In-situ scanning electron microscopy observations of Li plating and stripping reactions at the lithium phosphorus oxynitride glass electrolyte/Cu interface

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• 作者：Fumihiro Sagane^a ; Ryosuke Shimokawa^a ; Hikaru Sano^b ; ^c ; Hikari Sakaebe^b ; ^c ; Yasutoshi Iriyama^b ; ^d ; ^{iriyama@numse.nagoya-u.ac.jp}
• 关键词：Lithium ; Anode ; All-solid-state battery ; In-situ SEM ; Interface
• 刊名：Journal of Power Sources
• 出版年：2013
• 出版时间：1 March, 2013
• 年：2013
• 卷：225
• 期：Complete
• 页码：245-250
• 全文大小：1415 K

文摘

Morphology variations during electrochemical lithium plating-stripping reactions at the lithium phosphorus oxynitride glass electrolyte (LiPON)/copper current collector (Cu) interface are observed in-situ by scanning electron microscopy (SEM). This in-situ SEM observation shows dynamically that the plating reactions at 50?¦ÌA?cm^?2 distribute initial lithium growth sites sparsely at the LiPON/Cu interface, later, local lithium growth occurs from the pre-plated sites through the Cu film, and finally, most of the precipitated lithium grows to be needle-shape with the height of micron order. This local growth rate attains to be 6.8?mA?cm^?2, about 100 times higher value than applied one. When those precipitated lithium are stripped at 50?¦ÌA?cm^?2, core region of each precipitate is mostly stripped but its degree depends on the length of the precipitate. This dependency will arise from the diffusivity of Li. When this stripping current density is increased to 500?¦ÌA?cm^?2, the coulomb efficiency is further decreased. In-situ SEM observation shows that plated lithium around the interface becomes thin preferentially while that far away from the interface (upper side of plated lithium) remains unchanged. This will isolate most of precipitate lithium from LiPON film electrically, leading to further decreasing of the coulomb efficiency.