Pseudocapacitance contribution to three-dimensional micro-sized silicon@Fe3O4@few-layered graphene for high-rate and long-life lithium ion batteries

A one-step and scalable strategy is adopted to synthesize egg-like silicon-based anode materials for Li-ion batteries. Such an artificially designed micro-sized silicon particles are dually protected by amorphous Fe3O4 and few-layered graphene (denoted as Si@Fe3O4@FLG). This robust integrated spherical structure capitalizes on the accommodation of volume expansion of micro-sized silicon, affording a remarkable long-term electrochemical performance, i.e., superior reversible capacity of 637 mA h g(-1) (an impressive volumetric capacity of 1146.6 Ah L-1) after 1600 cycles at a large current density of 2 A g(-1). A detailed investigation into electrochemical kinetic reveals lithium ion charge storage capability greatly depended on the pseudocapacitance-controlled behavior. The impressive electrochemical performance demonstrates that the Si@Fe3O4@FLG anode has great potential to meet the challenges of next-generation large-power, long-term lifespan energy storage in use of inexpensive and scalable micro-sized silicon as anode.