We rely on rechargeable batteries every day, from electric cars to wireless headphones. Most of them use liquid electrolytes that help store and release energy quickly. However, these liquids can catch fire if the battery fails or overheats, making them a safety risk.

Researchers at the University of Missouri are working on a solution. Associate professor Matthias Young and his team are developing batteries that replace liquid electrolytes with solid materials, reports the specialist website Knowridge.

These batteries have the potential to be safer and more efficient, but there is a major challenge holding them back.

When a solid electrolyte touches the cathode of a battery (the part where electricity is stored and released), a very thin layer forms between them - about 100 nanometres thick.

This layer prevents lithium ions from moving freely, which increases resistance and degrades battery performance.

Scientists have been struggling with this problem for more than a decade, but Young's team made a major breakthrough in understanding the root cause.

Using four-dimensional scanning transmission electron microscopy (4D STEM), the researchers were able to look inside the battery without disassembling it.

This cutting-edge technology allowed them to see at the atomic level how this unwanted layer forms and how it affects the battery's function.

Young's lab specializes in creating thin protective coatings using a technique called oxidative molecular layer deposition (oMLD). Their next step is to see if these coatings can prevent an unwanted reaction between the solid electrolyte and the cathode.

"The coatings have to be the right thickness," explains Yang. "They need to stop the reaction but still allow the lithium ions to move freely so that the battery can continue to operate efficiently."

By carefully designing these nanowire coatings, Young's team hopes to make solid-state batteries work without loss of efficiency. If successful, this technology could lead to safer, longer-lasting and more powerful batteries for everything from smartphones to electric vehicles.

The study, published in Advanced Energy Materials, was co-authored with researchers Nikhila C. Paranamana, Andreas Werbrouck, Amit K. Datta and Xiaoqing He from the University of Missouri. | BGNES