Antimony nanocrystals self-encapsulated within bio-oil derived carbon for ultra-stable sodium storage

Integrating carbon-coating and nanostructuring has been considered as the most promising strategy to accommodate the dramatic volume expansion represented by high-capacity antimony (Sb) upon sodiation. Suitable coating source and synthetic strategy that are both economical and strong are yet to be explored. In this regard, by using renewable bio-oil as carbon source and self-wrapping precursor, robust Sb@C composite anode with Sb nanoparticles homogeneously impregnated into the cross-linked 2D ultrathin carbon nanosheets is developed via a facile NaCl template-assisted self-assembly and followed carbothermal reduction method. Such judiciously crafted interconnected macroporous framework can mitigate of mechanical stress and alleviate the volume change of inner Sb, guaranteeing high-performance sodium-ion battery anode. At a current density of 0.1 A g⁻¹, ultrahigh reversible capacity of 520 mAh g⁻¹ can be achieved. Notably, a stable capacity of 391 mAh g⁻¹ is even retained after 500 cycles at 1 A g⁻¹. Such a facile and cost-effective synthetic method is promising for high-performance sodium-ion batteries.