Carbon-coated Fe2O3 nanocrystals with enhanced lithium storage capability

Abstract Homogeneous and highly crystalline Fe 2 O 3 nanocrystals (∼8 nm) embedded in interconnected carbon nanospheres (∼50 nm) (Fe 2 O 3 @C) have been fabricated by one-step hydrothermal reaction followed by annealing with Ar. When used as the anode materials for lithium-ion batteries, the Fe 2 O 3 @C nanospheres with 55.24 wt% Fe 2 O 3 deliver high reversible lithium storage capacity (826 mAh/g at 0.1 A/g after 20 cycles), high Coulombic efficiency (∼99%) and good cycling stability, which are much better than that of commercial Fe 2 O 3 nanoparticles. These excellent electrochemical performances could be attributed to the robust and high-conducting interconnected carbon nanospheres embedded with a mass of small Fe 2 O 3 nanocrystals, which not only can offer large quantity of accessible active sites for lithium-ion reaction as well as good conductivity and short diffusion length for electron and ion transport, but also can effectively suppress the aggregation and buffer the volume expansion of Fe 2 O 3 nanocrystals during the repeated lithiation and delithiation processes.