The power-generating sheet developed by Fujifilm and AIST could be used to provide additional power for portable devices.
The sheet uses the thermoelectric effect, which generates a voltages due to the temperature difference between the surface of an object and its reverse side. The sheet is 0.4mm thick and soft. In a normal environment, the temperature of the air is lower than that of the human body or the surface of clothes. That temperature difference can be used to generate a steady flow of electricity.