Design of cross-linked hard carbon with high initial coulombic efficiency for sodium-ion batteries anode

Cross-linked hard carbon materials (SFC(z)GLC(1)) were prepared from Shenfu bituminous coal (SFC) and glucose (GLC) via a one-step carbonization method. The relationship between the microstructure and Na+ storage behavior was explored. The initial coulombic efficiency (ICE) was related to surface defects. Owing to abundant porous structure and low defects, SFC(3)GLC(1) delivered the highest reversible capacity of 413.1 mAh/g at 0.02 A/g with ICE similar to 84 % and excellent cycling stability (89.4 % capacity retention over 200 cycles). This work provides a facile route to develop high-performance, low-cost carbon-based anodes for next-generation sodium-ion batteries (SIBs).