Mesoporous Nanocomposites of Mn and Ti Oxides for Supercapacitors

摘要

In this investigation, several nanocomposites with varying amounts of Mn and Ti oxides were prepared using surfactant assisted sol-gel method. To prepare these nanocomposites, sol-A with Ti precursor and sol-B containing Mn precursor were separately prepared using the required precursor amounts in ethanol and 5-30 wt.% pluronic 123 surfactant. Gelation was accomplished by the addition of DI water and catalyzed by HCl. The gels were aged for 24 hrs, dried at 80°C for 12 hrs and calcined at 500°-1000°C for 5 hrs. These powdered electrode materials were analyzed by x-ray diffraction and BET surface area analysis. For the nanocomposite prepared with Mn:Ti at 65:35 wt.% and calcined at 500°C, both anatase and rutile phases alongwith Mn_2O_3 were observed. As calcination temperature increased to 1000°C, rutile and Mn_2O_3 phases were decreased with the formation of MnTiO_3. BET SSA of 30.6 m~2/g was observed for the powdered material calcined at 500°C with avg. pore diameter of 7.5 nm. Supercapacitors were fabricated using these nanocomposites and cyclic voltammetry measurements were performed to infer specific capacitance. Higher specific capacitance of 125 F.g~(-1) was observed for the supercapacitor fabricated with the Mn:Ti nanocomposite calcined at lower temperature of 500°C.