Single-crystalline alpha-Fe2O3 void@frame microframes for rechargeable batteries

It is still a challenging task to prepare single crystalline void@frame hollow-open microframes, although single crystalline void@shell hollow structures have been reported. Herein, single-crystalline alpha-Fe2O3 microframes with void@frame open structures and perforated shells are prepared through a template-free calcination method via a discontinuous grain growth mechanism. The single-crystalline alpha-Fe2O3 void@frame microframes demonstrated excellent electrochemical performance in terms of specific capacity, cycle life and high rate as negative electrode materials for lithium ion batteries, in contrast to solid microparticles. Additionally, their potential application as negative electrode materials for sodium ion batteries has been demonstrated.