Your Phone Battery Is Constantly ‘Breathing’ and That Motion May Be What Eventually Kills It

All batteries of all types degrade over time with use. Researchers now better understand why that happens.

Lithium-ion batteries don’t just sit there storing energy. They breathe. Well, sort of.

Every time you charge your phone or unplug an electric car, the battery’s internal parts subtly expand and contract. Over thousands of cycles, that motion adds up. According to new research, this mechanical breathing subtly deforms batteries from the inside out, weakening them until they fail.

The discovery helps explain a long-standing mystery in energy science: why even well-designed batteries inevitably lose capacity steadily, no matter how carefully they’re used.

The work comes from a collaboration between researchers at the University of Texas at Austin, Northeastern University, Stanford University, and Argonne National Laboratory. Their findings were published last week in Science.

Batteries That Expand and Contract — Until They’re Destroyed

All batteries of all types degrade over time with use. What engineers haven’t fully understood is how microscopic changes turn into macroscopic failure.

The new research points to a process called chemomechanical degradation. Each charging cycle pushes lithium ions into battery electrodes. Discharging pulls them back out. That chemical movement causes physical stress.

“With every ‘breath’ of the battery, there’s some degree of irreversibility,” says Yijin Liu, an associate professor at the University of Texas at Austin and leader of the study. “This effect accumulates over time, eventually causing failure of the cell.”

Think of it like bending a paper clip. One bend does nothing. A thousand bends snap it in half.

What makes batteries especially vulnerable is the fact that each electrode contains hundreds of thousands of microscopic particles packed together, all responding differently to stress.

A Chain Reaction Inside Electrodes

The researchers uncovered something new inside this crowded microscopic world: strain cascades.

These cascades occur when stress builds up in one region of an electrode and spreads outward, triggering damage elsewhere. It’s less like a uniform stretch and more like a crack rippling through ice.

“We were able to see that every particle behaves differently under electrochemical stress,” says Juner Zhu, an assistant professor at Northeastern University and coauthor of the study, according to a press release. “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.”

That uneven motion matters. When one particle shifts quickly and its neighbors don’t, mechanical tension builds. Over time, those stressed zones fracture. Cracks form and electrical pathways naturally break down.

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Once that starts, degradation accelerates.

Watching Batteries Fail in Real Time

Using advanced imaging tools such as operando transmission X-ray microscopy and 3D X-ray laminography, the researchers captured real-time images of electrodes during charging and discharging. These techniques let scientists peer inside intact batteries without cutting them in half or physically altering them in any way.

This approach reflects a broader trend in materials science. Over the past decade, researchers have increasingly relied on “operando” methods — studying materials as they function, rather than after failure. That shift has already transformed fields like catalysis and semiconductor research.

In batteries, it’s proving just as powerful.

The first hints of this breathing behavior appeared unexpectedly, while the team was studying a different device altogether: commercial wireless earbuds. The tiny batteries inside them revealed the same mechanical stresses seen in larger cells.

Why This Matters Beyond Gadgets

Battery degradation isn’t just an inconvenience. It’s a bottleneck for climate technology.

Electric vehicles rely on batteries that must survive years of daily charging. Renewable energy grids depend on storage systems that cycle constantly. Short battery lifespans raise costs, increase waste, and slow the adoption of clean technology the world so desperately needs.

By pinpointing how and where mechanical strain builds up, the new research offers some practical guidance for battery designers.

For example, the team suggests that applying carefully controlled pressure to battery cells could help limit damaging deformation. Engineers might also redesign electrodes so particles move more uniformly, reducing strain cascades before they start.

“Our ultimate goal is the creation of advanced technologies that can substantially increase the utility and durability of batteries,” says Jason Croy, a group leader at Argonne National Laboratory and coauthor of the study. “Understanding how the design of electrodes influences their response to stress is a critical step in pushing the boundaries of what batteries can do.”

From ‘Breathing’ Cells to Better Energy Futures

The new findings don’t replace earlier explanations for battery degradation. Temperature still accelerates chemical breakdown. Charging too fast still promotes lithium plating. High voltages still push electrolytes beyond their limits. But mechanical strain can amplify all of these effects by creating fractures, isolating particles, and disrupting electrical pathways.

Battery research often focuses on novel materials, electrolytes, and chemical reactions. This study reminds us that physics matters just as much.

A battery is not a static box. It’s a dynamic system, constantly moving at scales too small to see with the naked eye.

By treating batteries as mechanical organisms that age with every breath, scientists are reframing a familiar problem. The next step, the researchers say, is to develop theoretical models that link chemical reactions and mechanical stress more tightly.

If they succeed, future batteries may still buckle but they’ll do it without slowly tearing themselves apart. Or maybe if this goal is too lofty, the batteries might at least last longer. Every bit longer counts.

In some cases, that could make the difference between energy systems that merely work and ones that truly last.