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

摘要

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 micronlevel 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 200mA g(-1), with a capacity retention of 88.3% as against the first cycle. The electrode delivers a reversible capacity of 423.1mA h g(-1), 280.8 mA h g(-1) and 190.3mA h g(-1) at the current density of 1 A g(-1), 3 Ag-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. (C) 2018 Elsevier B.V. All rights reserved.