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

Abstract Mesoporous Fe 2 O 3 spherical particles with amorphous or crystalline structure were prepared at different temperatures using aerosol spray pyrolysis. The crystalline Fe 2 O 3 (C-Fe 2 O 3 ) anodes pyrolysized at 800 °C show better electrochemical performance than the amorphous Fe 2 O 3 (A-Fe 2 O 3 ) pyrolysized at 600 °C. Both, however, changed into nano-crystallite porous structure after charge/discharge cycles. The C-Fe 2 O 3 spherical particles provided high reversible capacity of 800 mAh/g at 0.5 C over 300 charge/discharge cycles and retained 300 mAh/g at 10 C. The excellent cycling stability of the C-Fe 2 O 3 spherical particles is mainly attributed to the interior voids in the mesoporous Fe 2 O 3 particles that provide extra space to accommodate volume change and alleviate structural strain/stress during electrochemical reaction. The high rate performance of mesoporous Fe 2 O 3 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.