As electric vehicles and electric aircraft become more common, the world’s demand for lithium-ion batteries is rising rapidly.
According to S&P Global Insights, battery demand could more than double between 2023 and 2030.
To keep up, researchers are searching for new battery designs that are not only powerful but also affordable enough to produce at massive scale.
One promising material is sulfur. It is cheap, widely available, and can theoretically store far more energy than the materials used in many batteries today.
However, sulfur has long been difficult to use in practical batteries because it does not conduct electricity well. This makes it hard for the chemical reactions inside the battery to occur efficiently.
Now researchers from the University of Chicago, the University of California San Diego, and South Korean battery company LG Energy Solution have found a way to make sulfur work in solid-state batteries.
Their study, published in Nature Communications, shows that a small change in the manufacturing process can dramatically improve battery performance.
Chen-Jui (Ben) Huang, a postdoctoral researcher working with the University of Chicago Pritzker School of Molecular Engineering and UC San Diego, explained that sulfur has always been attractive because of its extremely low cost.
But its poor electrical conductivity has prevented scientists from fully using its potential energy capacity.
Instead of adding new materials or complex coatings, the research team focused on how the battery ingredients are combined.
In solid-state batteries, the positive electrode typically contains three powdered materials: sulfur, a solid-state electrolyte that carries ions, and conductive carbon that carries electrons.
Traditionally, these powders are either mixed by hand or milled separately and then combined. Both methods have limitations. Hand mixing creates uneven contact between the particles, while multi-step milling can leave the materials poorly connected.
The researchers developed a new one-step milling method that grinds all three materials together at the same time.
This creates a more uniform mixture and improves the contact between particles. The process also forms a beneficial interface between sulfur and the electrolyte that helps the battery work more efficiently.
With this approach, the team produced a sulfur-based cathode capable of delivering about 1,500 milliampere-hours of capacity per gram of sulfur. That result is close to sulfur’s theoretical maximum of 1,675 milliampere-hours per gram, bringing scientists closer to unlocking sulfur’s full potential.
The team also discovered that the size of the electrolyte particles plays an important role. Particles at the micron scale allow the materials to pack together more tightly, improving performance.
Importantly, the researchers demonstrated the technology in a practical pouch-cell battery design rather than a small laboratory setup. Pouch cells use thin sheet electrodes and can be scaled up for real-world devices such as electric vehicles.
Solid-state batteries also offer safety advantages. Unlike conventional batteries that contain flammable liquid electrolytes, solid-state designs use dry materials that are far less likely to catch fire.
The team also found a clever way to reduce mechanical stress inside the battery. Sulfur electrodes expand and contract during charging and discharging, a process known as “breathing.” By pairing sulfur with a silicon electrode that expands and contracts in the opposite direction, the researchers were able to balance these movements and reduce internal strain.
The project highlights how collaboration between universities and industry can accelerate the development of next-generation energy technologies.
If further developed, sulfur-based solid-state batteries could offer a powerful combination of low cost, high energy density, and improved safety for the electric vehicles of the future.
Source: University of Chicago.
