Preparation of carbon gel microspheres containing silicon powder for lithium ion battery anodes

Carbon gel microspheres containing silicon powder were successfully prepared by simply adding silicon powder to the water phase during the inverse emulsion polymerization of resorcinol with formaldehyde, followed by freeze-drying and carbonization in an inert atmosphere. SEM images and XRD profiles of the obtained carbon gel microspheres suggest that the silicon powder was successfully encased within the carbon gel microspheres. From the results of galvanostatic lithium ion charging and discharging experiments, it was found that the reversible capacity of silicon and its cyclic characteristics could be improved by encasing its powder in carbon cryogel microspheres. It is assumed that the mesoporous structure of the carbon cryogel acted as a buffering matrix which relieves the morphological changes of silicon powder which occurs during charging/discharging. (C) 2004 Elsevier Ltd. All rights reserved.