Si, Si/Cu core in carbon shell composite as anode material in lithium-ion batteries

Si core in carbon shell (C/Si) composites were synthesized through an inverse emulsion polymerization of resorcinol-formaldehyde (RF) performed in the presence of silicon powders, followed by carbonization in an inert atmosphere. SEM, EDS and XRD analyses of the obtained carbon gel microspheres showed that the Si powders were encapsulated within the carbon gel microspheres. The C/Si composite exhibited a reversible lithium storage capacity of 910 mA h g^{- 1} when used as anode in lithium-ion cells. Furthermore, the addition of Cu for Si core in carbon shell was also investigated to enhance the cycleability. It was shown that the addition of Cu further improved the cycling performance of the composite. The proposed process paves the way to prepare high performance anode materials for lithium-ion batteries.