Enhanced Performance of TiO2 Based Supercapacitor By MnO2 Modification

Titanium dioxide (TiO₂) has been considered one of the promising candidates in supercapacitors due to its low cost, electrochemical stability, natural abundance, high surface area, low toxicity, and easy preparation in defined nanoscale dimensions. In spite of its outstanding stability over a large operation window, its specific capacitance is substantially lower than those of other pseudocapacitive metal oxides. In this study, we have demonstrated that the specific capacitance of TiO₂ can be dramatically improved by surface modification with MnO₂. The composite electrode containing 18 wt.% MnO₂ exhibits a high specific capacitance of 738 F/g at 2 mV/sec, which is substantially higher than those of both pristine TiO₂ and MnO₂ electrode, while having an operating potential window of nearly 2 V in an aqueous electrolyte. In addition, the TiO₂-MnO₂ supercapacitor exhibits 73 % capacitance retention with cycling up to 5000 cycles. In view of the energy storage capacity, DE=1/2 CV²_, this new composite electrode holds great promise for next-generation high-energy supercapacitors.