Applied Surface Science, Vol.463, 322-330, 2019
Enhanced electrochemical performance of alpha-Fe2O3 grains grafted onto TiO2-Carbon nanofibers via a Vapor-Solid reaction as anode materials for Li-Ion batteries
alpha-Fe2O3 grains grafted onto TiO2/carbon nanofibers (CNFs) for use as anode materials in lithium-ion batteries have been successfully fabricated by electrospinning and vapor-solid reaction (VSR). Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N-2 adsorption-desorption isotherms reveal that the ultrafine alpha-Fe2O3 nanoparticles were formed on the TiO2/CNFs and have uniform dispersion along the fiber direction. The VSR approach could retard nucleation, thus making TiO2/CNFs with small Fe2O3 grains grafting (approximately 5 nm in diameter). The TiO2/CNFs are capable of buffering the large volume variation of alpha-Fe2O3 during cycling and preventing electrode pulverization and aggregation, as well as providing sufficiently large interstitial space within the crystallographic structure to host Li ions. The electrochemical properties of the composite electrodes were tested by galvanostatic cycling at both constant and variable current rates. The composite delivers both good rate capability under an uprated current density of 1000 mA g(-1) and especially enhanced cycle stability (similar to 600 mA h g(-1) after 200 cycles at a current density of 1000 mA g(-1)). The super electrochemical performance is attributed to a synergetic effect between alpha-Fe2O3 and TiO2-CNFs as well as the three-dimensional (3D) network, which contributes to greatly enhanced diffusion kinetics and structural stability for lithium-ion batteries. This VSR approach can be extended to other hierarchical metal oxide nanostructures for favorable applications in electrochemical devices.