Ice is not as passive as it looks. New research shows that ordinary ice can create electricity when it is bent, stretched, or twisted. This unusual ability, known as flexoelectricity, means that even something as common as ice cubes in your drink has hidden electromechanical properties.
The research involved Institut Catala de Nanociencia I Nanotecnologia (ICN2) at the UAB campus, Xi’an Jiaotong University, and Stony Brook University.
The discovery reveals that ice’s electric behavior also changes with temperature. This finding could reshape how scientists understand one of the most familiar materials on Earth.
“The paper changes how we view ice: from a passive material to an active material that may be at play for both fundamentals and applications,” said Xin Wen, lead author and nanophysicist at ICN2 in Spain, as reported by Gizmodo.
Why ice confused scientists
For years, scientists wondered why ice was not piezoelectric. Piezoelectricity is the generation of electric charge when stress changes a material’s polarity. Water molecules are polarized, but when they form an ice crystal, their dipoles cancel each other out. That means ice should not produce electricity this way.
And yet, ice in nature does create electricity. For example, lightning in thunderstorms often results from collisions between charged ice particles. This mystery puzzled scientists because ice was not supposed to behave like that.
“Despite the ongoing interest and large body of knowledge on ice, new phases and anomalous properties continue to be discovered,” the researchers wrote in their paper. They added that this gap in understanding suggests “our understanding of this ubiquitous material is incomplete.”
How the experiment worked
The research team tested another form of electricity: flexoelectricity. Unlike piezoelectricity, flexoelectricity can occur in materials of any symmetry. This made it a strong candidate to explain ice’s unusual behavior.
In their experiment, scientists placed a slab of ice between two electrodes. They checked carefully to ensure that any electric charge produced was not piezoelectric. When they bent the slab, it generated electricity at every temperature tested.
“During our research, the electric potential generated by bending a slab of ice was measured. Specifically, the block was placed between two metal plates and connected to a measuring device. The results match those previously observed in ice-particle collisions in thunderstorms”, explained ICREA Prof. Gustau Catalán, leader of the Oxide Nanophysics Group at ICN2.
The team also made a surprising discovery. At extremely low temperatures, below -171.4 degrees Fahrenheit (-113 degrees Celsius), a thin ferroelectric layer appeared at the surface of the ice.
“This means that the ice surface can develop a natural electric polarization, which can be reversed when an external electric field is applied—similar to how the poles of a magnet can be flipped,” Wen noted in the press release.
Even more intriguing, he further added, “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 [degrees C].”
Why it matters
The results put ice in the same category as advanced electroceramic materials, such as titanium dioxide, which are widely used in technologies like sensors and capacitors. The ability to “flip” between flexoelectricity and ferroelectricity shows that ice is more versatile than expected.
The findings may also explain natural phenomena. The researchers noted that the electric potential they observed closely matched the energy produced by colliding ice particles in thunderstorms. This suggests that flexoelectricity could help drive how ice behaves inside storm clouds.
“With this new knowledge of ice, we will revisit ice-related processes in nature to find if there is any other profound consequence of ice flexoelectricity that has been overlooked all the way,” Wen told Gizmodo.
The team emphasized that more study is needed before drawing firm conclusions. But the discovery reveals that even a material as common as ice hides surprising complexities. What once seemed inert may actually be an active player in both technology and nature.
The study was published in the journal Nature Physics.