Fullerene-Intercalated Graphitic Carbon Nitride as a High-Performance Anode Material for Sodium-Ion Batteries

Two-dimensional (2D) graphitic carbon nitride (g-CN) is a promising anode material for sodium-ion batteries (SIBs), but its insufficient interlayer spacing and poor electronic conductivity impede its sodium storage capacity and cycling stability. Herein, we report the fabrication of a fullerene (C-60)-modified graphitic carbon nitride (C-60@CN) material which as an anode material for SIBs shows a high-reversible capacity (430.5 mA h g(-1) at 0.05 A g(-1), about 3 times higher than that of pristine g-CN), excellent rate capability (226.6 mA h g(-1) at 1 A g(-1)) and ultra-long cycle life (101.2 mA h g(-1) after 5000 cycles at 5 A g(-1)). Even at a high-active mass loading of 3.7 mg cm(-2), a reversible capacity of 316.3 mA h g(-1) can be obtained after 100 cycles. Such outstanding performance of C-60@CN is attributed to the C-60 molecules distributed in the g-CN nanosheets, which enhance the electronic conductivity and prevent g-CN sheets from restacking, thus resulting in enlarged interlayer spacing and exposed edge N defects (pyridinic N and pyrrolic N) for sodium-ion storage. Furthermore, a sodium-ion full cell combining C-60@CN anode and NVPF@rGO cathode provides high-coulombic efficiency (>96.5%), exceptionally high-energy density (359.8 W h kg(anode)(-1) at power density of 105.1 W kg(anode)(-1)) and excellent cycling stability (89.2% capacity retention over 500 cycles at 1 A g(anode)(-1)). This work brings new insights into the field of carbon-based anode materials for SIBs.