Surface regulation of Si composite anode via synergistic coupling and Ti[sbnd]C bond for stable cycling lithium-ion battery

Abstract

Silicon holds bright promise as the anode material for next-generation lithium-ion batteries (LIBs). Unfortunately, it is limited by enormous volume expansion and fast capacity fading in long-cycling or large current density. Here, we propose an in-situ assembling path to form a stable Si nanocomposite by introducing bicontinuous TiO2-C layer and graphene nano-sheets, and further enhance the stability for long-term LIBs. The enhanced synergistic coupling of graphene and bicontinuous TiO2-C layer and introduced TiC bond effectively improve long-cycling structural stability of Si nanocomposite for promising LIBs anode material. This anode material exhibits high capacity, long-term cycling and high-rate performance. Especially, it showed the high reversible capacities of 2147.6 mA h g−1 at 0.5 A g−1 after 800 cycles and 1328.2 mA h g−1 at 2 A g−1 after 500 cycles, which is much better than that of TiO2-C@Si and nano Si anodes. Moreover, the full cell including this composite anode and commercial LiFePO4 cathode exhibits a high capacity retention after 100 cycles. Our work demonstrates that this surface functionalization strategy can enhance synergistic coupling and introduce TiC bond to regulate the stability of Si nanocomposite as long-cycling LIBs anode.