Ferrocene as a Novel Additive to Enhance the Lithium-Ion Storage Capability of SnO₂/Graphene Composite

Improving the reversibility of conversion reaction is a promising way to enhance the lithium-ion storage capability of SnO₂-based anodes. Herein, we report ferrocene as a novel additive to improve the Li-ion storage performance of the SnO₂/graphene (SnO₂/G) composite. Through a simple mixing method, ferrocene can be uniformly dispersed into the SnO₂/G electrode. It is found that the ferrocene additive can effectively suppress the agglomeration of Sn/SnO₂ and retain the nanoscale Sn/Li₂O interface. Furthermore, metallic Fe is formed from ferrocene in the discharge process and acts as a catalyst to promote the reversible conversion between Sn/Li₂O and SnO₂. As a result, the SnO₂/G electrode with the addition of 10 wt % ferrocene (10%Fc-SnO₂/G) exhibits a superior Li-ion storage performance. It displays a reversible capacity of up to 1084.5 mAh g^-1 at 0.1 A g^-1 after 150 cycles with a good rate capability (752 mAh g^-1 at 1 A g^-1). In addition, the 10%Fc-SnO₂/G electrode can retain a capacity of 787.2 mAh g^-1 at 0.5 A g^-1 after 220 cycles. This work demonstrates the promising additive of ferrocene in enhancing the reversible capacity of SnO₂-based anodes for lithium-ion batteries.