Ultrafine Sn Nanoparticles Anchored on Nitrogen- and Phosphorus-Doped Hollow Carbon Frameworks for Lithium-Ion Batteries

Nanosized Sn-based materials as anodes in lithium-ion batteries suffer from capacity fading because of aggregation and severe volume change (∼300 %) during the charge/discharge process. We developed ultrafine Sn nanoparticles anchored on a graphene-hollow carbon framework as anode material. Graphene-hollow carbon framework (G-HCF) anchors ultrafine Sn nanoparticles on its surface to prevent aggregation. The hollow structure can provide a buffer space to accommodate the volume expansion of the Sn particles and prevents electrode pulverization during the charge/discharge process. Furthermore, the interconnected hollow carbon structure enables rapid lithium-ion and electron transport to give the enhanced rate performance. Also, the G-HCF was doped with nitrogen and phosphorus to stabilize its electrochemical performance. Consequently, the as-prepared G-HCF-Sn composite exhibited a highly stable cycling performance, even at a current density of 1.0 A/g (specific capacity of 1048 mA h/g after 1000 cycles).