Manganese oxide embedded polypyrrole nanocomposites for electrochemical supercapacitor

• Published in: Electrochimica acta 2008-11, Vol.53 (26), p.7690-7695
• Main Authors: Sharma, R.K., Rastogi, A.C., Desu, S.B.
• Format: Article
• Language: English
• Subjects: Applied sciences; Capacitors. Resistors. Filters; Electrical engineering. Electrical power engineering; Exact sciences and technology; MnO 2 nanocomposite; Polypyrrole; Specific capacitance; Supercapacitor; Various equipment and components
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2008.04.028

MnO 2 embedded PPy nanocomposite (MnO 2/PPy) thin film electrodes were electrochemically synthesized over polished graphite susbtrates. Growing PPy polymer chains provides large surface area template that enables MnO 2 to form as nanoparticles embeded within polymer matrix. Co-deposition of MnO 2 and PPy has a complimentary action in which porous PPy matrix provides high active surface area for the MnO 2 nanoparticles and, on the other hand, MnO 2 nanoparticles nucleated over polymer chains contribute to enhanced conductivity and stability of the nanocomposite material by interlinking the PPy polymer chains. The MnO 2/PPy nanocomposite thin film electrodes show significant improvement in the redox performance as cyclic voltammetric studies have shown. Specific capacitance of the nanocomposite is remarkably high (∼620 F g −1) in comparision to its constituents MnO 2 (∼225 F g −1) and PPy (∼250 F g −1). Photoelectron spectroscopy studies show that hydrated manganese oxide in the nanocomposite exists in the mixed Mn(II) to Mn(IV) oxidation states. Accordingly, chemical structures of MnO 2 and PPy constituents in the nanocomposite are not influenced by the co-deposition process. The MnO 2/PPy nanocomposite electrode material however shows significantly improved high specific capacitity, charge–discharge stability and the redox performance properties suitable for application in the high energy density supercapcitors.