Stackable cow dung based microfabricated microbial fuel cells

μL-scale microbial fuel cell (μMFC) technology has the potential to serve as an efficient renewable energy harvester for a variety of applications ranging from, on chip devices to autonomous sensors in remote locations. However, low voltage and power outputs have restricted such microbial fuel cells (MFCs) from most practical applications. To bypass this limitation, we present a stackable microfabricated high-voltage cow dung-based μL-scale microbial fuel cell (CDFC) that utilizes a complex natural substrate (cow dung) and microstructures to attain higher voltages and power densities. Specifically utilizing micropillars which increased the electrode surface area 155 % compared to planar electrodes and a rich microbial consortium in the cow dung. Experimental results for the CDFC revealed open circuit potentials (OCPs) of 0.85±0.05 V, which represent the highest reported for a μMFC thus far. The CDFC was also found to produce power densities of 95±10 W/m3. By using two CDFCs stacked in series OCPs were increased by approximately 100%. These results suggest that the CDFC methodology represents a big step towards making μMFCs viable energy harvesters for both electronic and biological applications.