Effect of copper doping on LiMnPO4 prepared via hydrothermal route

Fine-sized, well-crystallized LiMnPO4 and two Cu-doped derivatives (2% and 5% Cu2+ doping) are readily prepared via a hydrothermal route. X-ray diffraction (XRD) combined with structural analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area analysis, and galvanostatic charge-discharge tests are applied to characterize these materials. The structure analysis shows that only a negligible amount of Cu2+ ions (0.2%) occupy the Li sites in the 2% Cu-doped material, while a considerable amount of Cu2+ ions (1.8%) occupy the Li sites in the 5% Cu-doped one. The electrochemical tests show that the 2% Cu-doped LiMnPO4 displays an improved electrochemical performance compared with the undoped LiMnPO4, while the 5% Cu-doped LiMnPO4 exhibits a decreased activity.