Three dimensionals α-Fe2O3/polypyrrole (Ppy) nanoarray as anode for micro lithium ion batteries

► Self-supported 3D α-Fe2O3/Ppy electrode was successfully fabricated by a simple method. ► High reversible areal capacity, excellent cyclability and rate capability are demonstrated. ► Excellent electrochemical performance is attributed to the unique 3D nanostructure.