Low-battery anxiety may soon be a little less stressful thanks to a recent discovery by researchers at the University of Houston.
For decades, scientists have struggled to understand what, exactly, is happening inside a solid-state battery in real time, which has made extending its life difficult. Now, a UH research team, in collaboration with researchers from Brown University, worked around that problem using operando scanning electron microscopy, a powerful high-resolution imaging technique. The technique helped them understand why solid-state batteries break down and what could be done to slow the process.
"This research solves a long-standing mystery about why solid-state batteries sometimes fail," said Yan Yao, the Hugh Roy and Lillie Cranz Cullen Distinguished Professor of Electrical and Computer Engineering at UH and the corresponding author of this study published in the journal Nature Communications. "This discovery allows solid-state batteries to operate under lower pressure, which can reduce the need for bulky external casing and improve overall safety."
Prior to this revelation, scientists knew adding small amounts of other metals, such as magnesium, to lithium negative electrodes helped improve battery performance, but they didn't understand why, said Yao, who is also the principal investigator at the Texas Center for Superconductivity at UH.
What Yao's team learned is that over time, tiny empty spaces, or voids, form within the battery and merge into a large gap, ultimately causing the battery to fail.
After a series of experiments, the team found that adding small amounts of alloying elements like magnesium can close these voids and help the battery continue to function.
"We captured real-time, high-resolution videos of what actually happens inside a battery while it's working under a scanning electron microscope," said Lihong Zhao, the first author of this work, a former postdoctoral researcher in Yao's lab and now an assistant professor of electrical and computer engineering at UH. "With just a small tweak to the battery's chemistry, we can dramatically improve its performance, especially under practical conditions like low pressure."
This discovery is a big step forward for electric vehicles. Currently, solid-state batteries are not ideal for daily use in vehicles. While they are more fire resistant and have the potential to reach high energy density, they also require high external stack pressure to stay intact while operating.
"But by carefully adjusting the battery's chemistry, we can significantly lower the pressure needed to keep it stable," Zhao said. "This breakthrough brings solid-state batteries much closer to being ready for real-world EV applications."
"This breakthrough brings solid-state batteries much closer to being ready for real-world EV applications."
— Lihong Zhao, assistant professor of electrical and computer engineering, University of Houston
This research could also prevent batteries in cell phones and other electronics from overheating or catching fire. Additionally, these batteries could last much longer on a single charge.
"It's about making future energy storage more reliable for everyone," he said.
Yue Qi from Brown University, an expert in computational materials, provided theoretical analysis and was the co-corresponding author of this research.
Other contributors are Min Feng from Brown; Chaoshan Wu, Liqun Guo, Zhaoyang Chen, Samprash Risal, Zheng Fan from UH; and Qing Ai, Jun Lou from Rice University.
This work was supported by the US Department of Energy's Battery 500 Consortium under the Vehicle Technologies Program.
"The team plans to build on this alloy concept by exploring other metals that could improve battery performance," Zhao said.
