South Korean scientists suggest how to extend the lifespan of lithium-ion batteries.

A team of researchers from Pohang University of Science and Technology (POSTECH), in collaboration with Sungkyunkwan University, has announced a discovery that could change the way we use lithium-ion batteries. It turns out that a seemingly simple rule—avoiding complete battery discharge—can significantly extend their lifespan.

Don’t fully discharge the battery
It was previously commonly believed that overcharging batteries led to their degradation. However, recent studies show that the problem may lie elsewhere. As Professor Jihyun Hong emphasizes, the actual discharge process—especially at stable voltage levels with low energy—can lead to irreversible damage to the cathode.

The cathode, one of the two electrodes in a cell, plays a key role in degradation. During discharge, when the voltage approaches 3V, oxygen starts to “escape” from the cathode’s surface, reacting with lithium to form lithium oxide. This compound interacts with the electrolyte, producing gas that leads to swelling and damage to the cell.

More nickel = less durability?
The problem is particularly pronounced in batteries with a high nickel content, which are often chosen as a cheaper alternative to cobalt-based batteries. Despite their lower cost, these cells are more prone to gas degradation. Experiments have shown that batteries subjected to regular, deep discharge exhibited only 3.8% capacity retention after 250 cycles. In contrast, the same batteries used with higher voltages maintained over 73% capacity after 300 cycles.

Why does this matter?
A better understanding of degradation processes in batteries is crucial for the development of electric vehicles and energy storage technologies. Improved batteries will not only enhance the reliability and range of electric cars but also help more effectively integrate renewable energy sources, supporting the energy transition.

Moreover, even small changes in usage habits—such as avoiding complete discharge—can help extend the lifespan of batteries in everyday devices like smartphones, laptops, or headphones.

Implications for users and manufacturers
The discovery by South Korean scientists is not just a technical curiosity; it’s a practical tip that could be implemented on a wide scale. Designers of battery management systems (BMS) in electric vehicles and consumer electronics may consider this new data to better protect batteries from premature degradation.