Bending ice creates electricity?

Newly discovered property of ice could lead to new technologies and understanding of natural phenomena

Despite being a relatively well-known material, ice still has many secrets yet to be discovered. One of these secrets that recently was uncovered by scientists from Xi'an Jiaotong University in China and Stony Brook University of New York. In an international study, these scientists discovered an extraordinary property of ice: it is flexoelectric and, at extremely low temperatures, is ferroelctric.

A material is flexoelectric if it is able to produce electric current when subjected to mechanical deformation, like bending. In an experiment, the scientists connected two metal plates on both sides of a slab of ice that was being bent unevenly. A measuring device confirmed the generation of an electrical current. What's more, at extremely low temperatures (-133 degress C, or 160 Kelvin), the scientists discovered a thin ferroelectric layer at the surface of the ice. Ferroelectric means that a material spontaneously develops an electrical polarization: the dipoles (tiny positive-negative differences, e.g compounds such as H2O can become electrically polarized when one side's probability of having electrons is greater than the other side, resulting in one side being slight positive while the other is slight negative) within the material align in a particular direction without any external electric field. Importantly, this electric polarization can be reversed, or flipped, with the application of an external electric field. Interestingly, this reversibility can be used as yet another way of generating electricity, but only at very low temperatures.

What's even cooler is how this discovery sheds light on a particular natural phenomena: lighting. It is understood that lighting comes from collisions between ice particles in clouds, which builds up electric charge in the ice, leading to electric potential in the clouds that is released through lightning. However, it since ice is not piezoelectric (able to generate charge from compression) at those temperatures, the inner workings of this were still unknown. This new discovery directly explains this, showing that ice can generate electrical charge through inhomogeneous deformation. Furthermore, from a more technical aspect, this discovery could eventually lead to the development of electronics that utilize ice directly, enabling them to be created in and better perform in cold environments.

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