Synthesis of α-Fe2O3 double-layer hollow spheres with carbon coating using carbonaceous sphere templates for lithium ion battery anodes

In this work, α-Fe 2 O 3 double-layer hollow spheres with carbon coating (DLHS@C) are synthesized by a general “penetration-heterogeneous nucleation” approach using carbonaceous sphere templates combined with subsequent annealing. This hierarchy hollow sphere structure with carbon coating rationally combines three advantage aspects: shorten transport length for lithium ions and charges, sufficient void space to buffer the volume expansion, and enhanced electric conductivity. When tested for lithium storage, α-Fe 2 O 3 DLHS@C composite electrode exhibits a high initial discharge capacity of 1735 mAh g -1 and the reversible capacity of 823 mAh g -1 after 100 cycles at the current density of 100 mA g -1 in the voltage range of 0.01–2.5 V (vs. Li + /Li) and retains a capacity of 470 mAh g -1 even at a large current density of 500 mA g -1 after 500 cycles. The α-Fe 2 O 3 DLHS@C electrode demonstrates excellent electrochemical properties with high capacity, good cycling stability, and excellent rate capability as potential anode material for lithium ion batteries.