Silicon Nanowires Passivated by TiO 2 Layer for Supercapacitors in Aqueous Electrolyte

Silicon nanowires (SiNWs) passivated by TiO 2 have been produced and used as electrode material for supercapacitor in aqueous electrolyte. SiNWs were produced by metal-assisted chemical etching method, subsequently passivated with a TiO 2 layer by a simple dripping method. The TiO 2 -coated SiNWs were thermal treated at 400 °C for 1 h in air. The capacitive properties of the electrode materials were investigated. The TiO 2 -coated SiNWs presented lower capacitance while higher rate capability compared to bare SiNWs in the aqueous environment. The cyclic stability of the electrode was improved significantly by the passivation of TiO 2 onto the SiNWs.