Even when the laptop or mobile phone is turned off, lithium-ion batteries discharge on their own, albeit slowly. This phenomenon is so common that most people don’t usually wonder why it happens. And now Professor Michael Metzger from the Department of Physics and Atmospheric Sciences at Dalehousie University in Canada: published a study with the discovery of why batteries discharge themselves.

Professor Metzger studies batteries because, he says, although they are extremely advanced, they can still be perfect. During the study, the scientist opened several batteries and exposed them to different temperatures. In a battery exposed to 25°C, the electrolyte solution did not change, but a battery exposed to 55°C changed color and turned brown. Finally, a battery exposed to 70°C turned “blood red”.

The color change was a sign that the temperature difference was causing a chemical reaction in the battery. When conducting a chemical analysis of the compound, the scientist made a discovery that for many years remained unnoticed by people. The color change was caused by the presence of plastic in the batteries, since each battery has a tape that holds the electrodes together. It is the decomposition of this plastic that leads to the natural discharge of batteries: “Commercial batteries have a PET tape, similar to adhesive tape, that holds the electrodes together, and this tape chemically decomposes, resulting in a molecule that leads to discharge automatically,” explained Metzger.

Decomposition of the tape causes a chemical reaction

Over time and exposure to different temperatures PET tape degrades and forms a molecule that causes the battery to drain even when not in use.. “In our lab, we do a lot of very complex experiments to improve batteries, but this time we found a very simple thing. exposure to lithium ions degrade cells.”

The discovery may seem simple, but it should prompt companies around the world to look for a more stable solution for bonding ion battery electrodes. With new material in the future, we may be able to have more durable batteries that don’t drain when not in use. With so many technological advances, it’s interesting to see how science can be improved even in the smallest detail.

The Galaxy S23 line was designed with sustainability in mind
The Galaxy S23 Ultra smartphone contains a large amount of recycled materials

Source: CBC Canada, Dalhousie.

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