Self-assembly of disordered hard carbon/graphene hybrid for sodium-ion batteries

• Disordered hard carbon/graphene hybrid was successfully prepared.
• Unique structure with carbon layers and numerous microspheres growing on graphene.
• High capacity and rate capability as anode material for SIBs.

Disordered hard carbon/graphene (C@G) hybrid is successfully designed and prepared for the first time through a facile route. SEM and TEM analyses show the uniform distribution of carbon microspheres and carbon layers on the surface of graphene. As an anode material of sodium-ion batteries, such a construction could ensure an effective contact area with the electrolyte and offer massive active sites. It displays a stable sodium storage capacity of ∼300 mAh g−1 after 100 cycles at a current density of 50 mA g−1 and exhibits an excellent rate performance. The unique structure and advantageous synergistic effect between disordered hard carbon and graphene make a significant contribution to the good Na+ insertion/extraction property.