Flower Power:
Lavender Oil Fuels Batteries for the Future
A groundbreaking sodium-sulfur battery with improved energy performance and longer lifespan? The secret ingredient grows in our gardens: lavender. By combining lavender oil with sulfur, Dr. Paolo Giusto's team has created a unique material that solves a persistent failure problem – polysulfide shuttling. This research marks an important step toward developing more powerful and sustainable batteries for the next-generation large-scale energy storage systems.
Little did Alessandro Volta imagine to what extent his invention, the battery, would transform our lives. It has been a long journey from his initial stack of metal discs to the pocket-sized powerhouses in our portable devices and the large grids supplying factories. Today, scientists are exploring alternatives to the traditional lithium-based batteries which cause significant pollution at every stage – from the extraction of critical components to the energy-intensive manufacturing and disposal of toxic waste. Dr. Paolo Giusto’s team at the Max Planck Institute of Colloids and Interfaces is working on sodium-sulfur batteries, a promising option made from readily available elements and using fewer hazardous chemicals.
But these emerging greener batteries do not come without their challenges. The most substantial is polysulfide shuttling, or the formation of compounds that interfere with the mechanism at the heart of how batteries work. Polysulfides are unwanted byproducts that clog the battery and, when diffusing, can lead it to complete failure. Giusto and his research team added an unexpected yet game-changing ingredient to the synthesis pot: lavender oil.
Dr. Evgeny Senokos combined linalool from lavender oil with sulfur and heated the mixture to create a new material that acts like a confinement cage for sulfur and polysulfides. Its nanopores (about a hundred thousand times smaller than a human hair) trap the polysulfides but allow the passage of smaller sodium ions, ensuring a continuous transfer of electrons. "Lavender oil proved to be the ideal addition thanks to its thermal cross-linking and condensation. In easier words, as the temperature inside the battery rises, its carbon molecules bind more tightly, and as the water evaporates, the resulting nanocage becomes stronger and denser. This continuous layer of carbon traps the sulfur, preventing its escape. And we get a battery that lasts longer and stores more energy," explains Senokos. Determined to make an impact on green energy, he will soon lead his own group in the pursuit of viable lithium alternatives.
After undergoing 1,500 lab tests over three months, the lavender-tweaked battery still retained more than 80% of its original capacity.
"If we look at nature with a creative eye, it offers solutions to many challenges of the energy transition. I am confident that our results will soon find their way out of the lab into real-world applications," asserts Giusto. Once properly scaled up, the innovative batteries could power industrial grids, store energy from renewable sources, and back up essential infrastructure. “It's intriguing to shape future batteries with something that many of us grow in our gardens," Giusto adds, as the pungent scent of sulfur in his lab gives way to lavender, reminiscent of the fields in his native Riviera dei Fiori, Italy that have inspired this work.
The future of green batteries may not be rosy yet, but it is certainly lavender-tinted.
Find out more about the “2D-Covalent Thin Films for Energy Storage” research group.