Scientists uncover bizarre new material that's breaking one of the laws of this Universe

Scientists from the University of Chicago and UC San Diego have discovered a group of materials that behave in surprising ways when put under heat, pressure or electricity. Instead of responding like most materials, these can shrink when heated, expand when compressed, and even bounce back to their original state with the right electric charge. The work focuses on oxygen-redox (OR) materials—types that can help batteries store more energy but typically suffer from stability problems due to structural disorder.

In their normal state, the materials follow the usual rules of thermodynamics. But in what's called a “metastable” state, a kind of temporary balance, they behave in reverse. “When heated, the material shrinks instead of expanding,” said Prof. Shirley Meng, senior author of the study published in Nature. This is linked to what’s known as a disorder–order transition inside the material’s structure. The team recorded a negative thermal expansion rate of −14.4(2) × 10⁻⁶ °C⁻¹, which means the material actually contracts when warmed up. This goes against a common theory called the Grüneisen relationship, which usually explains why materials expand with heat.

And pressure? Even stranger. When they pushed the material on all sides at levels seen in Earth's tectonic plates, it expanded instead of getting smaller. “Negative compressibility is just like negative thermal expansion,” explained Prof. Minghao Zhang. “If you compress a particle of the material in every direction… it will expand.”

They also found that electricity can reset the material’s structure. By tweaking the voltage limits, they recovered almost 100% of the original structure and performance. This has big potential for battery tech, especially electric vehicles (EVs). “When we use the voltage, we drive the material back to its pristine state. We recover the battery,” said Zhang. He added: “You just do this voltage activation… your car will be a new car. Your battery will be a new battery.”

The research may lead to materials with zero thermal expansion, helpful in everything from buildings to aircraft. Zhang noted, “Take every single building, for example. You don't want the materials making up different components to change volume that often.”

As they move forward, the team wants to understand how redox chemistry can further control these effects and expand practical uses. “One of the goals is bringing these materials from research to industry,” said co-first author Bao Qiu. Their work opens up a new way of thinking about material design, where energy doesn’t just power devices, but reshapes the building blocks themselves.

Source: University of Chicago, Nature

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