WMG research provides new insights into how battery cathodes store energy

The Battery Cells and Materials Group at Warwick Manufacturing Group (WMG) has published a new paper in Nature Nanotechnology that provides fresh insights into one of the fundamental questions in battery science: where does the charge come from?

The study, led by Associate Professor Galo Paez Fajardo and Professor Louis Piper, examined how lithium-ion battery cathodes store and release energy during operation. While conventional understanding suggests that electrons are primarily removed from metal ions such as nickel, cobalt and iron during charging, the researchers found evidence that oxygen ions can also play a significant role in the energy storage process.

Using advanced X-ray techniques to study batteries during charging, the team compared two widely used cathode materials: lithium iron phosphate (LFP) and nickel manganese cobalt oxide (NMC). While LFP showed little oxygen participation, the layered oxide material demonstrated significant electron extraction from oxygen ions, in some cases greater than from the metal sites themselves.

Dr Galo Paez Fajardo said:

These fundamental studies of real electrodes and cells are important because they put constraints on the models used for battery material searches. Showing how and why oxygen ions participate is important for determining how to improve our current batteries.”

The findings provide new insights into how battery materials operate and could help guide the development of higher-energy cathodes for future electric vehicles and aircraft.

Professor Louis Piper added:

This work provides new design rules for engineering the next-generation high-energy cathodes. 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 cathodes.”

Funded through the Faraday Institution’s LEAP project, the research involved scientists from WMG, Diamond Light Source and partner institutions in Ireland and Germany.

Explore the paper and its insights in full: Direct evidence of metal–ligand redox processes in positive electrodes during lithium-based battery operation