LiMn0.7Fe0.3PO4 nanorods grown on graphene sheets synthesized in situ by modified microwave-assisted solvothermal method as high-performance cathode materials

Abstract

Nanosized hybrid cathode materials, LiMn0.7Fe0.3PO4 with olivine structure anchoring on the graphene matrices, were facilely prepared by employing a modified microwave-assisted solvothermal method. Many measurements such as XRD, SEM, TEM, EDS, Raman spectra and XPS have been utilized to identify their physicochemical properties. Electron microscopy analyses revealed that the widely distributed LiMn0.7Fe0.3PO4 nanorods were selectively and homogeneously grown on graphene sheets with rod length of 100–200 nm and diameter of 30–50 nm. In particular, it was fully improved that the deliberate additions of conductive matrix, graphene oxide, have facilitated the specific growth of LiMn0.7Fe0.3PO4 and therefore improved their homogeneity and morphology to form a huge electric network. Electrochemical assessments indicated that the as-synthesized materials delivered an initial discharge capacity of 159.8 mAh g−1 at 0.1 C and even 81.6 mAh g−1 at 20 C, meanwhile maintained their excellent rate capability and cycling ability, about 91.7% capacity retention after 80 cycles at 1 C. Theoretically speaking, the excellent electrochemical performance maybe makes these nanosized LiMn0.7Fe0.3PO4 cathode materials a potential candidate for the practical implications in high-power devices and energy storage systems.