論文

査読有り
2018年4月

Prevention of redox shuttle using electropolymerized polypyrrole film in a lithium-oxygen battery

APL Materials
  • Togasaki, Norihiro
  • ,
  • Shibamura, Ryuji
  • ,
  • Naruse, Takuya
  • ,
  • Momma, Toshiyuki
  • ,
  • Momma, Toshiyuki
  • ,
  • Osaka, Tetsuya
  • ,
  • Osaka, Tetsuya

6
4
開始ページ
047704
終了ページ
047711
記述言語
英語
掲載種別
DOI
10.1063/1.5011135

© 2018 Author(s). Among the recent advancements in lithium-oxygen (Li-O 2 ) chemistries, redox mediators (RMs) have been revealed to play a significant role in decreasing overpotential on charging and in improving cycling performance. However, an intrinsic problem is redox shuttle of RMs, which leads to degraded RM utilization and induces the accumulation of discharge products on the cathode surface; this remains a significant issue in the current battery cell configuration (Li anode/separator/cathode). To address this detrimental problem, herein we propose a novel Li-O 2 cell incorporating a freestanding electropolymerized polypyrrole (PPy) film for the restriction of the redox-shuttle phenomenon of lithium iodide (Li anode/separator/PPy film/cathode). In this study, a PPy film, which is prepared through oxidative electropolymerization using an ionic liquid of 1-methyl-1-butylpyrrolidinium mixed with pyrrole and lithium bis(trifluoromethanesulfonyl)imide, is introduced between the cathode and the separator. From the charge-discharge voltage profile, it is confirmed that the PPy film suppresses the diffusion of the oxidized I 3 - to the Li anode, while allowing Li ion transport. Secondary scanning electron microscope measurements confirm that the chemical reactions between I 3 - and Li 2 O 2 are facilitated by the presence of the PPy film because I 3 - remains near the cathode surface during the charging process. As a result, the cycling performance in the Li-O 2 cells with PPy film exhibits a cycling life four times as long as that of the Li-O 2 cells without PPy film.

リンク情報
DOI
https://doi.org/10.1063/1.5011135