Microbial fuel cells (MFCs) have emerged as a potential renewable energy source due to their ability for direct conversion of organic substrates into electrical energy. However, the practical application of this technology is hindered by low power density, limited long-term stability, and high operational costs. More specifically, one main factor impacting fuel cell performance is the bacterial interactions at the electrode interface and the associated electron transfer mechanisms. In an effort to increase productive interactions between the microbes and anode, this work focused on the synthetic design of a cellulose-based, nanocomposite material. The biomimetic electrode surface was modified via non-covalent linkages of organic fuels, such as glucose and lactate, with TiO2 nanoparticles to decrease bacteria-surface repulsions. Additionally, incorporation of β-cyclodextrin (β-CD), a supramolecular amphiphilic molecule, was used to constrain mediator adsorption to the surface of the cellulose matrix. The synergistic relationship between additives was investigated to modulate bacteria and mediator interactions at the electrode interface to ultimately increase the electron transfer efficiency. When compared to the industry standard carbon cloth materials, the composite electrodes had improved electrical response characterized via power density, polarization, and cyclic voltammetry for both E. coli and S. oneidensis MFC systems. Electrical output and bacteria-surface interactions were correlated using atomic force microscopy (AFM) and epifluorescent optical microscopy to determine biofilm formation and cell viability. Initial results show that the sugar functionalized electrodes demonstrated an increased electric response in conjunction with photochemical activity. This phenomenon was observed through decreased fluorescence intensity without a decrease in cell viability as well as increased open circuit potential in the presence of light. This ligand-metal charge transfer coupled with increased conductivity of a biomimetic bulk material has resulted in an overall improved MFC system.

Synthesis and design of biomimetic conductive nanocomposites to enhance key surface adsorption phenomena in microbial fuel cells

2019 Spring National Meeting

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