Rapid coating of asphalt to prepare carbon-encapsulated composites of nano-silicon and graphite for lithium battery anodes

In order to obtain large-scale industrial silicon/carbon composites as anode materials for lithium-ion batteries, graphite-loaded nano-silicon (G@Si) composite was synthesized by a facile spray drying method, and then asphalt powders were fast fused on the surface and carbonized at 1100 °C for 2 h to obtain core–shell G@Si@C composite. The nano-Si particle was pinned on the graphite surface without bareness via asphalt carbon layer. The G@Si@C composite delivers excellent electrochemical performance with an initial reversible charge capacity of 502.5 mAh g−1 and coulombic efficiency of 87.5%, and the capacity retention is 83.4% after 400 cycles. The superior cycle performance is attributed to the carbon layer relieving volume change, stabilizing SEI film and inhibiting particle pulverization. Moreover, the outstanding high-rate discharge properties of G@Si@C composite may be owing to the preferable electrochemistry kinetics such as fast charge transfer and lithium-ion diffusion.