Abstract:To increase the service life of silicon particles used in the lithium-ion batteries, a linear carbon material was used to form a sponge structure. This linear material is obtained by microwave processing polypyrrole. On the sponge structure, a layer of graphene was covered to form a double layer structure. This double layer structure did not change the volume expansion of silicon particles but provided a buffer space for the expansion of silicon and prevented silicon particles detached from the collector during the charge/discharge cycle process. Then the capacity and cycle performance of the battery was improved. When the Si particles with the size of 0.5~5μm used in the electrodes, it delivers a capacity as high as 829.6 mAh?g-1 after 100 cycles at the current density of 500 mA?g-1.