Graphene‐Based Flexible Micrometer‐Sized Microbial Fuel Cell

Abstract

Microbial fuel cells harvest electrical energy produced by bacteria during the natural decomposition of organic matter. We report a micrometer‐sized microbial fuel cell that is able to generate nanowatt‐scale power from microliters of liquids. The sustainable design is comprised of a graphene anode, an air cathode, and a polymer‐based substrate platform for flexibility. The graphene layer was grown on a nickel thin film by using chemical vapor deposition at atmospheric pressure. Our demonstration provides a low‐cost option to generate useful power for lab‐on‐chip applications and could be promising to rapidly screen and scale up microbial fuel cells for water purification without consuming excessive power (unlike other water treatment technologies).

Applications of Graphene-Modified Electrodes in Microbial Fuel Cells

“…The main substrates used in graphene production are transition metal materials, e.g., Cu [72] and Ni [7]. The graphene films obtained can be transferred to other substrates, maintaining their excellent conductivity and transmittance.…”

“…Chemical vapor deposition (CVD) is a widely applied technique for manufacturing semiconductor films, where the chemical reaction of a carbon source (e.g., methane [ 69 ], ethanol [ 70 ], and cyanuric chloride [ 71 ]) is conducted in a high-temperature, high gas flow rate condition and the resultant film is deposited on the surface of a heated solid substrate. The main substrates used in graphene production are transition metal materials, e.g., Cu [ 72 ] and Ni [ 7 ]. The graphene films obtained can be transferred to other substrates, maintaining their excellent conductivity and transmittance.…”

“…The microbial fuel cell (MFC) is a promising recently developed device that can convert the chemical energy stored in organic fuels as nutritional substrates into electrical energy though the metabolism of microorganisms, while degrading the organic contaminant to an extent [ 3 , 4 , 5 ]. Compared with traditional chemical fuel cells [ 6 ], large-scale organic substrates, such as municipal treatment plants [ 7 , 8 ], agriculture wastes, solid wastes from dairy farms [ 9 , 10 , 11 , 12 ], and even human waste [ 13 , 14 ], can be used as fuels in MFCs. However, many factors affect the performance of MFCs, including the chemical substrate, ionic concentration, proton exchange material, catalyst, internal resistance, electrode spacing, and electrode materials [ 15 , 16 , 17 , 18 , 19 , 20 ].…”

Carbon‐Based Microbial‐Fuel‐Cell Electrodes: From Conductive Supports to Active Catalysts

“…The rise of graphene within the recent years had of course also an impact on the research of carbon‐material‐based MFC. Graphene and its derivatives (graphene oxide (GO), reduced graphene oxide (r‐GO), functionalized graphene and so on), exhibit outstanding chemical and physical properties, including mechanical robustness, good electron conductivity, high surface area and suitable bioadhesive properties, which make them highly promising candidates for anodes in MFCs . Initially, r‐GO‐modified carbon‐cloth electrodes were studied and it was shown that the anodes biofilm formation and conductivity was increased after the modification with r‐GO .…”

Application of Graphene‐Based Materials to Improve Electrode Performance in Microbial Fuel Cells

“…Instead of using the physical coating method, Liu and coworkers [18] adopted an electrochemical method, in which GO was electrophoretically transported to the surface of a carbon cloth (CC) electrode in a two-electrode cell under 0.3 mA cm −2 anodic current and then reduced to GNSs under 0.6 mA cm −2 cathodic current; in that way, they determined the optimal deposition time that gave the best performance of the MFC. wastewater, indicating the potential application of GNSs for lab-on-a-chip MFC devices [26]. As a typical flat-sheet material, GNSs applied to an anode electrode tend to stack as a result of the strong van der Waals attraction between the sheets during the coating process, thereby compromising their high accessible surface area.…”