They design biofuel cells that get energy from sweat

[OyaYansa]

A team of engineers at the University of California, San Diego (USA) has developed elastic fuel cells that stick to the skin with the ability to produce energy from sweat. Harvested electricity can be used to power some low-consumption portable electronic devices such as LED lights or Bluetooth radios, among other examples.

The epidermal cells that have designed these researchers stand out for having the capacity to generate 10 times more power per surface than any other existing biofuel cell. For their development they have combined intelligent chemistry, advanced materials and electronic interfaces, which has allowed them to manufacture an elastic electronic base through the use of lithography and screen printing to accommodate the anode and the cathode.

The device is composed of rows of points which are connected by spring-like structures. Half of the dots form the anode of the cell, while the other half are the cathode. The base of the structure is made of gold with lithography, on which the layers of biofuels are deposited at the top of the anode points, loaded with enzymes that react to the lactic acid of the sweat, and the cathode with oxide silver. The spring-like structures stretch and bend without problem, which makes it possible for the cells to be completely flexible without deforming the anode and the cathode.

To increase the power density of the device, these engineers printed a 3D carbon nanotube structure at the top of the anode and cathode, which allows each point to be charged with more of the enzyme that reacts to lactic acid in the case of the anode And to the silver oxide in the cathode. Nanotubes also have the advantage of facilitating electron transfer, a feature that optimizes the performance of fuel cells.

To prove their effectiveness, the researchers connected the cells to a custom-made circuit board and attached them to the skin of a person who was exercising on a static bicycle. The device was able to provide the power needed to activate an LED for four minutes.

Now, the team wants to replace the silver oxide of the cathode and replace it with a more stable material, as well as optimizing other issues of energy storage.