Silicon/Hollow γ-Fe2O3 Nanoparticles as Efficient Anodes for Li-Ion Batteries

Nanomaterials have triggered a lot of attention as potential triggers for a technological breakthrough in Energy Storage Devices and specifically Li-ion batteries. Herein, we report the original synthesis of well-defined silicon/iron oxide nanoparticles and its application as anode materials for Li-ion batteries. This model compound is based on earth abundant elements and allows for a full investigation of the electrochemical reactions through its iron oxide magnetic phase. The elaboration of silicon with iron oxide grown on its surface has been achieved by reacting an organometallic precursor Fe(CO)(5) with Si nanopowder and subsequent slow oxidation step in air yields hollow gamma-Fe2O3 on the Si surface. This specific morphology results in an enhancement of the specific capacity from 2000 mAh/gSi up to 2600 mAh/gSi. Such a high specific capacity is achieved only for hollow gamma-Fe2O3 and demonstrates a novel approach toward the modification of electrode materials with an earth abundant transition metal like iron. This result further emphasizes the need for precisely designed nanoparticles in achieving significant progress in energy storage.