Synthesis of presodiated B, N Co-doped carbon materials and application in sodium ions batteries with enhanced initial coulombic efficiency

Heteroatoms doped carbon-based materials have attracted abundant attention as an anode material in highenergy density and low-cost sodium ions batteries (SIBs). However, the low initial Coulombic efficiency (ICE) resulted from the irreversible Na trapping and the formation of solid electrolyte interphase (SEI) is denounced in the practical application. In this work, presodiated B and N co-doped carbons are fabricated by a facial one-step synthetic process employing graphitic carbon nitride (g-C3N4) as precursor and NaBH4 as both presodiation agent and B sources. The high doping levels of B and N in the resultant carbon materials lead to a promising Na+ storage capability (308 mAh g-1 at 0.05 A g-1) when served as the anode in SIBs. More importantly, desirable ICE as high as 96.1% was recorded for the obtained presodiated B, N co-doped carbon material benefiting from the pre-incorporated sodium, which passivates the irreversible reactive sites. This work provides a novel route to realize simultaneous presodiation and B, N co-doping within carbon materials, enabling promising Na+ storage capability and enhanced ICE for application in SIBs.