插层(化学)
石墨
六氟磷酸盐
电化学
材料科学
电解质
阴极
电极
体积膨胀
酰亚胺
无机化学
碳纤维
离子液体
化学工程
复合材料
化学
复合数
高分子化学
有机化学
物理化学
催化作用
医学
内科学
工程类
作者
Jessica Huesker,Martin Winter,Tobias Placke
出处
期刊:ECS transactions
[The Electrochemical Society]
日期:2015-12-08
卷期号:69 (22): 9-21
被引量:33
标识
DOI:10.1149/06922.0009ecst
摘要
Anion intercalation into graphitic carbons typically occurs at high cathode potentials, i.e., above 4.5 V vs. Li/Li + , and is accompanied by a gallery height expansion and volume increase. The volume increase by accommodation of guest ions such as hexafluorophosphate (PF 6 - ) or bis(trifluoromethanesulfonyl) imide (TFSI - ) is in the range of 130% to 140% according to a gallery height increase from 3.35 Å for pristine graphite to 7.74 to 7.99 Å for the graphite intercalation compounds. The gallery height expansion upon intercalation/de-intercalation in turn also results in an expansion/shrinkage behavior of the thickness of the composite graphite cathode which thus influences the mechanical integrity of the electrode and therefore the overall cycling stability. Furthermore, the type of polymeric binder will have a strong influence on the mechanical stability of the graphite-based cathodes. In this work, the expansion and shrinkage behavior of graphite positive electrodes related to PF 6 - and TFSI - anion intercalation/de-intercalation into/from graphite was studied with electrochemical dilatometry technique. In particular, the reversibility of the expansion behavior as well as the maximum electrode thickness for the different anions/electrolytes is studied.
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