Face-to-Face Contact and Open-Void Coinvolved Si/C Nanohybrids Lithium-Ion Battery Anodes with Extremely Long Cycle Life

To develop high-performance anode materials of lithium-ion batteries (LIBs) instead of commercial graphite for practical applications, herein, a layer of silicon has been well-anchored onto a 3D graphene/carbon nanotube (CNT) aerogels (CAs) framework with face-to-face contact and balanced open void by a simple chemical vapor deposition strategy. The engineered contact interface between CAs and Si creates high-efficiency channels for the rapid electrons and lithium ions transport, and meanwhile, the balanced open-void allows the free expansion of Si during cycling while maintaining high structural integrity due to the robust mechanical strength of 3D CAs framework. As a consequence, the as-synthesized Si/CAs nanohybrids are highly stable anode materials for LIBs with a high reversible discharge capacity (1498 mAh g(-1) at 200 mA g(-1)) and excellent rate capability (462 mAh g(-1) at 10 000 mA g(-1)), which is much better than Si/graphene-CNTs-mixture (51 mAh g(-1) at 10 000 mA g(-1)). More significantly, it is found that the Si/CAs nanohybrids display no obvious capacity decline even after 2000 cycles at a high current density of 10 000 mA g(-1). The present Si/CAs nanohybrids are one of the most stable Si-based anode materials ever reported for LIBs to date.