Formation of carbon-coated ZnFe2O4 nanowires and their highly reversible lithium storage properties

In this paper, carbon-decorated ZnFe2O4 nanowires, having one-dimensional geometry with diameters of 70-150 nm and lengths of several micrometers, were prepared and used as a highly reversible lithium ion anode material. They can be obtained from calcination of glucose-coated ZnFe2(C2O4)(3) nanowires, which were prepared in glucose containing microemulsion solutions. The physicochemical properties of carbon-coated ZnFe2O4 nanowires were investigated by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The carbon-coated ZnFe2O4 nanowires showed a substantially increased discharge capacity of ca. 1285.1 mA h g(-1) at the first cycle as compared with non-carbon-coated ZnFe2O4 nanowires (ca. 1024.3 mA h g(-1)) and ZnFe2O4 nanoparticles (ca. 1148.7 mA h g(-1)). Moreover, the discharge capacity of the carbon-coated ZnFe2O4 nanowires was maintained with no degradation even after 100 charge/discharge cycles. The high cycling durability, rate capability, and coulombic efficiency suggest that the carbon-coated ZnFe2O4 nanowires prepared here can be promising anode candidates for a highly reversible lithiumstorage electrode.