Scientists "bottle the sun" with a liquid battery that stores solar energy

May 15, 2026 Last reply: 2 months ago 6 Replies
J

From:

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Scientists “bottle the sun” with a liquid battery that stores solar energy Researchers created a “rechargeable sun battery” that stores sunlight in molecules and later releases enough heat to boil water. Date: May 14, 2026 Source: University of California - Santa Barbara Summary: Scientists at UC Santa Barbara have created a remarkable new material that works like a “rechargeable solar battery,” storing sunlight inside tiny molecules and releasing it later as heat — even long after the sun goes down. Inspired by reversible changes found in DNA and photochromic sunglasses, the system captures solar energy without relying on bulky batteries or the electrical grid. The molecule can hold energy for years and packs more energy per kilogram than lithium-ion batteries.



quote: New Material Can Boil Water Using Stored Sunlight


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M

The stored energy density is quite impressive if that is true. Toxicity and difficulty of manufacture isn't mentioned but might be a problem. I wonder how photochemically stable it is when exposed to sunlight!

Very few organic dyes are photostable in sunlight - absorbing blue and UV energetic photons takes its toll on the molecules that do it!

OTOH polymer LEDs were unstable grey goo with faint light output that lasted for about 5s when I was at university. Now they are in many consumer TVs (so about 4 decades from bench to consumer product).

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J

[...]

Interesting, but there's not a lot of power at 300nm or shorter in sunlight at ground level. This may hold promise for heating buildings, although I don't fancy storing a tons of pyrimidone in the basement.

Jeroen Belleman

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J

I don't have access to the original paper, but wondered how they get back to the original state after the acid catalysis to produce heat:

"To demonstrate practical heat release and transfer, Dewar pyrimidone was dissolved in water, and an acid catalyst was used to promote the back isomerization. Addition of hydrochloric acid (HCl) to Dewar pyrimidone (107 mg in 0.46 ml of water) increased the solution temperature to 100°C and induced boiling within 1 s."

All it states in the supporting paper at

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, in section 11.1 is:

"1.11. Cycling Test in Water A cuvette solution of P-3 in degassed HPLC-grade water (2.8 mL, 2.5 ×

10−5 M) was initially irradiated at 310 nm for 2 hours and 20 minutes to achieve full conversion to D-3. HCl (10 μL, 2 M) was then added to regenerate pyrimidone 3 in its salt form (P-3+). For the second cycle, the acidic solution was neutralized with excess saturated NaHCO3 (30 μL, 10% w/w), followed by irradiation at 310 nm for 2 hours and 20 minutes, then acidified again with HCl (10 μL, 2M) to regenerate P-3+. The UV-Vis absorption spectrum before and after each step were recorded and presented in Fig. S48."

Is it a "closed system" or not? Seems like they add HCl to start the reaction, and neutralise it with NaHCO3.

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J

I like the jug full of sparks.

This is even better:

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When it's sunny, it gets energy from light. When it's raining, it gets energy from the impact of the raindrops.

That's a win-win. It could probably collect moonlight too.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

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J

No idea, but maybe our chemical giant Bill SLoman can explain?

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M

I suspect *that* may be it's Achilles heal. I wonder how many days it will take to recharge a few kilos of the stuff at ground level in sunlight. Flipping it on/off by small pH changes seems trivial by comparison.

This may hold promise for heating

Me neither. Impressive energy storage density though.

Various phase change inorganic salts have been proposed in the past. Sulphates and Thiosulphates being amongst the most well known.

Various other phase change based thermal storage systems are known:

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Some fairly exotic eutectic mixtures used in solar concentrators.

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