Tailoring graphitic nanostructures in hard carbons as anode materials achieving efficient and ultrafast sodium storage

Hard carbons appear to be promising anode candidates in high-performance sodium-ion batteries (SIBs) for large-scale stationary energy storage due to their large interlayer distance and amorphous structure, which facilitate sodium ions insertion/desertion. However, several major hurdles to address are poor rate performances and the low initial coulombic efficiency (ICE). Herein, a facile strategy to tailor hard carbons with graphitic nanostructures and rational specific surface area is proposed to improve sodium storage. Resin-derived carbon nanobroccolis (CNB) with in situ decorated graphitic nanostructures have been successfully synthesized by self-assembly and low-temperature catalytic carbonization process. As a result, attribute to in situ tailored graphitic nanostructures in hard carbons and rational specific surface area, CNB electrodes possess less charge transfer resistance and excellent sodium ions diffusion kinetics and successfully achieve fast and efficient sodium storage. When used as anode for sodium-ion batteries, CNB electrodes exhibit excellent high-rate capability of 137 mAh g(-1) at 1000 mA g(-1) and enhanced ICE of 52.6%. Our strategy reported here opens a door to design high-performance carbon anode materials for SIBs particularly focusing on efficient sodium ions storage and fast sodium ions diffusion.