title: Microbial battery for efficient energy recovery.
abstract: By harnessing the oxidative power of microorganisms, energy can be recovered from reservoirs of less-concentrated organic matter, such as marine sediment, wastewater, and waste biomass. Left unmanaged, these reservoirs can become eutrophic dead zones and sites of greenhouse gas generation. Here, we introduce a unique means of energy recovery from these reservoirs-a microbial battery (MB) consisting of an anode colonized by microorganisms and a reoxidizable solid-state cathode. The MB has a single-chamber configuration and does not contain ion-exchange membranes. Bench-scale MB prototypes were constructed from commercially available materials using glucose or domestic wastewater as electron donor and silver oxide as a coupled solid-state oxidant electrode. The MB achieved an efficiency of electrical energy conversion of 49% based on the combustion enthalpy of the organic matter consumed or 44% based on the organic matter added. Electrochemical reoxidation of the solid-state electrode decreased net efficiency to about 30%. This net efficiency of energy recovery (unoptimized) is comparable to methane fermentation with combined heat and power.
authors.affiliation: Departments of Civil and Environmental Engineering, Materials Science and Engineering, and Chemistry, Stanford University, Stanford, CA 94305.
authors.forename: Xing
authors.initials: X
authors.lastname: Xie
authors.forename: Meng
authors.initials: M
authors.lastname: Ye
authors.forename: Po-Chun
authors.initials: PC
authors.lastname: Hsu
authors.forename: Nian
authors.initials: N
authors.lastname: Liu
authors.forename: Craig S
authors.initials: CS
authors.lastname: Criddle
authors.forename: Yi
authors.initials: Y
authors.lastname: Cui
mesh_terms: D001674:Bioelectric Energy Sources; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes / Q000382:microbiology*; D004583:Electrons; D009930:Organic Chemicals / Q000378:metabolism*; D010084:Oxidation-Reduction; D010087:Oxides; D018030:Silver Compounds; D062065:Wastewater / Q000737:chemistry*
chemical_list: D009930:Organic Chemicals; D010087:Oxides; D018030:Silver Compounds; D062065:Wastewater; C040225:disilver oxide
keywords: bioelectrochemical system; exoelectrogens; microbial fuel cells; renewable energy
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