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

Abstract

Cross-linked hard carbon materials (SFC_zGLC₁) 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, SFC₃GLC₁ delivered the highest reversible capacity of 413.1 mAh/g at 0.02 A/g with ICE ∼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).