Santa Barbara, CA, 2026 — Researchers at the University of California, Santa Barbara (UCSB) have developed a groundbreaking, clear, reusable liquid that directly captures solar energy and stores it as chemical energy for months or even longer. This liquid is part of a molecular solar-thermal system, eliminating the need for batteries or electricity conversion, offering an efficient and sustainable method for solar energy storage.
The Molecular Solar-Thermal System
In a study published in Science, UCSB researchers introduced a novel chemical system based on pyrimidone. When exposed to sunlight, particularly UV rays, pyrimidone undergoes a transformation from a low-energy state to a high-energy state, storing energy like a compressed spring. The energy remains stored for up to 481 days at room temperature without degradation.
To release the stored energy, the molecule only requires a small external stimulus, such as heat or a catalyst, to return to its relaxed state and release the energy as heat. The best part is that the liquid can be reused multiple times, unlike batteries that degrade after repeated cycles, offering long-term durability.
Exceptional Energy Density
The UCSB-developed liquid can store about 1.65 megajoules of energy per kilogram, nearly double the energy density of lithium-ion batteries. Unlike traditional energy storage systems that convert energy into electricity, causing inherent losses, this liquid stores energy directly in molecular form, leading to higher efficiency and minimal loss. The researchers demonstrated its practical use by boiling water with the stored energy, proving its real-world application.
Design and Stability Improvements
The project was led by Associate Professor Grace Han and doctoral researcher Han Nguyen, with computational modeling by Ken Houk at UCLA. The breakthrough design ensures the liquid remains stable at room temperature, eliminating the need for solvents that could dilute energy density. This improvement enhances both the efficiency and stability of the system.
Wide Application Potential
The potential applications of this liquid are vast. It is ideal for those needing heat but not electricity storage. The liquid can be pumped through rooftop solar panels during the day and stored in tanks for later use. When heat is needed, it can be passed through a simple reactor to release energy, perfect for heating water, space heating, or off-grid cooking. Additionally, combining it with thermoelectric materials or small turbines could generate electricity from the stored heat.
The Future of Solar Energy Storage
This breakthrough opens the door to a cleaner and more efficient way of storing solar energy. As the technology advances, this liquid could play a key role in residential, industrial, and off-grid energy solutions, providing a new way to store and use solar energy for extended periods, pushing the future of renewable energy.
