A liquid that behaves like a rechargeable solar battery harvests energy from sunlight, stores it for months, and then delivers the energy when needed.
The material transforms from a yellow liquid to a black gel when it charges up, and then releases its energy and reverts back to its liquid form when exposed to open air. It can then be recharged over and over again.
By combining energy harvesting, storage, and use into one platform, the material could enable a simple new clean energy system. The researchers estimate that just one gram of the material could hold enough power to charge a smartwatch or other wearable device, according to a press release.
“For energy storage, our material performs the same function as a battery,” said Northwestern University chemistry professor Samuel Stupp. “However, it runs entirely in water, requires no metal or plastics and can be recharged repeatedly. This kind of clean, flexible platform could open new doors for renewable energy.”
Solar panels are the most common way to harvest the sun’s energy, but they don’t store that energy. Solar fuels, which are made by using sunlight to drive chemical reactions between common substances such as water and carbon dioxide, are another way to store solar energy.
In an effort to use sunlight more efficiently and store it longer, researchers have more recently developed ways to store solar energy in the chemical bonds of molecules. The new work is an advance in such solar liquid battery systems. Besides sunlight, the new liquid can also harvest energy from electricity, X-rays and other energy sources.
Stupp and his colleagues were inspired by the cytoskeleton of biological cells. This internal scaffolding constantly disassembles and then rebuilds itself so that cells can move and divide.
The new material which the team reported in the journal Chem behaves in a similar way. “Living systems are remarkably dynamic,” Stupp said. “We wanted to create a synthetic material that behaves in a similar way while performing useful functions.”
To make the material, the researchers used so-called supramolecular materials: molecules that self-organize into larger structures. The designer molecule combines two main parts: a unit that responds to light, and another one that stores electrons.
The light-responsive portion absorbs energy and transfers electrons to the second unit. This causes neighboring molecules to strongly attract and form pairs, which then come together to form tiny ribbon-like structures. The ribbons then entangle, which makes the material morphs into the black gel. But electrons move freely through the structure, so the gel stores electrons in its network.
Source: Tyler J. Jaynes et al. Dynamic self-assembly mediated by stored and released electrons in pimer supramolecular polymers of chromophore amphiphiles. Chem, 2026.
Image: ©Anthropocene Magazine
