One of the biggest challenges of renewable energy is what happens when the sun is not shining.
Solar panels produce electricity during the day, but storing that energy for nighttime or cloudy weather usually requires large batteries or connection to the power grid.
Scientists at the University of California, Santa Barbara have now developed a new material that could store solar energy in a completely different way — inside chemical bonds — and release it later as heat whenever needed.
The research, published in the journal Science, describes a special organic molecule that captures sunlight and locks the energy inside its structure.
The molecule, a modified compound called pyrimidone, belongs to a field known as molecular solar thermal energy storage. Instead of generating electricity, this approach stores energy directly as heat.
The idea is similar to how photochromic sunglasses darken in sunlight and return to clear indoors. The molecule changes shape when exposed to sunlight, storing energy in the process.
When triggered later by heat or a catalyst, it snaps back to its original shape and releases the stored energy as heat. Because the process is reversible, the material can be reused again and again, acting like a rechargeable solar battery.
To design the molecule, the research team took inspiration from DNA. Certain DNA components naturally change structure when exposed to ultraviolet light. By creating a synthetic version of this structure, the scientists developed a molecule that can store energy for long periods without breaking down.
Tests showed that the material has a remarkably high energy density — even higher than many lithium-ion batteries. The stored energy remained stable for years, meaning it could potentially capture summer sunlight and release heat during winter.
In a demonstration, the researchers showed that the heat released from the material was strong enough to boil water at room conditions, which is a major achievement for this type of technology. Boiling water requires a large amount of energy, so this result suggests the system could have practical uses.
Possible applications include heating homes, warming water, or providing off-grid heat for camping or remote locations. Because the material dissolves in water, it could be circulated through rooftop collectors during the day to absorb sunlight and stored in tanks for use at night.
Unlike traditional solar systems that require separate batteries, this approach allows the material itself to store energy. Scientists say it represents a new way of thinking about renewable energy storage — one that could reduce costs, simplify infrastructure, and make solar power more reliable.
Although the technology is still in development, the discovery shows how chemistry could help solve one of renewable energy’s biggest problems. If successfully scaled up, these “liquid solar batteries” could one day store sunshine for whenever we need it, bringing us closer to a future powered by clean and sustainable energy.
