New POSTECH study reveals the atomic-level flaw behind capacity fade and shows how a simple aluminum substitution can make high-nickel EV batteries last longer and run safer.
Study: Origin of Double Ligand Holes and Abnormal Inductive Effect of np6 Elements in Ni-rich Cathodes. Image Credit: VADZIM SHUBICH/Shutterstock.com
The research team, led by Professor Kyu-Young Park, has identified internal structural distortion, leading to "oxygen holes," as the primary cause of rapid performance degradation in high-nickel electric vehicle (EV) batteries.
Their findings, published in Advanced Functional Materials, also show that adding a small amount of aluminum (Al) to the cathode can significantly extend battery lifespan by preventing these defects.
According to the team, this approach offers a practical way to enhance both energy density and long-term stability in EV batteries.
High-nickel cathodes are used in electric vehicle (EV) batteries to increase driving range. However, this high nickel content causes rapid degradation of battery performance during charging and discharging.
The core issue is this internal structural distortion, which the researchers liken to a warped pillar cracking a building's wall.
As manufacturers push to store more energy in each cell, nickel levels continue to climb. But while this trend improves energy density, it also accelerates capacity fade across repeated cycles.
The POSTECH team sought to identify the atomic-level mechanism driving this decline.
Their analysis revealed that capacity fading originates from lattice distortion occurring naturally during the charge-discharge process. This distortion creates significant oxygen holes around oxygen atoms, destabilizing the lattice and shortening battery lifespan.
The team successfully prevented the formation of these oxygen holes by substituting a small amount of nickel with aluminum. The aluminum stabilizes the structure by improving the electronic environment around the oxygen atoms.
Testing confirmed that this adjustment delivers a substantial improvement in lifespan.
This work is notable not only for identifying the atomic-scale cause of degradation in high-nickel cathodes, but also for presenting a strategy to enhance energy density and lifespan at the same time.
This study, which identifies the capacity degradation caused by structural distortion in high-nickel cathodes for EVs, will help expand the design possibilities for next-generation, high-performance batteries. This achievement provides a key strategy that not only improves lifespan but can also mitigate thermal runaway, a critical issue in high-nickel cathodes. We expect it to have a significant impact on the entire rechargeable battery industry.
Kyu-Young Park, Study Lead and Professor, POSTECH
Journal Reference:
Choi, E. et al. (2025) Origin of Double Ligand Holes and Abnormal Inductive Effect of np6 Elements in Ni-rich Cathodes. Advanced Functional Materials. DOI:10.1002/adfm.202512501.