Characterization of electrode/electrolyte interface with X-ray reflectometry and epitaxial-film LiMnO electrode
LiMnO薄膜電極/溶液界面のX線反射率測定による構造解析
平山 雅章*; 園山 範之*; 伊藤 真純*; 箕浦 真知子*; 森 大輔*; 山田 淳夫*; 田村 和久 ; 水木 純一郎; 菅野 了次*
Hirayama, Masaaki*; Sonoyama, Noriyuki*; Ito, Masumi*; Minoura, Machiko*; Mori, Daisuke*; Yamada, Atsuo*; Tamura, Kazuhisa; Mizuki, Junichiro; Kanno, Ryoji*
面方位を制御してSrTiO上に作成したLiMnO薄膜電極を用い、リチウムイオン電池電極/溶液界面の構造をX線反射率により検討した。ex situでの実験では、電極表面に不純物層が堆積しており、この電極を溶液に浸漬するとこの不純物層は溶解することが明らかになった。その場測定を行った結果、反応性が薄膜の面方位に依存していることが明らかになった。
Structural changes at electrode/electrolyte interface of a lithium cell were studied by X-ray reflectometry and two-dimensional model electrodes with a restricted lattice plane of LiMnO. The ex situ reflectometry indicated that a thin impurity layer covered the lattice plane of the as-grown film. The impurity layer was dissolved and a solid-electrolyte-interface-like phase appeared after the electrode was soaked into the electrolyte. The in situ observation clarified that the surface reactivity depended on the lattice planes of the spinel; the defect layer at the (111) plane was stable during the electrochemical reaction, whereas a slight decrease in the film thickness was observed for the (110) plane. Our surface characterization of the intercalation electrode indicated that the surface structure changes during the pristine stage of the change-discharge processes and these changes are dependent on the lattice orientation of LiMnO.