Templating synthesis of FeO hollow spheres modified with Ag nanoparticles as superior anode for lithium ion batteries.

Ag-FeO hollow spheres are synthesized by using Ag@C core-shell matrix as sacrificial templates. The morphologies and structures of the as-prepared samples are characterized by scanning electron microscopy, X-ray powder diffraction energy dispersive, transmission electron microscopy and high resolution transmission electron microscopy. In contrast to FeO hollow spheres, Ag-FeO hollow spheres exhibit much higher electrochemical performances. The Ag-FeO composites exhibit an initial discharge capacity of 1030.9 mA h g and retain a high capacity of 953.2 mA h g at a current density of 100 mA g after 200 cycles. Furthermore, Ag-FeO electrode can maintain a stable capacity of 678 mA h g at 1 A g after 250 cycles. Rate performance of Ag-FeO electrode exhibits a high capacity of 650.8 mA h g even at 5 A g. These excellent performances can be attributed to the decoration of Ag particles which will enhance conductivity and accelerate electrochemical reaction kinetics. Moreover, the hollow structure and the constructing particles with nanosize will benefit to accommodate huge volume change and stabilize the structure.