One-Pot Microwave-Hydrothermal Synthesis and Characterization of Carbon-Coated LiMPO[sub 4] (M=Mn, Fe, and Co) Cathodes

Olivine ( , Fe, and Co) cathodes with a thin layer of carbon coating have been prepared by a rapid, one-pot, microwave-assisted hydrothermal process within a short reaction time at temperatures as low as . The carbon coating is achieved by an in situ hydrothermal carbonization of glucose during the synthesis process. The resulting nanocomposites are characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy (TEM) before and after heating at for in a flowing argon atmosphere. Although both and prepared under acidic conditions exhibit nanosize rods, prepared under basic conditions display micron-size cubes. The uniform nanocarbon coating achieved as indicated by the TEM data enhances the electronic conductivity and leads to excellent electrochemical performance for in lithium cells. In contrast, both and exhibit inferior electrochemical performances even after carbon coating due to, respectively, the significantly low electronic conductivity and the lack of compatible electrolyte.