2025-10-28 北陸先端科学技術大学院大学,東京科学大学
Web要約 の発言：
図1（a）[100]方位から見た層状LiCoO2の結晶構造モデル。（b）走査ナノビーム電子回折の模式図。（c）実験と（d）計算の電子回折図形。（e）実験と（f）計算のケプストラム。中心以外の明るいスポットが結晶構造に由来します。（g）結晶構造の合成マップ。青、緑、赤色が強いほど、層状、岩塩、スピネル構造であることを示します。
＜関連情報＞
- https://www.jaist.ac.jp/whatsnew/press/2025/10/28-2.html
- https://pubs.acs.org/doi/10.1021/acs.nanolett.5c03692
走査ナノビーム電子回折のケプストラムマッチングによるエピタキシャルカソードの結晶相の低線量ナノスケール可視化 Low-Dose Nanoscale Visualization of Crystal Phases in Epitaxial Cathodes via Cepstral Matching of Scanning Nanobeam Electron Diffraction
Kohei Aso,Takafumi Kakeya,Takumu Tsuchida,Hiroki Ito,Sho Asano,Kenta Watanabe,Kazutaka Mitsuishi,Koji Kimoto,Keisuke Shinoda,Takuya Masuda,Masaaki Hirayama,and Yoshifumi Oshima
Nano Letters Published: October 21, 2025
DOI:https://doi.org/10.1021/acs.nanolett.5c03692
Abstract
Layered cathodes are essential for achieving a high energy density in rechargeable lithium-ion batteries, but they suffer from capacity fade due to local crystal phase transitions during charge–discharge cycles. Understanding these phase transitions is essential to minimizing their effects, but their nanometer size and sensitivity to experimental conditions make observation difficult. Here, we visualized nanometer-scale crystal phases within an epitaxial LiCoO2 cathode after 100 charge–discharge cycles by matching experimental and simulated cepstra derived from scanning nanobeam electron diffraction. While the LiCoO2 bulk remained a layered structure, spinel- and rocksalt-type phases were observed within 3 nm of the cathode–electrolyte interface. The developed method achieved a spatial resolution of 1.5 nm across a field of view of several hundred nanometers with minimal electron beam damage. The cepstral matching analysis offers valuable insights into the interfacial phase transitions and will aid in the design of high-performance lithium-ion batteries.
