Supercapacitors Based on c-Type Cytochromes Using Conductive Nanostructured Networks of Living Bacteria

Authors

  • Dr. Nikhil S. Malvankar,

    Corresponding author
    1. Department of Physics, University of Massachusetts, Amherst, 203, Morrill Science Center IVN, 639 North Pleasant Street, Amherst, MA 01003 (USA), Fax: (+1) 413-577-4660
    2. Department of Microbiology, University of Massachusetts, Amherst (USA)
    • Department of Physics, University of Massachusetts, Amherst, 203, Morrill Science Center IVN, 639 North Pleasant Street, Amherst, MA 01003 (USA), Fax: (+1) 413-577-4660
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  • Dr. Tünde Mester,

    1. Department of Microbiology, University of Massachusetts, Amherst (USA)
    2. Current address: University of Michigan Medical School and Veterans Affairs Medical Research Center, Ann Arbor, Michigan 48105, USA.
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  • Prof. Mark T. Tuominen,

    1. Department of Physics, University of Massachusetts, Amherst, 203, Morrill Science Center IVN, 639 North Pleasant Street, Amherst, MA 01003 (USA), Fax: (+1) 413-577-4660
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  • Prof. Derek R. Lovley

    1. Department of Microbiology, University of Massachusetts, Amherst (USA)
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Abstract

Supercapacitors have attracted interest in energy storage because they have the potential to complement or replace batteries. Here, we report that c-type cytochromes, naturally immersed in a living, electrically conductive microbial biofilm, greatly enhance the device capacitance by over two orders of magnitude. We employ genetic engineering, protein unfolding and Nernstian modeling for in vivo demonstration of charge storage capacity of c-type cytochromes and perform electrochemical impedance spectroscopy, cyclic voltammetry and charge–discharge cycling to confirm the pseudocapacitive, redox nature of biofilm capacitance. The biofilms also show low self-discharge and good charge/discharge reversibility. The superior electrochemical performance of the biofilm is related to its high abundance of cytochromes, providing large electron storage capacity, its nanostructured network with metallic-like conductivity, and its porous architecture with hydrous nature, offering prospects for future low cost and environmentally sustainable energy storage devices.

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