Graphene enhanced silicon/carbon composite as anode for high performance lithium-ion batteries

Abstract

Silicon-based anode materials for lithium ion batteries (LIBs) have become a hot research topic due to their remarkably high theoretical capacity (4200 mA h g⁻¹). However, the large volume change (>300%) of Si electrodes during the lithium ion insertion/extraction process leads to a rapid decay of the reversible capacity. In our report, carbon/graphene double-layer coated-silicon composite (Si/carbon/graphene, Si/C/G) is prepared via a facile hydrothermal process. It is demonstrated that the Si/C/G composite displayed an exceedingly ameliorated electrochemical performance in both cycling stability and rate capability. The specific capacity of the Si/C/G electrode is maintained at 2469 mA h g⁻¹ after 50 cycles under 0.2 A g⁻¹, and above 1500 mA h g⁻¹ after 300 cycles at 2 A g⁻¹. More notably, even at an ultrahigh rate of 32 A g⁻¹, the specific capacity could still reach 471 mA h g⁻¹. Hence the presented simple approach enables massive fabrication of the Si/C/G composite as a promising anode material for high performance LIBs.