On the Practical Applicability of Rambutan-like SiOC Anode with Enhanced Reaction Kinetics for Lithium-Ion Storage

Silicon oxycarbide (SiOC) possesses great potential in lithium-ion batteries owing to its tunable chemical component, high reversible capacity, and small volume expansion. However, its commercial application is restricted due to its poor electrical conductivity. Herein, rambutan-like vertical graphene coated hollow porous SiOC (Hp-SiOC@VG) spherical particles with an average diameter of 302 nm are fabricated via a hydrothermal treatment combined CH4 pyrolysis strategy for the first time. As-prepared Hp-SiOC@VG exhibits a large reversible capacity of 729 mAh g(-1) at 0.1 A g(-1), remarkable cycling stability of 98% capacity retention rate after 600 cycles at 1.0 A g(-1) and high rate capability of 289 mAh g(-1) at 5.0 A g(-1) owing to the unique structure of the particles and the electrical conductivity of the vertical graphene. Density functional theory calculations reveal that the higher contents of SiO3C and SiO2C2 structural units in the SiOC are beneficial to enhance the Li+ storage capacity. Additionally, the full-cell assembled with Hp-SiOC@VG and LiFePO4 delivers up to 74% capacity retention rate after 100 cycles at 0.2 A g(-1). This work reports a new way for the facile preparation of template-free hollow porous materials and expands the application prospects of SiOC-based anode for lithium-ion batteries.