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 LixMnO2 (x < 0.1) have been successfully synthesized from the parent orthorhombic LiMnO2 single crystals. A single-crystal X-ray diffraction study revealed that the average structure of LixMnO2 was the disordered rocksalt-type with the space group Fm (3) over barm, and the lattice parameter a = 4.095(3) Angstrom. 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 LiMnO2 to the delithiated cubic LixMnO2 was well explained by the manganese ion migration accompanied with Li+ extraction. The magnetic properties of the chemically delithiated LixMnO2 are compared with those of the parent LiMnO2. The extracted Curie constant in LixMnO2 is consistent with the residual lithium content found analytically, as in the case of lambda-MnO2.