Hanyang University ERICA Researchers Uncover a Hidden Battery Flaw That May Shorten EV Lifespans

Researchers reveal how air exposure alters manganese-coated battery materials and how the damage can be prevented

GYUNGGI-DO, South Korea, July 28, 2026 /PRNewswire/ -- As the need for sustainable electric vehicles increases, cobalt-free high-nickel cathode batteries (such as manganese-coated nickel core batteries) have emerged as one of the most promising technologies. These batteries increase the driving range while reducing dependence on expensive critical minerals. However, a new study suggests that a hidden weakness in the battery material could significantly reduce the lifespan of these next-generation batteries.

A research team led by Professor Jin Ho Bang along with PhD Scholar JinHa Shim from Hanyang University, South Korea has discovered that simply exposing precursor materials used to manufacture these cathodes to air can trigger subtle chemical changes that later accelerate battery degradation. The study reveals an overlooked challenge in battery production and provides a practical strategy to improve long-term performance. The findings of the study were made available online on May 13, 2026 and were published in Volume 19, Issue 12 of the journal Energy and Environmental Science on June 23, 2026.

The team observed that manganese, an element which is commonly used to stabilize high-nickel cathodes, can unexpectedly become a source of instability under certain manufacturing conditions. The storage of precursor materials in air exposed areas leads to the oxidation of manganese on the particle surface which then results in the formation of defective regions enriched with "Jahn-Teller distorted" manganese species. These distorted surfaces become highly reactive, leading to electrolyte decomposition, transition-metal dissolution and damaging reactions with the graphite anode. In nickel-rich battery systems, this hidden defect can nearly double the rate of capacity fading during extended battery cycling tests.

"We found that a manganese-rich shell, which is normally introduced to protect high-nickel cathodes, can instead become a catalyst for degradation if the precursor chemistry is not carefully controlled," explains Prof. Bang, "Even small variations in precursor storage history can substantially affect battery stability."

To overcome this problem, the researchers suggest a simple solution. By increasing the amount of excess lithium during synthesis, they could suppress the formation of defective surface phase and restore stable manganese-oxygen bonding. These modified cathodes could retain more than 90% of their capacity, demonstrating a significant improvement in long-term durability.

While global efforts to lower battery costs and reduce reliance on cobalt have been rapidly driving the development of ultra-high-nickel and manganese-rich cathodes for electric vehicles, this study offers critical guidance to the industry. Moreover, the study highlights that eliminating cobalt alone is insufficient; understanding how manganese chemistry evolves during manufacturing is equally important.

"Our results show that even minor variations in precursor history can have major consequences for battery performance, making precursor management an important consideration for large-scale manufacturing," adds Prof. Bang. Instead of requiring expensive coatings or major redesigns of production lines, careful control of precursor handling and lithium stoichiometry could provide a comparatively upfront route towards more durable batteries. These improvements could eventually translate into electric vehicles with longer battery lifetimes and also benefit large-scale energy storage systems that would require stable, high-energy batteries for renewable energy applications in future.

Reference
Title of original paper: Precursor-driven Jahn–Teller distortion as a hidden origin of surface instability in Mn-stabilized Ni-rich cathodes
Journal: Energy and Environmental Science
DOI: 10.1039/d6ee00713a 

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