Structure refinement of the spinel-related phases Li2Mn2O4 and Li0.2Mn2O4

The crystal structures of the lithium-rich and lithium-deficient spinel phases Li₂[Mn₂]O₄ and Li_0.2[Mn₂]O₄ have been determined by neutron-diffraction techniques. Structure refinements confirm earlier reports that the [Mn₂]O₄ framework of the Li[Mn₂]O₄ spinel remains intact during both lithium insertion and extraction, but demonstrate unequivocally that in Li₂[Mn₂]O₄ the Li⁺ ions reside in face-shared tetrahedra and octahedra of the cubic-close-packed oxygen-anion array; in Li_0.2[Mn₂]O₄ the Li⁺ ions are located randomly on only the tetrahedral sites of the spinel structure.