Using solar energy to generate electricity after sunset: A team of researchers has “hacked” wood to make it possible

If I told you that a piece of wood can generate electricity in the dark, you'd think it was science fiction, wouldn't you? But in fact, a team of Chinese researchers has taken balsa wood, known for its extreme lightness, and transformed it into a kind of natural battery capable of storing sunlight during the day and releasing it as electrical energy when it is already night outside. Most of us think that solar energy is a wonderful idea, but that it has an insurmountable flaw: when the sun goes down, the panels become useless, precisely at the time when energy demand rises. But this belief could be challenged: the new frontier is not just about absorbing light, but about being able to store it in natural materials and release it when needed—even after sunset. The team from Kunming University, led by scientists who published their work in Advanced Energy Materials, took balsa wood and subjected it to a veritable chemical “hack.” First, they removed the lignin, making the wood even more porous. Then they coated the interior with nanosheets of black phosphorene, a material that can absorb a very wide range of light, from ultraviolet to infrared, but which normally degrades easily when exposed to air. To protect it, they coated each individual nanosheet with a layer of tannic acid and iron ions. But they didn’t stop there: They added silver nanoparticles, which boost light absorption, and hydrocarbon chains, which not only make the wood waterproof but also act as true solar energy stores. The final touch came with stearic acid: when the sun heats this compound, it stores heat and releases it gradually, even after the sunlight has gone. The key moment comes in the laboratory: when put to the test, the “enhanced” balsa wood achieved a conversion efficiency of 91.2% and was able to generate up to 0.65 volts of electricity—in the dark. The researchers state it clearly: this could become an environmentally friendly and scalable platform for capturing and delivering solar thermal energy. We may not yet see our homes lit solely by pieces of magical wood, but the idea of “hacking” natural materials to overcome the limitations of traditional batteries is a game-changer. And here comes a question that no one is asking: If today we use lithium-ion batteries, which pose enormous disposal and pollution problems, what will happen if tomorrow the best solution is a plant-based, biodegradable, and potentially renewable material? Perhaps the future of energy is not only high-tech, but also “high-nature.” Solar energy doesn’t run out when the sun goes down—you just need to change the material that captures it. If this story about wood producing energy in the dark has sparked your interest, you can mark it on Lara Notes with I'm In: it's not just interest; it's your decision to support a new idea. And when you tell someone that a group of scientists have “hacked” wood to turn it into a kind of natural battery, on Lara Notes you can tag the person you talked to about it using Shared Offline—because certain conversations are worth remembering. This Note comes from Wired Italia: You have just saved almost 4 minutes compared to the original article.