Scientists at Virginia Tech in Blacksbur lead by Shashank Priya are experimenting with zinc oxide, which is known for its piezoelectric properties. It can convert physical pressure and vibration into energy, which could potentially recharge batteries. Experiments have shown that the method can deliver about 50 millivolts under favorable conditions.
Unfortunately, that is far from enough to power a handset continuously. However, in an emergency situation, a few minutes of shaking a phone might be sufficient to provide the energy needed to make an important phone call, according to the scientists.