A μL-scale micromachined microbial fuel cell having high power density

Abstract

We report a MEMS (Micro-Electro-Mechanical Systems)-based microbial fuel cell (MFC) that produces a high power density. The MFC features 4.5-μL anode/cathode chambers defined by 20-μm-thick photo-definable polydimethylsiloxane (PDMS) films. The MFC uses a Geobacter-enriched mixed bacterial culture, anode-respiring bacteria (ARB) that produces a conductive biofilm matrix. The MEMS MFC generated a maximum current density of 16,000 μA cm(-3) (33 μA cm(-2)) and power density of 2300 μW cm(-3) (4.7 μW cm(-2)), both of which are substantially greater than achieved by previous MEMS MFCs. The coulombic efficiency of the MEMS MFC was at least 31%, by far the highest value among reported MEMS MFCs. The performance improvements came from using highly efficient ARB, minimizing the impact of oxygen intrusion to the anode chamber, having a large specific surface area that led to low internal resistance.

Use of a Coculture To Enable Current Production by Geobacter sulfurreducens

“…There are other findings which similarly suggest that oxygen leakage into an MFC reduces power generation by pure cultures. Choi et al (8) found that power generation by G. sulfurreducens was enhanced when L-cystine (a chemical oxygen scavenger) was added into a microsized MFC (ferricyanide catholyte). While oxygen leakage through the cathode is well known (6,7,16,17), Yang et al (30) have shown that there is substantial oxygen leakage through the gaskets and septa used in these single-chamber, cubetype MFCs used in many studies (11,12,16,17,28).…”

Boosting Power Density of Microbial Fuel Cells with 3D Nitrogen‐Doped Graphene Aerogel Electrode

“…In addition, the maximum areal power density (normalized to the geometric surface area of N‐GA, 9.4 cm 2 ) for N‐GA MFC is 1990.8 ± 106.1 mW m −2 , which is much higher than the values of CC MFC (78.2 ± 2.7 mW m −2 ) and rGO‐Ni MFC (517.6 ± 8.0 mW m −2 ). Significantly, the maximum areal power density is also among the state‐of‐the‐art performance and considerably higher than other MFCs with carbon‐based bioanodes, including the MEMS MFC (47 mW m −2 ),23 carbon nanotube‐based MFC (830 ± 10 mW m −2 )24 and graphene/PANI foam‐based MFC (768 mW m −2 ) 25. From the polarization curves shown in Figure 3b, the N‐GA MFC also exhibited the highest open circuit potential (0.69 ± 0.01 V) with the largest maximum current (20.50 ± 0.35 mA) among the three MFCs.…”

A miniaturized parallel analyses platform for rapid electrochemical discoveries of microbial activities

“…Shewanella oneidensis uses a solid component (known as nanowire) in the biofilm matrix that is conductive for electron transfer between the microbes and the electrode while Pseudomonas aeruginosa produces soluble electron shuttle that uses diffusive transport to carry electrons from the bacteria to the electrode. Therefore, Pseudomonas aeruginosa cannot produce high current density, because the diffusion rates of the mediators significantly limit the rate of EET by diffusion [10,11].…”