Bending ice generates electricity

We have discovered that, when ice is bent, it generates electricity.How much electricity depends on the amount of bending (of course) and the purity of the ice. Ice is not very flexible, but inducing large deformations (and therefore large electric signals) is possible at small lengthscales. Thus, we have shown that the small deformations that happen when ice particles collide with each other inside storm clouds can generate enough voltage to eventually trigger lightning, thus providing a possible answer to the centuries-old question about how the electricity is generated inside storm clouds. As for the effect of purity, we find that impurities can be good. Specifically, adding salt to ice increases by several orders of magnitude the electrical currents it can generate in response to bending, to the point that its electromechanical performance becomes comparable with that of good piezoelectric materials.The consequences of these discoveries are manifold. On the practical front, being able to generate electricity with ice is appealing, but has the drawback of course that ice can only exist in cold places. While this may still make it usable in polar regions and/or planetary exploration, we think that the practical angle may come not from ice itself, but from the mechanism behind its ability to generate large electric currents, which we call "streaming flexoelectricity" and we show that it could be present in any porous material infused with brine. But the more exciting angle is the fundamental one: ice is everywhere, from clouds to mountains to polar regions. Even beyond Earth it covers the surface of other planetary objects, such as some moons of Jupiter, where life is thought to be possible. What our research shows is that any inhomogeneous deformation (fractures, collisions etc) in these scenarios can generate electrical discharges, thus providing a source of energy to power natural phenomena -of which lightning is just one example.