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Soft metal solid-state battery mimics biology, could drive EVs 500 miles per charge
Researchers at Georgia Tech have developed a new metal combination that could transform the future of solid-state batteries.
By blending lithium with a soft, surprising element, sodium, the team has found a way to reduce the pressure needed for these batteries to operate significantly.
This innovation could lead to lighter, longer-lasting power sources for everything from smartphones to electric vehicles.
The findings were published by the lab of Matthew McDowell, a professor in Georgia Tech's School of Mechanical Engineering and the School of Materials Science and Engineering.
His group has also filed for a patent on the breakthrough.
Solid-state batteries promise greater energy density and better safety than lithium-ion ones. They use a solid electrolyte instead of a flammable liquid, making them more stable.
However, they often require high pressure to work. The metal plates needed to apply that pressure are often heavier and bulkier than the battery itself.
'A solid-state battery usually requires metal plates to apply this high pressure, and those plates can be bigger than the battery itself,' McDowell said. 'This makes the battery too heavy and bulky to be effective.'
That challenge has kept solid-state batteries from reaching widespread use, despite years of research and hype.
The team, led by Georgia Tech research scientist Sun Geun Yoon, found that adding sodium to lithium changes the game.
Sodium is not active in the battery's electrochemical process, but its softness plays a key role.
'Adding sodium metal is the breakthrough,' McDowell said.
'It seems counterintuitive because sodium is not active in the battery system, but it's very soft, which helps improve the performance of the lithium.'
Sodium's softness is no exaggeration. In a controlled setting, someone could press a gloved finger into the metal and leave a mark.
When paired with lithium, it deforms easily under lower pressure, keeping better contact with the solid electrolyte. This improves overall battery performance.
To understand why sodium-lithium batteries perform better, the team turned to biology. Specifically, they used the concept of morphogenesis — the way biological structures evolve based on local conditions.
Morphogenesis is rare in materials science. But in this case, the interaction between sodium and lithium followed this pattern.
The researchers saw that sodium behaved like a deformable phase, adjusting to structural changes during battery use.
McDowell's team developed this concept under a project funded by the Defense Advanced Research Projects Agency (DARPA), alongside other universities.
The implications of this research are broad. It could lead to phone batteries that last far longer or electric vehicles capable of going 500 miles on a single charge.
The ability to reduce the pressure requirement without sacrificing energy capacity opens new possibilities for scaling solid-state batteries.
While challenges remain before commercialization, McDowell's group continues to test new materials.
Their goal is to make solid-state batteries more competitive with the lithium-ion standard. If successful, this shift could mark a major leap in battery technology.
The study is published in the journal Science.
