Li conduction pathway in cathode material, LiMnO, for Li ion battery studied by neutron diffraction method

中性子回折法によるLiイオン二次電池正極材LiMnOのLi伝導経路解析

井川 直樹   ; 樹神 克明   ; 田口 富嗣; 美留町 厚; 社本 真一  

Igawa, Naoki; Kodama, Katsuaki; Taguchi, Tomitsugu; Birumachi, Atsushi; Shamoto, Shinichi

Liイオン二次電池正極材として利用されるLiMnOの結晶構造とLiイオン伝導経路を解析するため中性子回折実験を行った。本材料の結晶構造は、格子定数=8.2422(3) 、空間群-3で最適化でき、Li, Mn及びOは各々単位胞中の8, 16, 32サイトを占めた。最大エントロピー法解析の結果、Liの拡散経路は8, 16, 8サイトを結ぶ広がりとして観察された。

The crystal structure of LiMnO was analyzed by the Rietveld method using the neutron powder diffraction. The neutron scattering length density map was also analyzed to investigate the Li conduction path by the maximum entropy method. The crystal structure was refined with the space group, -3(origin choice 2) with a lattice constant, = 8.2442(3) at room temperature. Li, Mn and O atoms occupied 8, 16 and 32 sites, respectively. The cation mixing at Li and other metal sites was not observed. The neutron scattering length density map exhibits 3-dimensional Li conduction pathway clearly, indicating the Li through the 8-16-8 sites.