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Li 2 NbO 3 –Li 2 MnO 3 Pseudo‐Binary Compounds Crystallizing into Distorted Rocksalt Structures
Author(s) -
Matsunaga Toshiyuki,
Shimoda Keiji,
Okazaki Kenichi,
Ishikawa Yoshihisa,
Yonemura Masao,
Ukyo Yoshio,
Fukunaga Toshiharu,
Matsubara Eiichiro
Publication year - 2019
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201900003
Subject(s) - monoclinic crystal system , crystallography , type (biology) , crystal structure , neutron diffraction , octahedron , materials science , metal , crystallization , natural bond orbital , chemistry , density functional theory , computational chemistry , ecology , organic chemistry , metallurgy , biology
Li 2 (Nb x Mn 1– x )O 3 is one of the Li‐rich, Mn‐based cathode materials represented by the structural prototype Li 2 MnO 3 . Many of these cathode materials crystallize into monoclinic structures; however, our neutron and X‐ray structural analyses revealed that the Li 2 (Nb x Mn 1 –x )O 3 compounds adopt NaCl‐type cubic structures in a wide compositional range, at least between x = 5 at.% and x = 50 at.%. In these NaCl‐type structures, Na sites are randomly occupied by the three kinds of metal cations and the Cl sites are solely occupied by O 2− anions. These cubic crystals comprise distorted atomic arrangements that are randomly displaced from the atomic positions in a regular NaCl‐type structure. Density functional theory calculations based on these distorted NaCl‐type structure models indicate lower total energy than those of the corresponding monoclinic structures. This result demonstrates that the Li 2 (Nb x Mn 1– x )O 3 compounds can crystallize into such NaCl‐type structures to decrease the crystallization energy.