Breakthrough in Battery Degradation Mechanism Promises Longer-Lasting Energy Storage

New research has revealed why lithium-ion batteries lose capacity over time, offering hope for longer-lasting batteries in portable electronic devices and renewable energy storage systems.

An international team, led by engineers from the University of Colorado Boulder, has uncovered the molecular processes responsible for battery degradation. Their findings, published on 12th September in Science, could pave the way for better battery designs.

“We are advancing lithium-ion batteries by identifying the molecular mechanisms involved in their degradation,” said Michael Toney, the paper’s corresponding author and professor of Chemical and Biological Engineering. “Better batteries are essential for shifting from fossil fuels to renewable energy sources.”

Cobalt-Free Batteries: A Persistent Challenge

Scientists have long worked to develop cobalt-free lithium-ion batteries due to the high cost of the mineral and its associated human rights concerns. Most of the world’s cobalt is mined in the Democratic Republic of Congo, where mining practices often involve child labour. However, alternative materials like nickel and magnesium have not fared well, exhibiting even higher rates of self-discharge—an issue that shortens battery lifespan.

Self-discharge occurs when internal chemical reactions reduce the energy stored in the battery, limiting its capacity over time. In portable devices like smartphones and laptops, this leads to a gradual reduction in battery life, requiring more frequent charging cycles.

Hydrogen’s Role in Battery Degradation

Using the Advanced Photon Source at Argonne National Laboratory, Toney’s team discovered that hydrogen molecules from the electrolyte move to the cathode and displace lithium ions. These lithium ions typically bind to the cathode to help power electronic devices. As hydrogen takes their place, fewer lithium ions are available, reducing battery capacity and leading to quicker degradation.

Understanding this process opens up new possibilities for improving battery life. Engineers can now explore strategies like coating the cathode to block hydrogen molecules or using a different electrolyte to slow down degradation.

Implications for Portable Devices and Energy Storage

The rise of portable devices, such as smartphones, tablets, and laptops, has made battery life a critical concern for consumers. As batteries degrade, these devices require more frequent charging, reducing their usability and convenience.

The findings offer a path to longer-lasting batteries that could significantly extend the time between charges for portable electronics. This would not only enhance user experience but also reduce electronic waste, as devices would last longer before needing battery replacements.

By addressing the issue of self-discharge, this research could also improve energy storage systems for renewable power, advancing the transition to sustainable energy.

The full paper “Solvent-mediated oxide hydrogenation in layered cathodes” is available to read in Science.