Check out the world’s smallest fuel cell. You can see it on the right; it's dimensions are only 3 mm x 3 mm x 1 mm. Researchers at the University of Illinois have done all the work for the development of this high tech fuel cell, that consists of just a few materials: water, metal hydride, some electrodes and a membrane.
The cell you see makes 0.7 volts and a 0.1 milliamp current and runs for about 30 hours, which is pretty long given the size of the cell. You can imagine that 0.7 volts and 0.1 milliamp current are not enough to power any high tech gadget of yours, however this is the first step in development.
The technology is good for mobile electronics such as smart phones since it does not use gravity to control the flow of water. Instead it uses surface tension and will work to charge when the device is moving.