The Unseen Breath of Batteries: Understanding Their Deterioration
In a breakthrough study, researchers have uncovered a critical factor contributing to the gradual decline of batteries, which power devices ranging from smartphones to electric vehicles. This discovery could pave the way for the development of batteries that are faster, more reliable, and have a longer lifespan.
A collaborative research team from The University of Texas at Austin, Northeastern University, Stanford University, and Argonne National Laboratory has revealed that the charging and discharging cycles cause batteries to expand and contract, akin to a human’s breathing process. This repeated action leads to slight warping of battery components, exerting stress and weakening the battery over time—a phenomenon termed “chemomechanical degradation.”
This new insight addresses a longstanding puzzle that has challenged scientists and engineers globally.
“With every ‘breath’ of the battery, there’s some degree of irreversibility,” states Yijin Liu, an associate professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering and Texas Materials Institute and leader of the study, which is published in Science. “This effect accumulates over time, eventually causing failure of the cell.”
Significantly, the researchers identified “strain cascades”—a chain reaction where stress originates in one section of the electrode and progressively affects neighboring areas. The erratic behavior of the countless particles within batteries contributes to this strain.
Juner Zhu, assistant professor of mechanical and industrial engineering at Northeastern and a coauthor of the study, explains, “We were able to see that every particle behaves differently under electrochemical stress. Some particles move rapidly, like shooting stars in the sky, while others remain relatively stable. This uneven behavior creates localized stress that can lead to cracks and other damage.”
By gaining a deeper understanding of how stress develops and propagates, engineers can design electrodes that better withstand strain and degradation. The study suggests that applying controlled pressure to battery cells could be a method to alleviate strain and improve performance.
“Our ultimate goal is the creation of advanced technologies that can substantially increase the utility and durability of batteries,” remarks Jason Croy, coauthor and group leader for the Materials Research Group at Argonne National Laboratory. “Understanding how the design of electrodes influences their response to stress is a critical step in pushing the boundaries of what batteries can do.”
To arrive at these findings, the research team utilized cutting-edge imaging techniques to monitor battery electrodes in real time during the charging and discharging processes. Advanced tools such as operando transmission X-ray microscopy (TXM) and 3D X-ray laminography were employed to capture intricate images of particle movement and interaction within the electrodes.
Interestingly, the researchers first noticed this dynamic in a device used for a different study, commercial earbuds. They intend to continue this line of research, with the next phase focusing on developing theoretical models to better comprehend the complex interactions between chemical and mechanical processes in battery electrodes.
This research received funding from the US Department of Energy’s Vehicle Technologies Office. Contributors to the study also included researchers from UT, Northeastern University, Sigray Inc., Stanford and SLAC National Accelerator Laboratory, and Argonne National Laboratory.
Source: UT Austin
Original Story at www.futurity.org