Core-Shell-Structured SiOx-C Composite for Lithium-Ion Battery Anodes
Authors: Zhang, JY; Ma, PP; Zhang, XM; Liu, Z; Zheng, J; Zuo, YH; Xue, CL; Cheng, BW; Li, CB
Volume: 7 Issue: 4 Published: APR 2019 Language: English Document type: Article
A simple method to synthesize a uniform composite material consisting of wet-milled SiOx core and carbon shell is studied. This SiOx-C core-shell composite is then used as anode materials for lithium-ion batteries, with wet-milled SiOx and raw SiOx anodes used for comparison. It is found that the batteries fabricated with wet-milled SiOx-C composite show the best cyclic performance and excellent rate capability compared with wet-milled SiOx and raw SiOx. This approach is beneficial because of the reduced size of wet-milled SiOx powders. The coating of carbon shell is effective in improving the conductivity of SiOx and diminishing the volume effect during lithiation/delithiation processes. Moreover, the Li2O and Li4SiO4 generated in the first cycle further suppress the volume effects. Under the galvanostatic mode with charging and discharging current density of 0.1 Ag-1, the wet-milled SiOx-C composite electrode delivers an initial reversible capacity of 1279 mAh g(-1), with a capacity retention as high as 97.3% (1244 mAh g(-1)) even after 170 cycles and coulombic efficiency as high as 99.8%. This approach is simple and has great potential for the large-scale production of high-performance SiOx-based anode materials.