Engineers from the UC-San Diego Jacobs School of Engineering have developed stretchable biofuel cells that harvest energy from your sweat.
The engineers built the stretchable foundation using lithography and screen-printing to make 3D carbon nanotube-based cathode and anode arrays.
The cells are made with an enzyme that oxidizes the lactic acid in your sweat to generate current. Now, how much power? Well, the cells were connected to a circuit board that powered an LED for a total of four minutes while a researcher rode a stationary bike.
According to the researchers, the cells can generate 10 times the amount of power per surface area than an existing wearable cell. As for the amount of power, well, I’ll just redirect you once again to the size of the LED.
It’s one of two areas that the researchers plan to address next. Part of the reason that the LED was only lit for four minutes is that the concentration of lactic acid in a person's sweat gets diluted over time. Also, some people just sweat less than others. So, the team is looking for a way to store the energy produced while the concentration of lactate is high, and then release it gradually.
Because the silver oxide used at the cathode is light sensitive, it degrades over time, and the researchers are also looking for a more stable material to use.