The University of Texas at Dallas has developed a nanotube-based tissue capable of generating energy from the movements of the human chest during breathing. It consists of twisted carbon fibers and is called the "twistron". The physical mechanism of its operation is surprisingly simple.
If we weave a kind of twisted rope out of nanotubes, then it will tend to restore its shape when the external twisting effect stops. If we now moisten it with electrolyte, then with any deformation of the fiber, this coating will be divided into areas with a positive and negative charge, between which an electric current will begin to flow.
During such deformation-recovery, a small amount of mechanical energy is converted into electrical energy. And if the first is difficult to use effectively with such an amount, then electricity can be stored in the battery. As an example, consider a balloon to which a weight is suspended on a 10-centimeter twistron thread. Straightening under its weight, the filament generates 1.79 microwatts per milligram of its mass - potentially, this free energy can power small wearable electronics. In comparison, if you scale up the system to 1 kilogram of tissue and make it vibrate at a rate of 30 vibrations per second, it will generate 250 watts of electricity. This is enough to power a desktop computer, for example.
At the moment, the technology for creating a twistron fabric is rather complicated and expensive. However, its potential to harvest free energy from any movement could revolutionize, for example, the Internet of Things. Pieces of twistronic cloth can harvest the energy of ocean waves to power communication buoys, and clothing with nanofiber inserts can power sensors or small gadgets.