N-doped cnt-pani based hybrid nanostructures for supercapacitor electrode

Abstract

We synthesized multicomponent hybrid nanostrcutures by variation of chemical processing routes. The hybrid nanostructure is based on nitrogen doped CNT (nCNT), polyaniline (pani) and metal oxides (MnOx & RuOx). The interaction between nCNT and pani resulted in a strong bond between protonated pyridinic N and aniline radical. Such kind of bonding is explained by proposing a radical-cation coupling model (RCCM). The strong coupling between nCNT and pani is evident from the N1s deconvoluted XPS spectra where a new peak arises at 398.9eV. Raman spectra taken before and after solution processing of nCNT-pani showed the presence of pani peaks. Due to the close interaction and strong bonding, our hybrid nanostructure (nCNT-pani) showed specific capacitance value of 1,450 F/g and 515 F/g in neutral and acidic electrolyte respectively that is comparatively higher than reported before. Similarly the electrochemical performance is further enhanced by incorporation of metal oxides in nCNT-pani via one step and two-step process. We achieved a maximum specific capacitance value (1,817 F/g) for nCNT-pani/MnOx-1 in neutral solution. Similarly, in case of nCNT-pani/RuOx-2, a specific capacitance value of (1,155 F/g) was achieved in acidic solution almost double the value of nCNT-pani. The overall good electrochemical performance exhibited by our two and three component hybrid nanostructures is considered to be because of very close interactions among them.