Hollow silica spheres with facile carbon modification as an anode material for lithium-ion batteries

Hollow silica (H-SiO2) spheres are prepared via a self-assembly approach without sacrificial templates. To address the poor electrical conductivity and mechanical stability problems of H-SiO2, carbon coating is adopted to modify the H-SiO2 spheres through a facile solution-mixing method. In the obtained micron-level H-SiO2/C composite, the carbon coating layer can act as a mechanical support layer to maintain the structure stability of the H-SiO2 spheres, while the inner hollow space can accommodate the volume expansion during cycling. Moreover, the N-doped carbon can provide a fast electron transfer channel for the H-SiO2/C electrode during lithiation/delithiation process, helping the electrode exhibiting significantly improved cycling and rate performance. The reversible capacity of the H-SiO2/C electrode after 400 cycles is 564.0 mA h g−1 at a current density of 200 mA g−1, with a capacity retention of 88.3% as against the first cycle. The electrode delivers a reversible capacity of 423.1 mA h g−1, 280.8 mA h g−1 and 190.3 mA h g−1 at the current density of 1 A g−1, 3 A g−1 and 5 A g−1, respectively. This work provides a facile strategy for the large-scale production of H-SiO2/C anode materials for LIBs. [Display omitted] •Hollow silica spheres are prepared without sacrificial templates.•A facile solution-mixing carbon coating process is adopted.•The carbon provides mechanical support and fast electron transfer channel.•The micron-level H-SiO2/C composite exhibits improved cyclic/rate performance.