Enhanced lithium storage performance of silicon anode via fabricating into sandwich electrode

Silicon electrode with sandwich structure as anode of lithium ion batteries is fabricated by adding a carbon layer between current collector and active coating. The prepared silicon electrode with the sandwich structure can exhibit high reversible capacity of 2500 mAh g^-1 for 30 cycles, which is much higher than that of bare silicon electrode with normal structure. The electrochemical impedance spectroscopy and electrode morphologies characterizations show that the improved performance of sandwich electrode is attributed to the carbon layer, which not only enhances the electric conductivity at the current collector/active coating interface but also releases the rigid stress caused by volume change of silicon. The results demonstrate that such sandwich structure is a potential facile method for performance improvement of silicon-based anode compared with the previous reports.