A new paper published today in Nature Energy reveals how a collaborative team of researchers have been able to fully identify the nature of oxidised oxygen in the important battery material – Li-rich NMC – using RIXS (Resonant Inelastic X-ray Scattering) at Diamond. This compound is being closely considered for implementation in next generation Li-ion batteries because it can deliver a higher energy density than the current state-of-the-art materials, which could translate to longer driving ranges for electric vehicles. They expect that their work will enable scientists to tackle issues like battery longevity and voltage fade with Li-rich materials.
The paper, ‘First cycle voltage hysteresis in Li-rich 3d cathodes associated with molecular O2 trapped in the bulk’ by a joint team from the University of Oxford, the Henry Royce and Faraday Institutions and Diamond, examines the results of their investigations to better understand the important compound known in the battery industry as Li-rich NMC (or Li1.2Ni0.13Co0.13Mn0.54O2).
Principal Beamline Scientist on I21 RIXS at Diamond, Kejin Zhou,said:
Our work is much about understanding the mysterious first cycle voltage hysteresis in which the O-redox process cannot be fully recovered resulting in the loss of the voltage hence the energy density.
Read more on the Diamond website
Image: A previous study (Nature 577, 502–508 (2020)) into this process made by the same research team, at the I21 beamline at Diamond, reported that, in Na-ion battery cathodes, the voltage hysteresis is related to the formation of molecular O2 trapped inside of the particles due to the migration of transition metal ions during the charging process.