LAUSR

Abstract Core-shell olivine-type electrospun and doped LiFePO4/FeS/C composite fibers were synthesized via a single-step process employing an electrospinning method using LiOH·H2O, metal sul phates, H3PO4, citric acid, and polyvinylpyrrolidone (PVP) as the starting materials. Electron microscopy studies showed that the mean diameter of the core-shell composite fibers was about 280 ± 20 nm with a LiFePO4 phase forming a core with a diameter of about 100 ± 20 nm and a carbon shell with a thickness of 80 ± 20 nm. An FeS phase was formed by a direct reduction of iron (II) sulfate (FeSO4) that was evenly distributed within the core region of the composite fibers and further improved the electronic conductivity of the fibers. Na1+, Mg2+, and Al3+ doping ions affected fiber morphology and electrochemical performance. All composite fibers showed excellent electrochemical performance. However, Al3+ ions improved the electrochemical performance of the composite fibers to a significantly greater degree than Na1+ and Mg2+ doping ions, increasing the electronic and ionic conductivities of the material while maintaining their core-shell composite fiber characteristics.