1-D nanostructure comprising porous Fe2O3/Se composite nanorods with numerous nanovoids, and their electrochemical properties for use in lithium-ion batteries

Abstract

Novel 1-D nanostructures composed of porous Fe2O3/Se composite or subsequently formed hollow Fe2O3 nanorods were introduced. Carbon nanofibers embedded with FeSe2 needle-like nanorods were prepared via the selenization of electrospun nanofibers. During the oxidation process, the faster diffusion rate of Fe ions (76 pm in size) relative to that of the Se ions (184 pm in size) resulted in nanoscale Kirkendall diffusion mechanism, thus forming the 1-D nanostructure comprising nanorods composed of Se/voids/Fe2O3 as an intermediate. The complete conversion of FeSe2 into Fe2O3 and the combustion of C, which caused necking between the nanorods, resulted in a 1-D nanoarchitecture composed of hollow Fe2O3 nanorods. The discharge capacity during the 400th cycle of the 1-D nanostructures comprising Fe2O3/Se composite nanorods was 1456 mA h g(-1) at a current density of 1.0 A g(-1). The high structural stability of this unique architecture during repeated lithium insertion/deinsertion processes resulted in superior lithium-ion storage performance.