Superior electrochemical performance and structure evolution of mesoporous Fe2O3 anodes for lithium-ion batteries

Abstract

Mesoporous Fe2O3 spherical particles with amorphous or crystalline structure were prepared at different temperatures using aerosol spray pyrolysis. The crystalline Fe2O3 (C-Fe2O3) anodes pyrolysized at 800°C show better electrochemical performance than the amorphous Fe2O3 (A-Fe2O3) pyrolysized at 600°C. Both, however, changed into nano-crystallite porous structure after charge/discharge cycles. The C-Fe2O3 spherical particles provided high reversible capacity of 800mAh/g at 0.5C over 300 charge/discharge cycles and retained 300mAh/g at 10C. The excellent cycling stability of the C-Fe2O3 spherical particles is mainly attributed to the interior voids in the mesoporous Fe2O3 particles that provide extra space to accommodate volume change and alleviate structural strain/stress during electrochemical reaction. The high rate performance of mesoporous Fe2O3 is attributed to (1) fast charge transfer reaction at the large interfacial area between electrode and liquid electrolyte, and (2) the reduced Li-ion diffusion distances. This study not only provides a simple synthesis method for lithium ion batteries, but also helps in designing novel and high performance electrode materials.