Micro-sized spherical silicon@carbon@graphene prepared by spray drying as anode material for lithium-ion batteries

The micro-sized silicon@carbon@graphene spherical composite (Si@C@RGO) has been prepared by an industrially scalable spray drying approach and a subsequent calcination process. The obtained Si@C@RGO anode exhibits a high initial reversible specific capacity of 1599 mAh g⁻¹ at a current density of 100 mA g⁻¹ with a good capacity retention of 94.9% of the original charge capacity at a higher current density of 200 mA g⁻¹. Moreover, the Si@C@RGO anode shows a high reversible specific capacity of 951 mAh g⁻¹ even at a high current density of 2000 mA g⁻¹. The excellent cycling stability and superior rate capability are attributed to the unique structural design of carbon coating and wrapped by highly conductive graphene. The combination of carbon shells and flexible graphene can effectively enhance the electrical conductivity of the composite and accommodate significant volume changes of silicon during cycling. The presented spray drying strategy is adaptable for large-scale industrial production of Si-based composite, and it can be extended to the design of other promising micro-sized electrode materials. - Highlights: • Micro-sized spherical Si@C@RGO was synthesized by spray drying process. • The Si@C@RGO composite exhibits excellent electrochemical performance. • The unique structure significantly enhances the conductivity of silicon.