Portable biofuel cells now produce electricity from lactic acid in sweat

By 14/04/2021 portal-3

Las células de biocombustible portátiles ahora producen electricidad a partir del ácido láctico del sudor

A team of scientists led by Associate Professor Isao Shitanda of Tokyo University of Science has just published A study describing a novel design for a biofuel cell array that uses a chemical in sweat, lactic acid, to generate enough energy to power a biosensor and wireless communication devices for a short period of time.

More power than previous designs

Their new biofuel cell matrix looks like a paper bandage that can be worn, for example, on the arm or forearm. It essentially consists of a water-repellent paper substrate on which multiple biofuel cells are placed in series and parallel; The number of cells depends on the output voltage and the power required.

In each cell, electrochemical reactions between lactic acid and an enzyme present on the electrodes produce an electric current, which flows into a general current collector made of a conductive carbon paste.

This not the first lactic acid-based biofuel cell, but a few key differences make this new design stand out. One is the fact that the entire device can be manufactured using screen printing, a technique generally suitable for cheap mass production. This was made possible by careful selection of materials and ingenious design. For example, while previous similar cells used silver wires as conductive paths, today's biofuel cells employ porous carbon ink.

Another advantage is the way lactic acid is delivered to the cells. The layers of paper are used to collect sweat and transport it to all cells simultaneously through the capillary effect, the same effect by which water travels quickly through a napkin when it comes into contact with a puddle of water.

They also transmit more energy: They could generate a voltage of 3.66 V and an output power of 4.3 mW.

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Portable biofuel cells now produce electricity from lactic acid in sweat

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Xataka Science

Sergio Parra