Electroactive polymers have been shown to be efficient energy conversion and storage materials.[1] In particular, organometallics and their derivatized metallopolymers have been attractive platforms due to their tunable Faradaic processes based on ligand and metal design. Here, we present an asymmetric pseudocapacitor system composed of redox-polymers for enhanced energy storage and electrochemistry in water.[2] Undesirable side-reactions at the interface of electrodes, especially the cathode, are economically and energetically costly, since they affect the materials' stability and drain current density that could otherwise be applied to an useful process (e.g. charge storage, sensing or catalysis). A series of organometallics (including bipyridines, metallocenes and metal cyanides) were immobilized on the cathode and studied based on their energy storage and ability to suppress water reduction. A poly(vinyl)ferrocene (PVF)-nanotube (CNT) anode,[3] when combined with the screened cathodes, was shown to result in more efficient electrochemical cell design when in an asymmetric arrangement. When the poly(vinyl)ferrocene anode was combined with a cobaltocenium-containing polymer (PMAECoCp2+PF6-)[4] counter, the cell could sustain current densities up to 8 A/cm2 yet maintaing low overpotentials for the anode and completely suppressing any side-reactions. The ferrocene/cobaltocenium system also showed a dramatically increased electrochemical capacitance of the asymmetric arrangement over the symmetric (498 F/g vs 296 F/g) due to favorable electron-transfer kinetics. Thus, these asymmetric pseudocapacitors composed of redox-polymers are not only promising for energy storage, but in controlling water-chemistry in electrochemical processes in general. [1] a) Hou, et al. W. J of Mat Chem A 2014, 2, 10910. b) Simon, P.; Gogotsi, Y. Nat Mat 2008, 7, 845. [2] Su, X.; Tan, K.J.; Thomas, J.; Jamison, T.F.; Hatton, T. A. Energy and Env Sci. 2015. Under Review. [3] Mao, X. W.; et al. J of Mat Chem A, 2013, 1, 13120-13127. [4] Ren, L. X.; et al. J Am Chem Soc, 2010, 132, 8874-+.

Organometallics polymers as asymmetric pseudocapacitors: Molecular tuning of redox-electrodes for enhanced energy storage and controlled water chemistry

251st National Meeting (2016)

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