Synthesis, Crystal Structure, and Magnetic Property of Delithiated LixMnO2 (x < 0.1) Single Crystals: A Novel Disordered Rocksalt-Type Manganese Dioxide

Single crystals of the chemically and electrochemically delithiated Li x MnO 2 ( x < 0.1) have been successfully synthesized from the parent orthorhombic LiMnO 2 single crystals. A single-crystal X-ray diffraction study revealed that the average structure of Li x MnO 2 was the disordered rocksalt-type with the space group Fm 3̄ m, and the lattice parameter a = 4.095(3) Å. Some additional spots indicating the superlattice structure and diffuse scattering could be observed in the X-ray precession photographs. The mechanism of the structural transformation from the parent orthorhombic LiMnO 2 to the delithiated cubic Li x MnO 2 was well explained by the manganese ion migration accompanied with Li + extraction. The magnetic properties of the chemically delithiated Li x MnO 2 are compared with those of the parent LiMnO 2 . The extracted Curie constant in Li x MnO 2 is consistent with the residual lithium content found analytically, as in the case of λ-MnO 2 .