Energy harvesting from organic liquids in micro-sized microbial fuel cells

Abstract

Micro-sized microbial fuel cells (MFCs) are miniature energy harvesters that use bacteria to convert biomass from liquids into usable power. The key challenge is transitioning laboratory test beds into devices capable of producing high power using readily available fuel sources. Here, we present a pragmatic step toward advancing MFC applications through the fabrication of a uniquely mobile and inexpensive micro-sized device that can be fueled with human saliva. The 25-ll MFC was fabricated with graphene, a two-dimensional atomic crystal-structured material, as an anode for efficient current generation and with an air cathode for enabling the use of the oxygen present in air, making its operation completely mobile and free of the need for laboratory chemicals. With saliva as a fuel, the device produced higher current densities (1190 A m À3 ) than any previous aircathode micro-sized MFCs. The use of the graphene anode generated 40 times more power than that possible using a carbon cloth anode. Additional tests were performed using acetate, a conventional organic material, at high organic loadings that were comparable to those in saliva, and the results demonstrated a linear relationship between the organic loading and current. These findings open the door to saliva-powered applications of this fuel cell technology for Lab-on-a-Chip devices or portable point-of-care diagnostic devices.

Urine-activated origami microbial fuel cells to signal proof of life

“…Chemical paperbased fuel cells rely on the addition of liquid to activate chemicals e.g. Recent work has also reported MFCs fed with saliva, 30 and this can only help in promoting the MFCs in this technology niche/sector. 7 Such systems can generate a signicant burst of power using indiscriminate liquids where for example the use of either urine or water will give the same result.…”

Integrated Microfluidic Flow-Through Microbial Fuel Cells

“…Generally, μMFCs are featured by low material consumption, short start-up time, easy operation, and experiment parallelization13. To improve current and power densities of μMFCs, researchers have made significant progress in optimizing bacterial strains16172122, device structures181920242526, and anode materials232425262728293031323334353637383940414243444546. For example, due to the large surface area-to-volume ratio, many micro/nanomaterials have been developed as anode materials of μMFCs to promote bacterial attachment and colonization, and electrochemical catalytic activity of anodes, such as carbon nanotubes (CNTs)23284344, graphene45, graphene-based nanocomposites272930, poly(3,4-ethylenedioxy-thiophene) (PEDOT)313246, and PEDOT-based nanocomposites343536373839404142.…”

Microbial Fuel Cells as Alternate Source of Energy: Research, Advancements and Future Prospects in Indian Scenario

“…For instance, glass wafers sputtered with Cr and Au in micronscale proved to be ideal for rapid onset of current generation [36]. Some other modified electrodes recently reported are multiwalled carbon nanotubes [19] and their composites [29] and multilayered graphene foil [37]. Graphene and graphene based compounds have proven to be good choices for anodes in enzymebased biofuel cells too, due to its excellent electrical communication properties as redox active conducting polymers [38].…”