Ultrafine tin oxide on reduced graphene oxide as high-performance anode for sodium-ion batteries

Na-ion Battery is attractive alternative to Li-ion battery due to the natural abundance of sodium resource. Searching for suitable anode materials is one of the critical issues for Na-ion battery due to the low Na-storage activity of carbon materials. In this work, we synthesized a nanohybrid anode consisting of ultrafine SnO₂ anchored on few-layered reduced graphene oxide (rGO) by a facile hydrothermal route. The SnO₂/rGO hybrid exhibits a high capacity, long cycle life and good rate capability. The hybrid can deliver a high charge capacity of 324 mAh g_SnO2^-1 at 50 mA g^-1. At 1600 mA g^-1 (2.4C), it can still yield a charge capacity of 200 mAh g_SnO2^-1. After 100 cycles at 100 mA g^-1, the hybrid can retain a high charge capacity of 369 mAh g_SnO2^-1. X-ray photoelectron spectroscopy, ex situ transmission electron microscopy and electrochemical impedance spectroscopy were used to investigate the origin of the excellent electrochemical Na-storage properties of SnO₂/rGO.