A Short Overview of Biological Fuel Cells

Abstract

This short review summarizes the improvements on biological fuel cells (BioFCs) with or without ionomer separation membrane. After a general introduction about the main challenges of modern energy management, BioFCs are presented including microbial fuel cells (MFCs) and enzymatic fuel cells (EFCs). The benefits of BioFCs include the capability to derive energy from waste-water and organic matter, the possibility to use bacteria or enzymes to replace expensive catalysts such as platinum, the high selectivity of the electrode reactions that allow working with less complicated systems, without the need for high purification, and the lower environmental impact. In comparison with classical FCs and given their lower electrochemical performances, BioFCs have, up to now, only found niche applications with low power needs, but they could become a green solution in the perspective of sustainable development and the circular economy. Ion exchange membranes for utilization in BioFCs are discussed in the final section of the review: they include perfluorinated proton exchange membranes but also aromatic polymers grafted with proton or anion exchange groups.

Bioenergy‐Based Closed‐Loop Medical Systems for the Integration of Treatment, Monitoring, and Feedback

“…[123] BFCs are classified by electron transfer pathways into mediated electron transfer cells and direct electron transfer cells. [14] In practice, BFCs can noninvasively harvest biochemical energy from biological fluids such as sweat, saliva, interstitial fluid, and tears; [124] the fluid provides the electrolyte (e.g., glucose, [125] lactic acid, [126] and ethanol) [107,127] that fuels power generation (Figure 5a). [108] A BFC that harvests chemical energy from the finger sweat of a 2 cm 2 area can collect hundreds of millijoules of energy during sleep.…”

“…A tattoo‐based electrochemical sensor can extract biological fluids via reverse ion import. [ 14 ] A device using microfluidic storage can minimize direct skin contact and sample evaporation in glucose and lactic acid sensors, [ 111 ] with the microfluidic channels providing rapid sampling and efficient analyte transport through the sensing electrodes. Wearable microfluidic device design must also consider stretchability and ductility.…”

“…Biofuel cells (BFCs) are commonly used to harvest bioenergy via enzymatic reactions [ 14 ] that utilize the remarkable specificity of enzyme‐substrate interactions and generate reaction products in proportion to the substrate concentration. [ 110 ] Unlike traditional rigid energy storage systems (rechargeable batteries and supercapacitors), [ 122 ] wearable BFCs generate green electricity from energy‐dense, carbon‐neutral fuels via efficient bioelectrochemical reactions; lactate and glucose are two of the most common substrates.…”

“…Biomechanical energy can be scavenged from the soles of the feet, knees, ankles, wrists, the vibrations of organs, and other highly mobile areas. [ 13 ] Biochemical energy can be harvested from sweat, tears, urine, and interstitial fluids, [ 14 ] while biothermal energy can be obtained from temperature differentials between the body and the environment or between different body parts. [ 15 ] This energy is largely wasted in daily life but might become useful for closed‐loop medical systems if wearable devices can harness these easily acquired and sustainable potential bioenergy sources.…”

Smartphone-Based Electrochemical Systems for Glucose Monitoring in Biofluids: A Review

“…The advantages of microbial fuel cells are high conversion efficiency and efficient operation at room temperature. The particularity of an enzymatic fuel cell is the replacement of bacteria with redox enzyme catalysts, with a considerable gain in volumetric catalytic activity, but at a substantially higher cost [ 118 ]. Jeerapan et al proposed a biofuel cell based on aa highly stretchable textile for the construction of self-powered devices for the monitoring of glucose and lactate [ 119 ].…”