Flexible Silicon/Titanium Dioxide/Reduced Graphene Oxide Self-Standing Electrode with High Performance and High Stability for Lithium-Ion Batteries

The great volume expansion and unstable nature of the solid electrolyte interface film of silicon (Si) are central issues that obstruct the advancement of the Si-based electrode despite its high theoretical capacity and abundant resources. Here a kind of flexible silicon/titanium dioxide/reduced graphene oxide (Si/TiO2/rGO) self-standing electrode is constructed without the assistance of a binder and conductive agent. Briefly, the Si nanoparticle is coated with TiO2 via a sol–gel process, and then the core–shell structured Si/TiO2 is assembled with GO using chitosan as the cross-linker followed by freeze-drying, pressing, and annealing at an ammonia/argon (NH3/Ar) atmosphere. In this structure, TiO2 and rGO provide dual protection for Si, and a continuous conductive path is formed. Additionally, nitrogen doping by NH3 and chitosan further strengthens the lithium storage performance. The fabricated Si/TiO2/rGO film electrode demonstrates excellent rate performance over a broad range of current densities and keeps a reversible capacity of 1333.8 mAh g–1 after 200 cycles operated at 200 mA g–1.