The battery life of lithium batteries will be significantly lower after long-term use. This is largely due to impurities that form during battery cycling, and now a team led by the Nobel laureate and inventor of the rechargeable lithium battery may have found a solution to this problem – a new type of coating.
During lithium battery cycling, these impurities accumulate in the battery’s nickel-rich cathode. In lithium batteries, although nickel is the key to energy density, it is also unstable.
This resulted in the formation of impurities on the cathode surface during the first charge and discharge cycle, which in turn immediately reduced the battery’s storage capacity by 10 to 18 percent.
In addition, nickel creates instability beneath the surface of the cathode structure, which also begins to reduce the battery’s storage capacity over time.
In 2019, Stanley Whittingham and two other scientists were awarded the Nobel Prize in Chemistry for developing lithium-ion batteries in the 1970s.
The technology has come a long way since then, but researchers, including Whittingham, are still working to improve them by experimenting with different materials, and one promising material for a cathode is a nickel called NMC 811. Manganese cobalt material.
Led by Whittingham, a team of researchers from SUNY Binghamton, the Department of Energy, and Oak Ridge National Laboratory conducted multiple chemical studies of NMC 811.
Hopefully this will prevent instability in the cathode, which the researchers investigated through X-ray and neutron diffraction studies.
“Neutrons can easily penetrate the cathode material, revealing the positions of niobium and lithium atoms, which provides a better understanding of how the niobium modification process works,” said researcher Hui Zhou. Neutron scattering data suggest that niobium atoms are stable At higher temperatures, niobium atoms replace some of the manganese atoms deeper inside the cathode material to improve long-term capacity retention.”
Talking about this nickel-manganese-cobalt material reduces capacity loss during the first charge cycle. Later, it also provided better long-term performance, resulting in a capacity retention rate of 93.2% over 250 charge cycles.
Scientists see great potential in new battery designs, especially where high-density storage is a priority, such as in electric transport.
“Electrochemical performance and structural stability make NMC 811 a candidate cathode material for higher energy density applications such as electric vehicles,” Whittingham said. Combining niobium coatings with replacing manganese atoms with niobium atoms , may be a better way to improve initial capacity and long-term capacity retention. These modifications can be easily scaled up using the current multi-step fabrication process for NMC materials.”