Innovative Metal Design Enhances Solid-State Battery Performance at Lower Pressures

A New Metal Design for Solid-State Batteries
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June 5, 2025 — Sun Geun Yoon works in a glove box in McDowell’s laboratory at Georgia Tech.

Lithium-ion batteries are the driving force behind many devices, from electric cars to laptops and even leaf blowers. Despite their widespread use, these batteries have limitations in energy capacity and pose safety concerns due to the risk of overheating. For decades, researchers have been on the lookout for a more reliable battery solution.

Solid-state batteries present a safer alternative, as they are less flammable and can store more energy. However, they often require intense pressure to function properly, which has hindered their application. New research from Georgia Tech offers a promising breakthrough in this area.

The research team, led by Matthew McDowell, a professor and the Carter N. Paden Jr. Distinguished Chair in the George W. Woodruff School of Mechanical Engineering and the School of Materials Science and Engineering, has developed a new metal composition for solid-state batteries that allows them to operate at lower pressures. While lithium metal is commonly used in these batteries, McDowell’s group found that combining lithium with softer sodium metal results in enhanced performance and unique characteristics. Their findings were published in the paper titled “Interface Morphogenesis with a Deformable Secondary Phase in Solid-State Lithium Batteries” in *Science* on June 5.

### Stackable Solution

Lithium-ion batteries have long been the industry standard due to their compact size, reliability, and durability. However, they rely on a liquid electrolyte, which facilitates the movement of lithium ions but is also flammable. In contrast, solid-state batteries use a solid electrolyte that is less hazardous. The challenge lies in the fact that, during usage, the lithium metal can change shape, potentially losing contact with the solid electrolyte and degrading performance. To mitigate this issue, high pressure is typically applied to maintain contact.

“A solid-state battery usually requires metal plates to exert this high pressure, and those plates can be larger than the battery itself,” McDowell explained. “This makes the battery too heavy and bulky to be practical.”

In search of a solution, the researchers, led by Georgia Tech research scientist Sun Geun Yoon, found that while solid-state batteries still need some pressure, using a softer metal could reduce the required pressure. They opted to combine the frequently used lithium metal with sodium, a less conventional choice.

“Adding sodium metal is the breakthrough,” McDowell emphasized. “It may seem counterintuitive since sodium is not active in the battery system, but its softness significantly enhances lithium’s performance.”

How soft can sodium be? In a controlled environment, one could press a gloved finger into sodium metal and leave an imprint.

### From Biology to Battery

To understand the improved performance of their battery, the researchers drew inspiration from a biological concept called morphogenesis, which describes how tissues or structures develop in response to local stimuli. Although morphogenesis is rarely observed in materials science, McDowell’s team discovered that the combination of lithium and sodium exhibits behavior akin to this concept.

As part of a project funded by the Defense Advanced Research Projects Agency (DARPA) in collaboration with several universities, McDowell’s group has been applying morphogenesis principles to battery materials. Their findings represent one of the first successful applications of this concept, demonstrating that sodium can deform effectively at the lower pressures necessary for solid-state batteries to operate.

### Battery Boon

The potential for a smaller, efficient solid-state battery is immense. Imagine a smartphone battery that lasts significantly longer or an electric vehicle capable of driving 500 miles on a single charge. In light of these possibilities, McDowell and his team have filed for a patent for their innovative battery system.

While solid-state batteries still have some challenges to overcome before they can be commercialized, advancements like these suggest that they may soon compete with lithium-ion batteries. McDowell’s lab is actively exploring additional materials to further enhance battery performance.