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

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.