Scientists have made a shocking discovery: common ice can generate electricity when bent. This breakthrough could explain lightning and inspire new technologies
Scientists Discover Ice Can Generate Electricity When Bent
In a discovery that could reshape our fundamental understanding of one of Earth's most common and essential substances, an international team of scientists has found that ordinary ice can generate electricity when it is bent, twisted, or subjected to uneven deformation. This hidden and surprising property, known as flexoelectricity, reveals that frozen water is not the simple, passive material it appears to be, but rather an active substance with fascinating and previously unknown electromechanical capabilities. The groundbreaking finding, which was recently published in the prestigious scientific journal Nature Physics, has major implications for future technological development and may finally shed light on the long-standing and powerful mystery of how lightning forms within thunderstorms.
The pivotal research was a collaborative international effort, co-led by the prestigious Catalan Institute of Nanoscience and Nanotechnology (ICN2), located at the UAB campus in Spain, alongside researchers from Xi’an Jiaotong University in China and Stony Brook University in New York. For many years, scientists have been puzzled by the apparent contradictions in ice's electrical behavior. It was a well-established fact that ice is not piezoelectric, a property that allows many crystalline materials to generate an electric charge when they are uniformly compressed. Since the polarized water molecules in an ice crystal typically cancel each other out, simple compression shouldn't produce electricity. Yet, in the natural world, it is a known fact that collisions between countless ice particles high up in clouds are responsible for creating the massive electrical charge separation that ultimately leads to lightning. This new study compellingly suggests that flexoelectricity is the long-sought-after missing piece of this atmospheric puzzle.
Unlike piezoelectricity, which is limited to materials with a certain type of crystal symmetry, flexoelectricity can occur in a much broader range of materials. It is defined as the generation of electricity in response to an inhomogeneous, or uneven, mechanical deformation, such as bending or twisting. To test this property in ice, the research team designed a meticulous experiment. They placed a slab of ice between two metal plates, which acted as electrodes, and carefully bent it. As they applied this uneven stress to the ice block, they measured a significant and consistent electric potential being generated. This act of careful measurement confirmed for the first time that ice is indeed a flexoelectric material at all tested temperatures, ranging from just below freezing to very low temperatures.
ICREA Professor Gustau Catalán, the leader of the Oxide Nanophysics Group at ICN2, explained the profound connection between their lab results and natural phenomena. He noted that the electrical potentials they generated by bending ice in the laboratory closely match the types of electrical potentials that have been previously observed during real-world ice-particle collisions in thunderstorms. This powerful correlation suggests that as ice crystals are tossed about in turbulent storm clouds, where they collide, bend, and deform irregularly, they could generate the initial electrical charge that builds up over a vast area and is eventually released as a bolt of lightning. The simple act of deforming ice on a massive scale could be a key mechanism in the electrification of clouds.
As if this discovery were not significant enough, the study also yielded another completely surprising finding. The team found that at extremely low temperatures, specifically below -113°C (160 Kelvin), a thin and previously undetected "ferroelectric" layer forms on the surface of the ice. Ferroelectricity is a property where a material can exhibit a spontaneous electric polarization, much like a tiny magnet has north and south poles. Crucially, this polarization can be reversed by applying an external electric field. This surface ferroelectricity is a remarkable discovery in its own right.
Dr. Xin Wen, a lead researcher on the study and a member of the ICN2 Oxide Nanophysics Group, highlighted the unique significance of this dual electrical behavior. "Ice may have not just one way to generate electricity but two: ferroelectricity at very low temperatures, and flexoelectricity at higher temperatures, all the way to 0 °C," he explained in a press release. This unexpected discovery places common ice in the same category as highly specialized, advanced electroceramic materials, such as titanium dioxide, which are currently essential components in modern technologies like sensors, capacitors, and memory devices.
This new and far more complex understanding of ice as an active electromechanical material opens up a host of exciting future possibilities. The researchers are already exploring new lines of investigation aimed at harnessing these unique properties for real-world, practical applications. While it is still in the very early stages of exploration, this discovery could pave the way for the development of entirely new classes of electronic devices that use ice as an active and functional component. Such technologies could be particularly useful for devices that need to be fabricated or operated in extremely cold environments, such as on polar expeditions or in space exploration. The finding fundamentally changes how we view one of the most ubiquitous materials on our planet, revealing that there are still profound and electrifying secrets hidden within a simple piece of frozen water.
What is Flexoelectricity?
Imagine you have a special kind of sponge. Normally, it does nothing, but if you bend or twist it, a tiny light bulb attached to it suddenly flickers on. This is the basic idea behind flexoelectricity. It’s a hidden property in some materials where they can generate electricity when you apply an uneven force, like bending them, instead of just squeezing them straight down.
Think of it this way: some materials create electricity when you squeeze them evenly—that’s called piezoelectricity. But flexoelectricity is different. It’s like the material only creates power when it's stretched on one side and squished on the other at the same time, which is exactly what happens when you bend something. This uneven pressure is the key that unlocks its electrical power.
So, when scientists say ice is flexoelectric, they mean that this very common material has a superpower nobody noticed before. The simple act of bending an ice crystal can cause it to produce a small amount of electricity. This discovery is exciting because it shows that even everyday materials have amazing properties and could be a clue to understanding natural wonders like lightning.