SwRI and SMU to deposit nanoscale films on solid-state battery anodes

Southwest Research Institute (SwRI) and Southern Methodist University (SMU) are collaborating on a design architecture for solid-state batteries. The work focuses on the interface between the lithium metal anode and the solid electrolyte.

Solid-state batteries replace the liquid electrolyte used in current EV batteries with a solid material, and use a lithium metal anode as the source of lithium ions. That combination, according to SwRI, enables faster charging and higher energy density, and replacing flammable liquids with solid materials makes operation inherently safer.

In SwRI’s design, as solid lithium metal anode sits in direct contact with the solid electrolyte. Lithium is highly reactive and can damage or chemically interact with the materials it touches, compromising the battery’s performance and stability.

“Solid-state batteries are a next-generation technology with huge potential for energy storage, particularly for electric vehicles, but they haven’t been widely commercialized because of manufacturing and materials challenges,” said John Hemmerling, a Senior Research Engineer in SwRI’s Materials Engineering Department. “One of the biggest technical hurdles is the unstable interface between the lithium metal anode and the solid electrolyte.”

“The lithium can also deposit in uneven growths, known as dendrites, that damage the contact area and hinder the transfer of ions,” Hemmerling said. “This accelerates battery degradation, making the battery less efficient over time.”

To mitigate these effects, the researchers are working on a process called interfacial engineering. They plan to deposit films tens to hundreds of nanometers thick onto the anode in order to reduce degradation and resistance at the anode-electrolyte interface. The films include metals, metal oxides and metal alloys, tuned to stabilize the interface.

The project combines SwRI’s thin-film deposition work and SMU’s solid-state battery development work, and aims to establish quantitative structure-property-performance relationships linking interfacial chemistry, lithium nucleation behavior and long-term electrochemical performance.

“Although our current work is focused on a small, proof-of-concept scale, the thin-film deposition techniques we’re using are scalable, so if the concepts prove successful, they can be adapted relatively easily to larger-scale manufacturing,” Hemmerling said.

Source: Southwest Research Institute