mail:mselyf@zju.edu.cn


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.

Key words: lithium-ion batteries, anode materials, Li-Si alloys, electrochemical properties, lithium storage mechanism

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