How Sunburn Inspired a New Way to Store Energy

Why It Matters

MOST technology could provide cheap, long‑duration heat storage, reducing dependence on fossil fuels for residential and industrial heating and enhancing energy resilience.

Key Takeaways

• UCSB team achieved 1.65 MJ kg⁻¹ energy density, surpassing Li‑ion batteries
• Molecules mimic DNA repair, storing heat when exposed to UV light
• Current trigger uses hydrochloric acid, posing corrosion and safety challenges
• Researchers aim for solid‑state, visible‑light‑responsive designs for practical deployment

Pulse Analysis

Molecular solar‑thermal (MOST) storage has long been touted as a low‑cost, emission‑free way to capture solar heat for later use. Unlike batteries, which store electrical energy, MOST materials absorb photons and convert them into chemical strain, holding the energy for months or even years. The concept promises a density comparable to fossil fuels while avoiding the safety and resource constraints of lithium‑ion cells. As the world seeks solutions for seasonal heating—an area where renewables currently fall short—researchers have pursued photo‑responsive molecules that can be cycled repeatedly with minimal loss.

In February, Grace Han’s team at the University of California, Santa Barbara reported a MOST system that reached 1.65 MJ kg⁻¹, roughly 1.6 times the energy density of the best lithium‑ion batteries. The breakthrough relied on DNA‑inspired molecules that twist under 300 nm ultraviolet light, storing enough heat to boil a tiny volume of water in seconds. While the laboratory demonstration used hydrochloric acid to release the stored energy—a corrosive and energy‑intensive step—the result proves that molecular strain can deliver practical heat on demand. The work also highlights the power of computational screening in identifying high‑performing candidates.

Industry observers see solid‑state MOST as the next milestone because it could eliminate the need for liquid handling and toxic triggers. Researchers are exploring polymer matrices and transparent coatings that respond to visible light, which would make integration into windows or building façades feasible. If scalability and durability are achieved, MOST could provide long‑term, on‑site heat for residential and commercial buildings, reducing reliance on natural‑gas boilers and insulating the grid from geopolitical supply shocks such as the Strait of Hormuz blockage. Nevertheless, challenges in light penetration, material stability, and cost must be resolved before the technology moves beyond pilot plants.