▎ 摘　　要

In this report, a yolk-shell-structured Si/graphene (Si/GR) material has been designed and successfully fabricated as an anode for lithium-ion batteries (LIBs). With this approach, Si@Ni composite particles were fabricated by electroless deposition of a nickel template directly on silicon; then, three-dimensional (3D) graphene layers were grown in situ around the composite particles to obtain a Si@Ni@GR structure. After removing the nickel interlayer, some voids were generated between the silicon particles and the graphene layers, thus forming a Si@void@GR structure. The coexistence of voids and the graphene layer may provide a synergistic effect. The voids may reserve space for silicon particles during volume expansion and buffer the mechanical pressure of the graphene layer. Meanwhile, the graphene cover may enhance lithium-ion transport efficiency and electron transport rate, thereby improving the electrical conductivity of the anode. The well-coated layers can also prevent the Si particles from being directly exposed to electrolyte, which can promote the formation of a stable SEI film and reduce the irreversible consumption of Li+. Therefore, such unique yolk-shell structures offer the resultant Si@void@GR electrode a high reversible discharge capacity (1595 mAh g(-1) after 100 cycles at a current density of 500 mA g(-1)) and the capacity to deliver a discharge capacity of 990 mAh g(-1) even at a high current density of 4.8 A g(-1).