A method developed by Argonne scientists to coat sulfide-based solid electrolytes is reported to extend battery life and lower manufacturing costs.
LEMONT, Ill.—Protective barriers are important to humans in myriad situations of everyday life. Sunscreens shield us from the sun, umbrellas keep us dry in the rain, and oven mitts protect our hands from hot pans.
Similarly, batteries need protection to prevent their internal components from breaking down due to environmental exposure.
Inside a battery, the electrolyte is the chemical medium that allows electrical charge to flow between components. Solid-state batteries (SSBs) use solid electrolytes instead of the liquid electrolytes found in regular lithium-ion batteries. By using solid electrolytes, solid-state batteries could revolutionize energy storage by offering better energy density, safety, and lifespan, according to a release from the U.S. Department of Energy’s Argonne National Laboratory.
However, a big challenge for solid-state batteries is that solid electrolytes can break down when exposed to humidity and oxygen.
“This is particularly severe for high-performance, sulfide-based solid electrolytes, such as lithium phosphorus sulfur chloride (LPSCl),” the release stated. “Making SSBs with these materials requires maintaining a dry room below -40°C, which makes production costly.”
To improve chemical stability and make manufacturing more affordable, researchers at Argonne National Laboratory have developed a method to coat sulfide-based solid electrolytes. They use atomic layer deposition (ALD) to apply a protective layer. This coating improves stability by acting as a shield and modifying the surface’s electronic structure, resulting in materials that are more resistant to moisture and oxygen, the release said.
“Our research shows that even a very thin coating—just a few nanometers thick—can act as a strong barrier, keeping the electrolyte intact and boosting its performance,” said Argonne materials scientist Justin Connell, in the release. “This breakthrough can extend battery life and lower manufacturing costs by allowing production in less controlled environments.”
The ALD process deposits a layer of aluminum oxide onto the electrolyte particles. In tests with high humidity and oxygen, the coated electrolytes were reported to have performed much better than uncoated ones, remaining stable with little degradation.
The ability to work with these materials in less controlled environments is a key advantage. Materials scientist Zachary Hood noted that handling these materials under harsher conditions would simplify manufacturing.
“It would allow manufacturers to use existing infrastructure, similar to what is used for lithium-ion batteries,” he said. “This would result in significant savings in the upfront cost of factories, while also improving reliability.”
The Argonne team is working to scale up this method and is collaborating with a commercial partner to produce larger quantities of the coated electrolyte for demonstration in larger format batteries. Future research is expected to focus on exploring other coating chemistries.