Multiwall carbon nanotube-poly(4-styrenesulfonic acid) supported polypyrrole/manganese oxide nano-composites for high performance electrochemical electrodes

Poly(4-styrenesulfonic acid) (PSS) dispersed multiwall carbon nanotubes (MWCNTs) are used as a support for polypyrrole (PPy)/MnO2 in a supercapacitor electrode. Synergetic interaction between polypyrrole and MnO2 significantly improves the electrical properties and the mechanical stability of the electrode that yields high rate capability. The (–SO3−) surface functionalities on MWCNT-PSS facilitate an ordered growth, and the molecular level dispersion of MnO2 in PPy matrix enhances the electrode performance. As an electrochemical electrode the MWCNT-PSS/PPy:MnO2 nano-composite exhibits ∼268 F g−1 specific capacitance at 5 mV s−1. The excellent rate capability and stability of the electrode is demonstrated by only 7% fade in the specific capacity at 100 mV s−1 (compared to the available capacity at 5 mV s−1) and 10% fade in the same after 5000 CV cycles. Specific capacitance of PPy:MnO2 component in the nano-composite is as high as 412 F g−1 in 0.5 M Na2SO4 electrolyte. Electrical conductivity of the MWCNT-PSS/PPy nano-composite is significantly improved upon inclusion of MnO2 in molecular level dispersion.