Electric vehicles continue to gain popularity each year, with improved batteries playing a crucial role in making them more affordable and practical. One of the most promising advancements involves high-nickel batteries that avoid using cobalt, a costly and hard-to-source mineral. These next-generation batteries can hold more energy, extending the driving range of electric cars at a lower cost.
However, new research from Hanyang University in South Korea has uncovered a surprising issue that could reduce the lifespan of these advanced batteries even before they hit the road. Published in Energy and Environmental Science, the study reveals that exposing battery materials to air during manufacturing can cause hidden damage that accelerates battery degradation over time.
The researchers focused on materials used to create high-nickel cathodes, which are key components in lithium-ion batteries. These cathodes often contain manganese, added to enhance stability and protect the battery during operation. They discovered that when the precursor materials used in making these cathodes are stored in areas exposed to air, the surface manganese begins to react with oxygen. Although this reaction is tiny and difficult to observe, it creates microscopic imperfections in the material.
These hidden defects make the battery’s chemistry more reactive once in use. During charging and discharging cycles, the damaged surfaces can cause the liquid electrolyte inside the battery to break down. Additionally, metal particles can dissolve, leading to harmful reactions with the graphite anode. Collectively, these issues cause the battery to lose its storage capacity much more quickly than expected.
The study showed that batteries made from air-exposed materials experienced nearly twice the capacity loss over time compared to those manufactured under more controlled conditions. On a positive note, the team discovered a straightforward solution: by adding a small amount of extra lithium during the manufacturing process, they could prevent the surface defects from forming. This simple adjustment helped restore stable chemical bonds between manganese and oxygen, significantly improving the cathode’s durability.
Laboratory testing of these improved batteries demonstrated that they could retain over 90% of their original capacity even after extended use, marking a substantial leap in long-term performance. The findings suggest that manufacturers might not need costly new coatings or major factory overhauls to produce longer-lasting batteries. Instead, paying close attention to how raw materials are stored before production and fine-tuning the amount of lithium added during manufacturing could make a big difference in battery lifespan.
This research underscores an important point for the battery industry: while moving away from cobalt is a vital goal, understanding how other materials like manganese behave during manufacturing is equally essential. Better control of these hidden chemical changes could help future electric vehicles travel farther, last longer, and offer more reliable energy storage for renewable power systems.
The study was conducted by researchers at Hanyang University and published in Energy and Environmental Science.