In Situ Wrapping Si Nanoparticles with 2D Carbon Nanosheets as High-Areal-Capacity Anode for Lithium-Ion Batteries

Silicon (Si) has aroused great interest as the most attractive anode candidate for energy-dense lithium-ion batteries (LIBs) in the past decade because of its significantly high capacity and low discharge potential. However, the large volume change during cycling impedes its practical application, which is more serious in the case of high mass loading. Designing Si anode with high mass loading and high areal capacity by a simple, scalable, and environmentally friendly method is still a big challenge. Herein, we report in situ one-pot synthesis of Si/C composite, where Si nanoparticles are wrapped by graphene-like 2D carbon nanosheets. After 500 cycles at 420 mA g–1, the Si/C anode displays a gravimetric capacity of 881 mAh g–1 with 86.4% capacity being retained. More specially, a high areal capacity of 3.13 mAh cm–2 at 5.00 mg cm–2 after 100 cycles is achieved. This study demonstrates a novel route for the preparation of the Si/C composite with high material utilization and may expand the possibility of future design Si-based anode with high areal capacity for high energy LIBs.