Low-spinMn3+ion in rhombohedralLiMnO2predicted by first-principles calculations

By means of first-principles calculations using spin-polarized generalized gradient approximation method, the ${\mathrm{Mn}}^{3+}$ ion in hypothetical rhombohedral ${\mathrm{LiMnO}}_{2}$ $(r\text{\ensuremath{-}}{\mathrm{LiMnO}}_{2})$ is predicted to be in an unusual low-spin state, i.e., all of its four $3d$ electrons occupy the three ${t}_{2g}$ levels, which makes $r\text{\ensuremath{-}}{\mathrm{LiMnO}}_{2}$ not only a good cathode material for rechargeable lithium-ion battery, but also a possible half-metal for spintronics. Following the proposed synthesis approaches deduced from the calculations, well crystallized $r\text{\ensuremath{-}}{\mathrm{LiMn}}_{0.65}{\mathrm{Cr}}_{0.35}{\mathrm{O}}_{2}$ is obtained through hydrothermal reaction and the low-spin state of the ${\mathrm{Mn}}^{3+}$ ion is verified by magnetic measurements.