A team of scientists developed a key innovation for the storage of renewable energy: an organic molecule capable of storing solar energy. Then, it can be released as heat on demand, without batteries or electrical grid.
This stored energy in its chemical bonds is key because it can remain stable for years, and it has even been able to boil water.
The breakthrough, published in the journal Science, was achieved by chemists from the University of California, Santa Barbara (UCSB).
How the innovative solar energy storage system works
The molecule is called pyrimidone and its design is inspired by DNA. By absorbing ultraviolet light, it twists like a spring and gets trapped in a stable high-energy configuration for years.
Then, by adding a catalyst, the molecule relaxes and releases that stored energy as heat. Moreover, the process is completely reversible.
In addition to energy storage, after releasing the heat, this molecule can be exposed to the sun again and recharged.
“The concept is reusable and recyclable”, explained Han Nguyen, doctoral student and lead author of the study.
“It’s similar to photochromic sunglasses. Indoors they are clear lenses, you go out into the sun and they darken on their own. That reversible change is what interests us, only instead of changing color, we want to store energy,” she detailed.
What makes it different from solar panels
This innovation stands out from conventional photovoltaic systems for several reasons:
- It does not require external batteries nor does it depend on the electrical grid.
- Its energy density exceeds 1.6 megajoules per kilogram, almost double that of a standard lithium battery.
- The material can be recharged and reused almost indefinitely.
- It avoids converting light into electricity and then transforming it into heat, a process that generates losses.
“With solar panels, you need an additional battery system to store the energy,” noted Benjamin Baker, co-author of the study.
“With molecular storage of thermal solar energy, the material itself stores that energy from sunlight,” explained the specialist.
The team described the system as a “rechargeable solar battery” and has already demonstrated that the released heat is sufficient to boil water.
“Boiling water is a process that requires a lot of energy,” said Nguyen. “The fact that we can do it under ambient conditions is a great achievement.”
Spain, also at the forefront
This innovation is not an isolated phenomenon. At the Universitat Politècnica de Catalunya (UPC) in Barcelona, researchers developed the first hybrid device that combines a photovoltaic cell with a MOST system.
The molecules they use are made only with carbon, hydrogen, oxygen, fluorine, and nitrogen. They do not require rare or expensive materials, making them more accessible and sustainable.
The system serves a dual function: it stores solar energy and acts as an optical filter and cooling agent for the solar cell.
By absorbing high-energy photons, the molecules transform and store that energy for later use, while the cell operates at lower temperatures and with greater efficiency.
