You may charge your mobile by sand very soon. One of Grad. Student Zachary Favors of California has claimed that battery will be charged if you insert mobile into seashore sand. There is plenty amount of silicon in sand which is very effective to charge lithium-ion battery. A crucial part of lithium-ion batteries is graphite, but silicon has been said to potentially be a much better way to store energy.
They’ve already developed the prototype battery and say it has the potential to keep a mobile phone charged three times as long as it is now. They’ve also filed patents for the technology.