Graphene-based nitrogen-doped carbon sandwich nanosheets: a new capacitive process controlled anode material for high-performance sodium-ion batteries

Anode materials with capacitive charge storage (CCS) are highly desirable for the development of high-performance sodium-ion batteries (SIBs), because the capacitive process usually shows kinetically high ion diffusion and superior structural stability. Here, we report a new CCS anode material of graphene-based nitrogen-doped carbon sandwich nanosheets (G-NCs). The as-prepared G-NCs show a high capacitive contribution during the discharge/charge processes. As expected, the G-NCs exhibit excellent rate performance with a reversible capacity of 110 mA h g(-1), even at a current as high as 10 000 mA g(-1) and outstanding cycle stability (a retention of 154 mA h g(-1) after 10 000 cycles at 5000 mA g(-1)). This represents the best cycle stability among all reported carbon anode materials for SIBs, thereby showing great potential as a commercial anode material for SIBs.