Researchers at UC Santa Barbara describe a modified organic molecule called pyrimidone that captures sunlight, stores the energy in chemical bonds, and releases it later as heat. Associate Professor Grace Han led the work and doctoral student Han Nguyen is the paper’s lead author. They focused on a compact design and removed unnecessary parts so the molecule can switch shape repeatedly.
The team built on Molecular Solar Thermal (MOST) concepts and used inspiration from a DNA component that changes under UV light. Computational modeling with Ken Houk at UCLA helped explain why the molecule can hold energy and remain stable for years without losing the stored energy. The molecule behaves like a twisted spring: sunlight puts it into a strained, high-energy shape and a small amount of heat or a catalyst returns it to a relaxed state, releasing heat.
The new molecule has an energy density of more than 1.6 megajoules per kilogram, compared with around 0.9 MJ/kg for a standard lithium-ion battery. In lab tests the released heat boiled water under ambient conditions. Because the material dissolves in water, it could be pumped through roof-mounted collectors and stored in tanks for night use. Possible applications include off-grid heating for camping and residential water heating. Benjamin Baker, a coauthor, notes the material itself stores sunlight without an extra battery system.
Difficult words
- pyrimidone — a modified organic molecule that stores light energy
- molecule — a group of atoms bonded together, smallest unit
- molecular solar thermal — a method to store solar energy in chemicals
- energy density — amount of energy stored per unit mass
- catalyst — a substance that speeds up a chemical reaction
- dissolve — to mix into a liquid and disappeardissolves
- strained — in a tense or stressed physical shape
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- What advantages might this sunlight-storing material offer for people who camp or live off-grid?
- What challenges do you think could come from pumping a dissolved material through roof-mounted collectors and storing it in tanks?
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