High specific energy ternary nanocmposite polyaniline:Manganeese dioxide@ MWCNT electrode for asymmetric supercapacitor

Abstract

• A co-axial system of polyaniline and MnO 2 was generated over functionalized MWCNT. • An asymmetric supercapacitor device is fabricated which can be cycled in wide voltage window of 2 V. • Due to synergism, electrochemical performance is enhanced. A layer of highly dispersed manganese oxide (MnO 2 ) nanoparticles in polyaniline (PANI) was deposited over functionalized MWCNT using insitu chemical polymerization. Obtained Coaxial MWCNT/PANI:MnO 2 ternary nanocomposite was used as positive electrode with MWCNT negative electrode in an asymmetric supercapacitor (ASC) device. The proposed design utilizes the pseudo capacitive charge in a different potential range of the ASC device. Microstructural investigations confirmed the wrapping of MWCNT by a layer of MnO 2 dispersed PANI. This leads to highly porous and homogeneous morphology of the ternary nanocomposite. Due to synergism between PANI and MnO 2 nanoparticles over MWCNT, the electrical properties of the ternary nanocomposite are significantly improved. It is observed that the proposed ASC device can be cycled up to a cell voltage 2.0 V reversibly. The above combination of materials in ASC device exhibited very high specific energy 190 Wh/kg and specific power at 1 mA/cm 2 . This device demonstrated better rate capability by maintaining 78% specific capacitance after continuously 2000 charge discharge cycles.