Biofuel cells that can use sweat to set the wearable devices working
Recently, a group of researchers has developed a band comprised of stretchable fuel cells. The stretchable fuel cells have the ability to extract energy from the sweat and power electronic devices such as Bluetooth radios, LEDs, and others. These biofuel cells produce about ten times more energy per surface area compared to any of the existing wearable biofuel cells. The cells can be used to power the wearable devices as well.
The use of epidermal biofuel cells is a huge breakthrough for the wearable and other electronics industry. The cells help generate a powerful and stretchable device. The researchers from the University of California have used a combination of chemistry, electronic interfaces, and advanced materials to achieve such a breakthrough. The stretchable and powerful electronic device was built using lithography and screen-printing to form 3D carbon nanotube-like anode and cathode arrays.
But how do the cells work? All that the biofuel cells do is to use an enzyme to oxidize the lactic acid present in the sweat and generate power. To prove the concept foolproof, the scientists attached the device to the skin of an individual, who was using the stationary bike to exercise. The biofuel cells were connected to a customized circuit board which later helped power an LED device. Thus, proving the worth and efficiency of the biofuel cells.
The biofuel cells have been designed based on the island and bridge structure wherein the biofuel cells are arranged in a row of dots and connected to each other by the spring-shaped structure. The row of dots is divided into anode and cathode. It is so stretchable and flexible that there are no chances of the array of anode and cathode being deformed. The basis for the overall structure is made using gold and manufactured by lithography. The screen-printing method helped deposit biofuel material on the array of anode and cathode.
The researchers enhanced the performance that is the energy generated per surface area by screen-printing the 3D carbon nanotube structures on the anode and cathode. The enzyme present on the anode dots helped react with lactic acid and silver oxide present on the cathode dots followed by the tubes that facilitated easy transfer of electrons for a better performance.
In the future, the scientists want to find an alternative for silver oxide that degrades over time and in presence of light. Also, the concentration of the lactic acid in the sweat dilutes over time. Thus, the alternative to all these problems will help develop a better performing biofuel cell that can power the electronics.