Developing solid-state lithium-ion batteries

Newswise — Four South Dakota State University faculty members will help improve battery technologies through the Center for Electrochemical Energy Storage. The new governor’s research center, which is led by South Dakota Mines associate professor Alevtina Smirnova, recently received $3.9 million in state funding.

“Our priorities are to improve the safety and energy density of next-generation batteries,” said assistant professor Yue Zhou of the Department of Electrical Engineering and Computer Science. He leads the SDSU team that includes professor George Langelett of the Ness School of Management and Economics, professor Huitian Lu of construction and operations management and associate professor Matthew Biesecker of mathematics and statistics.

SDSU and South Dakota Mines researchers are using new materials to develop components for a solid-state lithium-ion battery. “We have the talent to do it,” Zhou said. Advanced battery technologies will help improve the range and safety of electric cars and the increased storage capacity will bring the power industry one step closer to integrating renewable energy into the electrical grid.

The SDSU team will receive more than $1.3 million in funding to support its work over the next five years. One postdoctoral research associate, three doctoral students and two master’s students will also work on the project.

To move those technologies toward commercialization, the research teams are also part of the Center for Solid-State Electric Power Storage, which received $2.5 million in funding from the National Science Foundation’s Industry-University Cooperative Research Center program. Both centers emphasize transitioning laboratory research to the market by collaborating with industrial partners and national research laboratories.

The partnerships with national laboratories and industry will help the researchers accomplish their goal of providing a stable battery cell that companies can mass produce.

Developing new battery materials

Lithium-ion batteries consist of two electrodes—a cathode and an anode—submerged in a liquid electrolyte and a separator. The separator is a physical barrier that keeps the cathode and anode apart. When the battery is in use, the ions move from the anode to the cathode through the electrolyte. When the battery charges, the process reverses with lithium ions migrating to the anode.

Zhou’s materials group will replace the graphite on anodes with a new material called lithium metal, while South Dakota Mines researchers will work on cathodes and solid-state electrolytes. “The capacity of conventional graphic anodes is low,” he said, noting lithium metal has the potential to increate battery capacity by 10 times.

Furthermore, Zhou explained, “Conventional electrolytes consist of lithium salt and organic solvents, which are flammable. To improve battery safety, the research group is developing novel solid-state electrolytes that will replace the separator.”

According to an article in Frontiers in Materials, solid-state electrolytes have the potential to simplify the internal structure and the packaging process of the battery and to reduce manufacturing costs.

Modeling battery performance, lifetime

Biesecker, who specializes in mathematical modeling of physical and biological processes, will use differential equations to predict how a solid-state battery performs.

“I try to build equations for how things actually work,” Biesecker said. He will begin by examining published literature, which is about 10 years old, on battery models.

"We are not starting from ground zero, as there is some previous work on mathematical modeling in the published literature, but the models have factors that are ignored or left out, so they can always be improved," Biesecker said. The model should match battery performance data from Zhou and the South Dakota Mines researchers.

"If the model is flexible enough to fit the data for a variety of existing solid-state battery cells and devices constructed, then we know it is physically sound and then we can proceed to experiment with device configurations and properties via simulation rather than in the laboratory," Biesecker said. "You can tweak things in the model to figure out what might work and, more importantly, what won't work."

Biesecker will work with Lu to predict how long a solid-state battery will last. "We will simulate the dynamics of the battery and then use algorthms to assess the battery life cycle online," said Lu, who did similar work to predict the remaining useful life of lithium-ion battery cells in a battery management system for Space Information Laboratories, which is one of the IUCRC commercial partners. Lu will also collaborate with South Dakota Mines assistant electrical engineering professor Long Zhao on this part of the project.

Finally, Lu and Langelett, who is also recruiting commercial partners, will analyze the research center’s impact on economic development. “Developing relationships with business and industry partners who are interested in these innovative technologies will help guide our research and build that commercialization connection,” Langelett said.