▎ 摘　　要

The vast volume expansion of Si anode during lithiation process leads to poor cyclability and low initial coulombic efficiency (ICE), and thus seriously hampers its applications in lithium-ion batteries (LIBs). To overcome these obstacles, in this study, a double core-shell structure stabilized hierarchical porous Si (p -Si) microsphere was synthesized through a graphene-involved electrostatic self-assembly process coupled with a solvent-confined TiO2 (sc-TiO2) monomicelle assembly strategy. The advanced solvent-confined monomicelle assembly process enables the uniform deposition of ultra-thin TiO2 layer on p-Si@graphene (p-Si@G) microsphere. The G/sc-TiO2 hybrid double shell layer can significantly consolidate porous structure of p-Si microsphere and simultaneously improve the ICE value of p-Si@G@sc-TiO2 microsphere. The resulting p-Si@G@sc-TiO2 composite shows a high capacity value of 2597.9 mAh g(-1) at 0.2 A g(-1) with a high ICE value of 80.59%. The p-Si@G@sc-TiO2 composite also demonstrates excellent rate capability with capacity of 802.53 mAh g(-1) at 8 A g(-1) and outstanding cyclability with capacity retention of 68% (1005.1 mAh g(-1)) after 300 cycles at 2 A g(-1), superior to that of p-Si, p-Si@G as well as p-Si@G@TiO2 microsphere preparing by traditional sol-gel TiO2 coating method, suggesting its promising applications in LIBs. (c) 2022 Elsevier Ltd. All rights reserved.