A Superior Sodium/Lithium-Ion Storage Material: Sea Sponge C/Sn2Fe@GO.

A well-structured anode nanomaterial, which can ensure electron and ion transport and avoid excessive pulverization, is of crucial importance to achieve high capacity with superior cycling stability for both sodium- and lithium-ion batteries (SIBs and LIBs). For the purpose of a superior rate performance, this work here has designed and successfully synthesized a new Na+/Li+ storage nanomaterial of SCS/Sn2Fe@GO through loading of a Sn2Fe nanoalloy on sea-sponge-like carbon spheres (SCSs), followed by a graphene oxide (GO) wrapping process. In such a designed composite, the SCS skeleton ensures electronic conductivity and shorts Na+ and Li+ diffusion pathways, while the Sn2Fe nanoalloy delivers a high capacity and prevents excessive pulverization. The GO shell around SCS/Sn2Fe greatly enhances the cyclability. Used as an anode, the SCS/Sn2Fe@GO nanocomposite enables a high capacity up to 660 mAh g-1 at 50 mA g-1, which is maintained without decay up to 800 cycles in SIBs, and up to 850 mAh g-1 at 500 mA g-1 after 3500 cycles in LIBs, proving its applicability in new-generation SIBs and LIBs.