Researchers find manganese can cause battery flaw that may shorten EV lifespans

While cobalt-free, high-nickel cathode batteries such as manganese-coated nickel core batteries have emerged as a potential method to increase EV driving range while reducing dependence on expensive critical minerals, research suggests that exposing precursor material to air can cause subtle chemical changes that later accelerate battery degradation.

A study at Hanyang University in South Korea found that exposing battery precursor materials to air alters manganese chemistry, creating reactive surface defects that accelerate electrolyte breakdown and could significantly reduce the lifespan of these next-generation batteries.

An adjustment in lithium content during synthesis can suppress these defects and restore stability, helping manufacturers develop longer-lasting, high-energy batteries for future electric vehicles, according to the research team led by Professor Jin Ho Bang along with PhD Scholar JinHa Shim.

The findings of the study were published in Volume 19, Issue 12 of the journal Energy and Environmental Science.

The team observed that manganese 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. This hidden defect can nearly double the rate of capacity fading in nickel-rich battery systems 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,” explained Professor Bang. “Even small variations in precursor storage history can substantially affect battery stability.”

To overcome this problem, the researchers suggest that increasing the amount of excess lithium during synthesis 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, improving long-term durability.

“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,” Professor Bang added. Rather than 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 lifespans and also support the durability of large-scale energy storage systems that would require stable, high-energy batteries for renewable energy applications in future, the research found.

Source: Hanyang University ERICA