Scientists find ice generates electricity when bent, possibly explaining lightning

A group of researchers has discovered that ice is flexoelectric — it produces electricity when it is bent or unevenly deformed. The new discovery — published in the journal Nature Physics — represents a step forward in the understanding of ice, one of the most abundant substances on Earth, and could even explain lightning.

Scientists have known for a long time that lightning is generated by the collision of ice particles inside clouds. But without a clear explanation as to how those particles become electrically charged, because ice is not piezoelectric — it doesn't produce electrical charge from simple compression.

This new study demonstrates that the uneven deformation of ice during these collisions is enough to generate an electric charge. The researchers made calculations of the charge generated by this flexoelectric effect of ice, and it corresponded to the amount of charges known to be transferred in lightning events. This suggests it plays a key role in the electrification of clouds.

The study also found that at temperatures below −113 °C, a thin ferroelectric layer which can also generate an electric charge forms on the ice's surface. This puts it on the same level as advanced electroceramic materials like titanium dioxide. The researchers say this could lead to electronic materials that use ice as an active material.