An Atomic Look at Next Generation Batteries
Venkat Viswanathan and his colleagues recently published a paper in Nature describing their research in the anionic reduction-oxidation mechanism of lithium-rich cathodes. Normal Li-ion batteries work because of cationic redox, where a metal ion changes its oxidation state as lithium is added or removed. However, only one lithium ion can be stored per metal ion. Lithium-rich cathodes on the other hand can store more, and researchers attribute this to the anionic redox mechanism.
The team set out to find conclusive evidence of this by using Compton scattering, a phenomenon where a photon deviates from a trajectory after interacting with a particle such as an electron. They observed how electron beams’ orbits in the anionic redox activity can be imaged and visualized and its character and symmetry determined.
Previous research has not been able to provide a clear image of the quantum mechanical electronic orbitals related to redox reactions because standard experiments could not measure it. However, when the team saw the agreement in redox character between theory and experimental results, they realized that they could image the oxygen states that are responsible for the redox mechanism.
The gathered evidence supports the anionic redox mechanism in a lithium-rich battery material. Furthermore, the study provides a clear image of a lithium-rich battery at the atomic level and suggests pathways for improving and designing next generation cathodes for electric aviation.