In a recent study published in the Journal of The Electrochemical Society, Tim Kipfer, Rafael B. Berk, Felix Riewald, Michele Piana, and Hubert A. Gasteiger (TUM Chair of Technical Electrochemistry) investigate how the composition of cobalt-free, lithium-rich layered oxides (LR-NMs) relates to open-circuit-voltage (OCV) hysteresis. This link is crucial because OCV hysteresis markedly reduces the energy efficiency of this promising class of cathode materials for lithium-ion batteries.
🔗 Open-access article: https://iopscience.iop.org/article/10.1149/1945-7111/ae0526
Highlights:
- Systematic materials study: A series of cobalt-free LR-NM cathodes with deliberately varied lithium and manganese contents was synthesized and examined.
- Correlation: The study demonstrates a direct, linear correlation between the extent of reversible anionic redox and the magnitude of OCV hysteresis.
- Composition effect: Higher lithium and/or manganese content leads to stronger hysteresis and, consequently, lower energy efficiency.
- Design guidance: Ni-rich LR-NMs or those with a Ni/Mn ratio near 1:1 offer the best compromise to improve energy efficiency without significantly compromising energy density.