Spin-Coated Silicon Nanoparticle/Graphene Electrode as a Binder-Free Anode for High-Performance Lithium-Ion Batteries

Si has been considered as a promising anode material but its practical application has been severely hindered due to poor cyclability caused by the large volume change during charge/discharge. A new and effective protocol has been developed to construct Si nanoparticle/graphene electrodes with a favorable structure to alleviate this problem. Starting from a stable suspension of Si nanoparticles and graphene oxide in ethanol, spin-coating can be used as a facile method to cast a spin-coated Si nanoparticle/graphene (SC-Si/G) film, in which graphene can act as both an efficient electronic conductor and effective binder with no need for other binders such as polyvinylidenefluoride (PVDF) or polytetrafluoroethylene (PTFE). The prepared SC-Si/G electrode can achieve a high-performance as an anode for lithium-ion batteries benefiting from the following advantages: i) the graphene enhances the electronic conductivity of Si nanoparticles and the void spaces between Si nanoparticles facilitate the lithium ion diffusion, ii) the flexible graphene and the void spaces can effectively cushion the volume expansion of Si nanoparticles. As a result, the binder-free electrode shows a high capacity of 1611 mA·h·g^-1 at 1 A·g^-1 after 200 cycles, a superior rate capability of 648 mA·h·g^-1 at 10 A·g^-1, and an excellent cycle life of 200 cycles with 74% capacity retention.