Porous hollow α-Fe2O3@TiO2 core-shell nanospheres for superior lithium/sodium storage capability

Porous hollow alpha-Fe2O3@TiO2 core-shell nanospheres for use as anode materials in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) have been successfully fabricated by a simple template-assisted method, which has been rarely reported before. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N-2 adsorption-desorption isotherms reveal that the as-prepared alpha-Fe2O3@TiO2 is composed of a hollow inner cavity and an outer shell with massive mesopores. This porous hollow structure is capable of buffering the large volume variation of alpha-Fe2O3 during cycling and preventing the electrode from pulverization and aggregation, as well as providing sufficiently large interstitial space within the crystallographic structure to host alkalis (Li and Na). As a consequence, this hybrid composite exhibits outstanding electrochemical properties, e.g., high specific capacity, excellent cyclability, satisfactory rate performance, and splendid initial coulombic efficiency for both LIBs and SIBs.