Synthesis of mixed-conducting carbon coated porous γ-Fe ₂O₃ microparticles and their properties for reversible lithium ion storage

Disk-like α-Fe₂O₃ microparticles were synthesized by a facile hydrothermal method and transformed into iron oxide/carbon composites by chemical vapor deposition in an acetylene atmosphere. Through careful control of the reaction time, carbon-coated porous γ-Fe₂O₃ microparticles with reversible Li ⁺ storage properties were produced. The measured specific capacity after 40 cycles of charge and discharge was in excess of 900 mA h g^-1 and rate capability was very good up to a current density of 2000 mA g ^-1. The good performance in Li⁺ storage could be attributed to the combination of porosity and a uniform nanocarbon coating which provided mixed-conducting properties for the fast diffusion of both lithium ions and electrons.