Researchers at Chalmers University of Technology in Sweden have developed a molecule-based system that stores solar energy in liquid form — and can release it as electricity up to 18 years later. The breakthrough, published in Cell Reports Physical Science, introduces a new class of technology called Molecular Solar Thermal Energy Storage Systems, and it recently passed a striking proof-of-concept test: stored Swedish sunlight was shipped to China and successfully converted into electricity three months later.
At a glance
- Solar energy storage: A specially engineered molecule changes shape when it absorbs sunlight, forming an energy-rich isomer that holds its charge in liquid — releasing heat and generating electricity only when a catalyst triggers the reverse reaction.
- Molecular solar thermal: The storage medium has a theoretical shelf life of up to 18 years, meaning energy captured today could power a device nearly two decades from now with no battery degradation.
- Microchip generator: A Chinese research team converted the stored energy using an ultra-thin chip — just 800 nanometers thick on a three-inch silicon wafer — small enough to be embedded in headphones, smartwatches, or phones.
How the molecule works
The science hinges on a principle most people encounter in everyday chemistry without realizing it: when matter changes form, energy moves with it.
Research leader Kasper Moth-Poulsen, a professor at the Department of Chemistry and Chemical Engineering at Chalmers University, designed a molecule built from carbon, nitrogen, and hydrogen. When sunlight hits it, the molecule rearranges into an isomer — a different structural configuration that is stable in liquid and holds its energy like a coiled spring. Nothing is released until a catalyst tells it to unwind.
“This is a radically new way of generating electricity from solar energy,” Moth-Poulsen told Euronews. “It means that we can use solar energy to produce electricity regardless of weather, time of day, season, or geographical location.”
The China test
The cross-continental experiment gave the technology its most compelling demonstration yet. Moth-Poulsen’s team in Sweden charged the liquid with sunlight, then shipped it to collaborator Zhihang Wang at a Chinese partner institution. Wang’s team fed the liquid through their microchip generator, and it produced electricity.
“So far, we have only generated small amounts of electricity, but the new results show that the concept really works,” Wang said. “It looks very promising.”
The microchip itself is a feat of miniaturization. Thermal electricity generation — converting heat into electrical current — is a well-established industrial process. Wang’s team compressed it into an 800-nanometer-thin film on a three-inch silicon wafer. The vision is a small device that accepts charged liquid from a dedicated station, then powers electronics on demand, as described in the published study.
Why this matters beyond big solar
Most solar storage conversation focuses on grid-scale batteries — large installations that buffer the mismatch between when panels generate power and when people use it. Projects like pumped hydro and grid-scale lithium dominate that space. This research points somewhere different: small, personal, portable energy storage that needs no mining-intensive battery chemistry.
The implications reach places conventional solar panels never could. A remote medical device. A sensor in a polar research station. Consumer electronics charged months in advance. Because the liquid holds its energy passively — no cooling, no degradation, no discharge curve — it could supply power in contexts where today’s batteries simply fail.
The Chalmers molecular solar thermal research group has been refining this chemistry for over a decade, and this result is the clearest sign yet that the approach can move from laboratory curiosity to functional device.
What still needs to happen
Both teams are careful about what “promising” means at this stage. Electricity output so far is small, and scaling the charging and conversion system into a consumer product will require engineering advances that don’t yet exist. The efficiency of converting stored heat to electricity through the chip also needs significant improvement before the technology competes with conventional batteries on practical terms.
But the core concept — storing solar energy as molecular potential rather than electrochemical charge — is now validated across a three-month, intercontinental round trip. That is the kind of result that moves a technology from theoretical to fundable.
Read more
For more on this story, see: Good News Network
For more from Good News for Humankind, see:
- Renewables now make up at least 49% of global power capacity
- U.K. cancer death rates down to their lowest level on record
- The Good News for Humankind archive on clean energy
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