Scientists at The University of Texas at Austin, Northeastern University, Stanford University and Argonne National Laboratory have linked a common mechanical process to the gradual loss of performance in rechargeable batteries. They show that every charge and discharge cycle makes cells expand and contract — a "breathing" motion that causes tiny irreversible shape changes and internal stress. This chemomechanical degradation accumulates and eventually shortens battery life, a result reported in Science.
A central discovery is the phenomenon the team calls "strain cascades." Stress may concentrate in one region of an electrode and then propagate to neighbouring areas because the hundreds of thousands of particles inside an electrode do not move uniformly. Some particles change quickly while others remain relatively stable. This uneven behaviour produces localised stress that can drive cracks and other damage over time. Yijin Liu noted that each battery "breath" includes some irreversibility that builds up until the cell fails, and coauthor Juner Zhu described how variable particle motion produces concentrated stress.
The researchers captured these processes using operando transmission X-ray microscopy (TXM) and 3D X-ray laminography, observing particle motion in real time; the behaviour was first seen in commercial earbuds used in a separate project. Understanding how strain forms and spreads points to practical approaches: engineers could design electrodes to better resist stress or apply controlled pressure to reduce damage. The team plans to develop theoretical models to explain the coupled chemical and mechanical interactions. The work received funding from the US Department of Energy’s Vehicle Technologies Office and included contributions from UT, Northeastern, Sigray Inc., Stanford, SLAC National Accelerator Laboratory, and Argonne National Laboratory.
Difficult words
- chemomechanical — combined chemical and mechanical deterioration process
- strain — deformation or internal stress in a material
- cascade — a series of events that spread sequentiallycascades
- propagate — to spread or move outward from a source
- operando — measuring a device while it is operating
- laminography — X-ray technique to image three-dimensional structures
- electrode — a conductor where electrical reactions occur
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could manufacturers change electrode design to reduce strain and extend battery life? Give one or two possible ideas.
- What might be the advantages and disadvantages of applying controlled pressure to battery cells?
- How could real-time imaging techniques like operando TXM influence future battery research or product testing?
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