Magnetic order and electronic properties of Li sub(2)Mn sub(2)(MoO sub(4)) sub(3) material for lithium-ion batteries: ESR and magnetic susceptibility studies

We describe the application of electron spin resonance (ESR) and magnetic susceptibility methods to study the magnetic properties and valence state of transition metal ions in Li sub(2)Mn sub(2)(MoO4) sub(3) polyanion compound previously studied for its cathode-active properties in lithium containing batteries. ESR measurements of Li sub(2)Mn sub(2)(MoO sub(4)) sub(3) have shown the presence of Mn super(2+) ions in the octahedral environment of oxygen ions. It is found that the part of manganese ions occupy the anti-site positions in lithium sublattice. The absence of the ESR signal from molybdenum ions indicates that they are non-magnetic and adopt the 6 super(+) valence state. Considerable overlapping between 3d orbitals of transition metal and 2p oxygen orbitals has been experimentally established. This leads to the indirect exchange interaction and antiferromagnetic ordering of manganese ions at 1.4 K.