We tend to think of ice as something ordinary: the cubes that cool our drinks, the frost on a winter morning, the immense glaciers carving valleys over millennia. Yet beneath its crystalline beauty lies a world of physics that is still revealing surprises. A new study, co-led by researchers at ICN2 (Institut Català de Nanociència i Nanotecnologia) and published in Nature Physics, has uncovered a remarkable property of ice: it is flexoelectric.
This means that ice can generate electricity when bent or unevenly deformed. It is not simply frozen water—it is a natural material with electromechanical abilities that bring it into the same class as advanced ceramics used in cutting-edge technologies. What we thought we knew about ice was only the surface; hidden within, it carries an unsuspected power.
Flexoelectricity: Electricity Born From Stress
Most people are familiar with piezoelectric materials, like quartz, that can generate electricity when squeezed or compressed. Flexoelectricity, however, is slightly different. It emerges not from simple pressure, but from uneven mechanical deformation—from bending, stretching, or twisting that disturbs the structure in irregular ways.
The new study shows that ordinary ice, the same substance that coats mountain peaks and fills our freezers, possesses this rare property. When scientists placed a block of ice between two metal plates and carefully bent it, they detected an electric potential being produced.
What makes this finding extraordinary is that it solves a long-standing puzzle about nature itself—how clouds become charged during thunderstorms.
Lightning in the Sky, Electricity in the Ice
Every thunderstorm holds a spectacular mystery. Lightning, a bolt of raw electricity that can heat the air hotter than the surface of the Sun, is born from collisions of ice particles inside clouds. These collisions somehow charge the cloud, building up an enormous potential that eventually discharges as lightning.
But for decades, scientists were left with a riddle: ice is not piezoelectric, so how does it become charged simply by colliding? The new research offers a breakthrough answer. Ice may not be piezoelectric, but it is flexoelectric. That means when ice particles in storm clouds collide and deform each other in irregular ways, they can indeed generate electric charges.
Flexoelectricity, then, may be the missing link in understanding one of Earth’s most powerful natural spectacles. Every flash of lightning could be, in part, the silent work of this hidden property of ice.
The Surprising Dual Nature of Ice
As if that weren’t enough, the study revealed another astonishing discovery: at extremely low temperatures—below -113ºC (160 K)—ice develops a thin surface layer that is ferroelectric. This means that the surface of the ice can carry a permanent electric polarization, which can be flipped by an external electric field, much like reversing the poles of a magnet.
This duality makes ice unique. At very low temperatures, it can act as a ferroelectric material. At higher, more common cold temperatures (all the way up to the melting point of 0ºC), it behaves as a flexoelectric material. Two distinct electrical phenomena, wrapped into the same humble crystal of frozen water.
In other words, ice has more than one way to make electricity. It is no longer just a passive substance in nature but an active participant in the drama of energy and charge.
From Glaciers to Gadgets: Technological Promise
The implications of this discovery go far beyond thunderstorms. Flexoelectric materials are highly sought after in modern technology. They are already used in advanced ceramics like titanium dioxide, which power sensors, capacitors, and energy-harvesting devices. That ice, one of the most abundant materials on Earth, shares this property opens up intriguing possibilities.
Imagine electronic devices built to function in extreme cold, using ice itself as an active component. Picture energy-harvesting systems in polar regions, where ice sheets flex and bend naturally under stress. Though still a distant vision, the possibility that frozen water might one day contribute to technology makes us rethink its role in our lives.
The Poetry of Discovery
There is something deeply poetic about this finding. Ice, a symbol of stillness and silence, turns out to harbor an invisible energy that sparks into electricity when disturbed. What seems frozen and lifeless is, in fact, a dynamic and responsive material with hidden vitality.
It also reminds us that nature’s most familiar substances—those we think we understand completely—still carry secrets waiting to be uncovered. Just as Galileo’s telescope revealed moons around Jupiter, and Darwin’s observations of finches unlocked the story of evolution, bending a slab of ice has revealed a new chapter in our understanding of the natural world.
A Step Into the Future
The study, conducted by ICN2 together with Xi’an Jiaotong University and Stony Brook University, represents more than just a scientific curiosity. It is a step forward in the electromechanical science of materials, and a reminder of how the simplest things can change the way we understand both technology and nature.
By uncovering the flexoelectric and ferroelectric properties of ice, researchers have expanded not only the scientific story of water but also our appreciation of how deeply intertwined the elements of Earth are with the phenomena we observe—from the sparkle of frost on a windowpane to the crackling power of a thunderstorm.
And so, the next time you see lightning split the sky, or hear the thunder roll through a storm, you might imagine the billions of tiny ice particles colliding high above you—not just as frozen water, but as microscopic generators of electricity, carrying within them the hidden power of flexoelectricity.
More information: X. Wen et al, Flexoelectricity and surface ferroelectricity of water ice, Nature Physics (2025). DOI: 10.1038/s41567-025-02995-6
