Manganese Oxidation Defects Identified as Key Cause of High-Nickel Battery Degradation
A research team at Hanyang University in South Korea has recently published findings revealing that when precursor materials for high-nickel batteries are exposed to air during manufacturing, manganese surface oxidation generates highly reactive defects. These defects accelerate battery capacity fading by nearly doubling the degradation rate in nickel-rich battery systems during extended charge-discharge cycling tests. The study highlights that these defective regions trigger electrolyte breakdown, transition-metal dissolution, and damaging reactions with the graphite anode.
The research, led by Professor Jin Ho Bang and PhD scholar JinHa Shim at Hanyang University, was published in the journal *Energy and Environmental Science*. The team found that manganese-rich shells, originally designed to protect high-nickel cathodes, can instead become catalysts for battery degradation if precursor materials are improperly stored. Oxidation of manganese under such conditions produces 'Jahn-Teller distorted' defects, which undermine battery stability. Professor Jin Ho Bang emphasized that even minor variations in the storage history of precursor materials can significantly affect battery stability, stressing that this issue cannot be overlooked in large-scale battery manufacturing.
Adjusting Lithium Content Effectively Suppresses Defect Formation
The research team further explored potential solutions and discovered that increasing lithium content during synthesis effectively suppresses the formation of defective surface phases while restoring the stability of manganese-oxygen bonds. Experimental results demonstrated that modified cathode materials retained over 90% of their initial capacity after prolonged use, markedly improving battery durability. Professor Jin Ho Bang noted that compared to costly coating technologies or production line overhauls, precise control of precursor material handling and lithium stoichiometry offers a more economical and feasible approach to improvement.
The research team suggested that these findings could not only extend the lifespan of electric vehicle batteries but also enhance the stability of batteries in large-scale energy storage systems, thereby supporting renewable energy applications. However, the study has so far only been validated under laboratory conditions and has not yet been tested on actual electric vehicle battery packs. Additionally, the specific conditions of air exposure—such as humidity, temperature, and duration—that influence manganese oxidation require further clarification. Industry adoption of these recommendations will also determine the practical effectiveness of the proposed solutions.
Despite these uncertainties, the study underscores the critical role of precursor material management in battery manufacturing. Professor Jin Ho Bang stated that the handling of precursor materials could become a hidden variable determining battery lifespan, and manufacturers should treat it as a vital step in the production process. While this research offers new insights for the commercialization of high-nickel batteries, implementing precise control in mass production remains a challenge the industry must address.
