Rational design of Li off-stoichiometric Ni-rich layered cathode materials for Li-ion batteries

The electrification trend in the automotive industry is fueling research on Ni-rich layered NCM cathode materials with high specific capacities. The simplest way to maximize the electrochemical performance of Ni-rich NCM is to tune the crystal structure by controlling the Li content and synthesis temperature. Herein, we demonstrate the critical roles of the Li content and synthesis temperature in determining the crystal structure of Li-excess Ni-rich NCM with enhanced electrochemical performance. The crystal structure of Li-excess Ni-rich NCM was systemically investigated using X-ray diffraction, neutron diffraction, and X-ray absorption spectroscopy, revealing that excess Li can be accommodated in Ni-rich NCM as the synthesis temperature decreases, resulting in stable cycle performance at high working voltage. We believe that our findings provide a rational reason for the excess amount Li required for optimization of the synthesis of Ni-rich NCM and offer insight for the simplest design of Ni-rich cathode materials that are stable under high-voltage operation. © 2022 Elsevier B.V.

Description

This work was supported by the National Research Foundation of Korea (NRF) funded by the Korea government (MSIT) (Grant No. NRF-2017M2A2A6A05017652 and 1711139323). This work was also supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government (MOTIE) (20221B1010003B, Integrated High-Quality Technology Development of Remanufacturing Spent Cathode for Low Carbon Resource Recirculation) and RIST-POSCO R&D program funded by POSCO (2020A023). Neutron total scattering measurement was approved by the Neutron Science Proposal Review Committee of J-PARC MLF (Proposal No. 2020A0017).

Keywords

Lithium, Lithium ion batteries, Stoichiometry, Cathodes, Nickel, Electrochemistry, Crystal structure, Synthesis, Neutron diffraction, Spectroscopy

Citation

Song, S. H., Hong, S., Cho, M., Yoo, J.-G., Min Jin, H., Lee, S.-H., Avdeev, M., Ikeda, K., Kim, J., Nam, S. C., Yu, S.-H., Park, I., & Kim, H. (2022). Rational design of Li off-stoichiometric Ni-rich layered cathode materials for Li-ion batteries. Chemical Engineering Journal, 448, 137685. doi:10.1016/j.cej.2022.137685