Researchers uncover how oxygen plays a much larger role in storing energy, potentially reshaping the design of future lithium ion batteries.
Researchers at the Battery Cells and Materials Group at WMG, University of Warwick, have uncovered new evidence that challenges a long accepted understanding of how lithium ion batteries store and release energy. Published in Nature Nanotechnology, the study shows that oxygen ions play a much larger role in battery charging than previously believed, offering fresh insights for designing higher capacity batteries.
For decades, scientists believed that the electrical charge in lithium ion battery cathodes came mainly from metal ions such as nickel, cobalt and iron as lithium ions moved during charging. Oxygen ions were largely considered inactive participants. This understanding has shaped battery modelling and material development for years.
Using advanced X-ray techniques to observe batteries during operation, the researchers found that layered oxide cathodes, commonly used in electric vehicles, extract a significant number of electrons from oxygen ions, in some cases more than from the metal ions themselves. In contrast, lithium iron phosphate cathodes showed very little oxygen participation, revealing that different battery chemistries store energy in fundamentally different ways.
The findings could help researchers improve the energy density of next generation batteries without relying solely on conventional material optimisation. Understanding how oxygen and metal ions work together may enable the development of cathodes that store more energy while maintaining stability and performance, making them attractive for electric vehicles, aircraft and other high demand applications.
The study also provides new design principles for future battery materials by explaining why oxygen participation varies across different cathode chemistries. According to the researchers, these insights will help refine battery models and guide the search for higher capacity materials.
“Instead of treating metal and oxygen redox as separate, this work helps explain how they cooperate and identifies new ways to think about higher capacity cathode,” says Professor Louis Piper, Professor of Battery Innovation at WMG, University of Warwick.
