Polyoxometalate-Assisted Synthesis of TiO2 Nanoparticles and Their Applications in Aqueous Hybrid Electrochemical Capacitors

Abstract

A mild hydrolysis method was proposed to synthesize TiO₂ nanoparticles (NPs), in which polyoxometalate adjusted the hydrolyzation reaction rate and controlled the size of TiO₂. The resultant TiO₂ NPs were fully characterized via XRD, SEM, TEM, XPS. The electrochemical investigations demonstrated that the as-obtained TiO₂ NPs delivered higher specific capacitance than that of bulk and commercial samples in lithium-ion aqueous solution. Furthermore, the charge storage mechanism of TiO₂ NPs was also studied. More importantly, the aqueous hybrid capacitors based on activated carbon (AC) and TiO₂ were constructed and their electrochemical performance were fully investigated in aqueous solutions.