Fe/amorphous SnO2 core-shell structured nanocapsules for microwave absorptive and electrochemical performance

Fe nanocapsules with an Fe nanoparticle core and an amorphous SnO2 shell have been synthesized by the modified arc discharge method. The microwave absorption properties and electrochemical performances of Fe/amorphous SnO2 nanocapsules were investigated. The synergistic effect of magnetic loss in the Fe nanoparticles core and dielectric loss in the SnO2 shell gave the Fe/SnO2 nanocapsules excellent microwave absorption properties. The reflection loss (RL) value of the Fe/SnO2 nanocapsule-paraffin composite is -39.2 dB at 16.8 GHz at the absorbent thickness of 2 mm and the absorption bandwidth with the RL below -20 dB is up to 10.6 GHz (from 7.4 to 18 GHz) for the absorber with the thickness of 2-3.8 mm. When evaluated as anode materials for lithium-ion batteries, the Fe/amorphous SnO2 nanocapsules deliver an initial discharge of 1558.7 mA h g(-1) at 38 mA g(-1) and maintain a reversible capacity of 698.2 mA h g(-1) over 100 cycles, which is attributed to the amorphous SnO2 nanoshell.