Synthesis of α-Fe2O3nanoparticles from Fe(OH)3 sol and their composite with reduced graphene oxide for lithium ion batteries

Abstract

α-Fe₂O₃/reduced graphene oxide (α-Fe₂O₃/RGO) composite has been synthesized by a facile hydrothermal method. Fe(OH)₃ sol is creatively employed as the precursor and no nucleating agent is employed to help Fe³⁺ change to Fe(OH)₃. In the hydrothermal process, Fe(OH)₃ sol transforms to α-Fe₂O₃ particles and GO becomes RGO with hydrazine hydrate. Composites with different ratios between α-Fe₂O₃ and RGO for comparison are investigated as anode LIB materials. Among the composites, the α-Fe₂O₃/RGO containing 73% α-Fe₂O₃ exhibits the highest reversible specific capacity of ∼950 mA h g⁻¹ after 70 cycles at a current density of 100 mA g⁻¹. When the current density is 800 mA g⁻¹, the capacity still remains as ∼700 mA h g⁻¹, showing superior rate capability. The significant electrochemical property improvements of α-Fe₂O₃/RGO can be attributed to the uniform α-Fe₂O₃ nanoparticles (20–30 nm) and the RGO substrate, which provides high electrical conductivity and stability.