Synthesis and structures of lithium manganese oxide spinel, LiMn2O4−δ (0≤δ≤0.27)

Lithium manganese oxides spinels were synthesized under various synthesis conditions and their structures were determined by TOF neutron powder diffraction measurements. Oxygen vacancies exist for the samples synthesized above 800°C, and the amount of vacancies was found to be sensitive to the synthesis conditions. The nearly stoichiometric spinels were synthesized at 750°C in O2 followed by heating at 470°C. The transition temperatures of the cubic–orthorhombic transitions and the magnetic properties varied with the compositions. The stoichiometric spinel showed no cubic–orthorhombic phase transition.