High performance energy storage applications with titanium based nanocomposites

In this work, the nanocomposite material consisting of biomass-derived activated carbon, titanium dioxide (anatase phase) and conductive polymer was prepared and tested as a supercapacitor electrode material. TiO2 nanoparticles were coated by biomass-derived activated carbon via a simple, environmentally friendly and one-step hydrothermal carbonization method. Successive pyrolysis process increased the carbon content of the material by degradation of hydroxyl groups. As a result of increasing carbon content in the structure, the mechanical properties of titanium dioxide have been improved. PEDOT:PSS coating was applied to reduce the wide band gap of anatase TiO2 and thus improve the electrical conductivity of the synthesized composite material. Chemical compositions of the synthesized materials were determined by elemental analysis. XRD patterns showed that the anatase phase of TiO2 was maintained after the heat treatments and the polymer coating. The crystalline spherical nanoparticles with a thin carbon layer were observed from SEM and TEM images. The thermal stabilities of the materials were investigated by TGA analysis. FTIR analyses were used to investigate chemical bonding. The pore size distributions and the specific surface area of the synthesized materials were calculated by the DFT and BET method, respectively. The TiO2/C/PEDOT:PSS ternary composite showed a mesoporous structure with a surface area of 102,3 m2g-1. The electrochemical properties of the TiO2/C/PEDOT:PSS composite was investigated by using a three-electrode cell configuration at the potential range of 0 to 1 V (vs. Ag/AgCl) in 1M H2SO4 aqueous electrolyte. The TiO2/C/PEDOT:PSS ternary composite electrode showed a high specific capacitance of 189.4 Fg-1 at a current density of 0.25 Ag-1 due to the synergistic effect of its components. The capacitance is higher than the previously reported values for TiO2 and PEDOT:PSS-based nanocomposites. In addition, TiO2/C/PEDOT: PSS ternary composite material showed 98% capacitance retention and high electrochemical stability after 1500 cycles. As a result, the composite material showed promising results for energy storage applications.